Multicast Control Extensions for the Access Node Control Protocol (ANCP)
RFC 7256
| Document | Type |
RFC - Proposed Standard
(July 2014; No errata)
Updates RFC 6320
|
|
|---|---|---|---|
| Authors | François Le Faucheur , Roberta Maglione , Tom Taylor | ||
| Last updated | 2018-12-20 | ||
| Stream | Internet Engineering Task Force (IETF) | ||
| Formats | plain text html pdf htmlized bibtex | ||
| Reviews | |||
| Stream | WG state | Submitted to IESG for Publication | |
| Document shepherd | Matthew Bocci | ||
| Shepherd write-up | Show (last changed 2013-11-19) | ||
| IESG | IESG state | RFC 7256 (Proposed Standard) | |
| Action Holders |
(None)
|
||
| Consensus Boilerplate | Unknown | ||
| Telechat date | |||
| Responsible AD | Ted Lemon | ||
| Send notices to | (None) | ||
| IANA | IANA review state | IANA OK - Actions Needed | |
| IANA action state | RFC-Ed-Ack | ||
Internet Engineering Task Force (IETF) F. Le Faucheur
Request for Comments: 7256 R. Maglione
Updates: 6320 Cisco
Category: Standards Track T. Taylor
ISSN: 2070-1721 Huawei
July 2014
Multicast Control Extensions for the Access Node Control Protocol (ANCP)
Abstract
This document specifies the extensions to the Access Node Control
Protocol (ANCP) (RFC 6320) required for support of the multicast use
cases defined in the Access Node Control Protocol framework document
(RFC 5851) and one additional use case described in this document.
These use cases are organized into the following ANCP capabilities:
o multicast replication initiated by the Network Access Server
(NAS);
o conditional access and admission control with white and black
lists;
o conditional access and admission control with grey lists;
o bandwidth delegation; and
o committed bandwidth reporting.
These capabilities may be combined according to the rules given in
this specification.
This document updates RFC 6320 by assigning capability type 3 to a
capability specified in this document and by changing the starting
point for IANA allocation of result codes determined by IETF
Consensus from 0x100 to 0x64.
Le Faucheur, et al. Standards Track [Page 1]
RFC 7256 ANCP Multicast Extensions July 2014
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7256.
Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction ....................................................5
1.1. A Note on Scope ............................................7
2. Terminology .....................................................7
3. Multicast Use Cases .............................................7
3.1. NAS-Initiated Multicast Replication Control Use Case .......8
3.1.1. Goals ...............................................8
3.1.2. Message Flow ........................................9
3.2. Conditional Access and Admission Control Use Case ..........9
3.2.1. Goals ...............................................9
3.2.2. Message Flow .......................................10
3.3. Multicast Flow Reporting Use Case .........................11
3.3.1. Goals ..............................................11
3.3.2. Message Flow .......................................11
3.4. Committed Bandwidth Reporting Use Case ....................11
3.4.1. Goals ..............................................11
3.4.2. Message Flow .......................................12
4. ANCP Messages ..................................................13
4.1. Provisioning Message ......................................13
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4.1.1. Sender Behavior ....................................14
4.1.2. Receiver Behavior ..................................14
4.2. Port Management Message ...................................15
4.2.1. Sender Behavior ....................................16
4.2.2. Receiver Behavior ..................................16
4.3. Multicast Replication Control Message .....................17
4.3.1. Sender Behavior ....................................21
4.3.2. Receiver Behavior ..................................21
4.4. Multicast Admission Control Message .......................24
4.4.1. Sender Behavior ....................................25
4.4.2. Receiver Behavior ..................................26
4.5. Bandwidth Reallocation Request Message ....................27
4.5.1. Sender Behavior ....................................28
4.5.2. Receiver Behavior ..................................28
4.6. Bandwidth Transfer Message ................................31
4.6.1. Sender Behavior ....................................32
4.6.2. Receiver Behavior ..................................32
4.7. Delegated Bandwidth Query Request Message .................34
4.7.1. Sender Behavior ....................................34
4.7.2. Receiver Behavior ..................................34
4.8. Delegated Bandwidth Query Response Message ................34
4.8.1. Sender Behavior ....................................35
4.8.2. Receiver Behavior ..................................35
4.9. Multicast Flow Query Request and Response Messages ........36
4.9.1. Sender Behavior ....................................36
4.9.2. Receiver Behavior ..................................37
4.10. Committed Bandwidth Report Message .......................38
4.10.1. Sender Behavior ...................................38
4.10.2. Receiver Behavior .................................39
5. ANCP TLVs For Multicast ........................................39
5.1. Multicast-Service-Profile TLV .............................39
5.2. Multicast-Service-Profile-Name TLV ........................41
5.3. List-Action TLV ...........................................41
5.4. Sequence-Number TLV .......................................44
5.5. Bandwidth-Allocation TLV ..................................45
5.6. White-List-CAC TLV ........................................45
5.7. MRepCtl-CAC TLV ...........................................46
5.8. Bandwidth-Request TLV .....................................46
5.9. Request-Source-IP TLV .....................................47
5.10. Request-Source-MAC TLV ...................................48
5.11. Request-Source-Device-Id TLV .............................48
5.12. Multicast-Flow TLV .......................................49
5.13. Report-Buffering-Time TLV ................................50
5.14. Committed-Bandwidth TLV ..................................51
6. Multicast Capabilities .........................................51
6.1. Required Protocol Support .................................52
6.1.1. Protocol Requirements for NAS-Initiated
Multicast Replication ..............................52
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6.1.2. Protocol Requirements for Committed
Multicast Bandwidth Reporting ......................54
6.1.3. Protocol Requirements for Conditional
Access and Admission Control with White
and Black Lists ....................................55
6.1.4. Protocol Requirements for Conditional
Access and Admission Control with Grey Lists .......56
6.1.5. Protocol Requirements for Bandwidth Delegation .....57
6.2. Capability-Specific Procedures for Providing
Multicast Service .........................................57
6.2.1. Procedures for NAS-Initiated Multicast
Replication ........................................58
6.2.2. Procedures for Committed Bandwidth Reporting .......58
6.2.3. Procedures for Conditional Access and
Admission Control with Black and White Lists .......59
6.2.4. Procedures for Conditional Access and
Admission Control with Grey Lists ..................61
6.2.5. Procedures for Bandwidth Delegation ................63
6.3. Combinations of Multicast Capabilities ....................64
6.3.1. Combination of Conditional Access and
Admission Control with White and Black Lists
and Conditional Access and Admission Control
with Grey Lists ....................................64
6.3.2. Combination of Conditional Access and
Admission Control with Bandwidth Delegation ........65
6.3.3. Combination of NAS-Initiated Replication
with Other Capabilities ............................65
6.3.4. Combinations of Committed Bandwidth
Reporting with Other Multicast Capabilities ........66
7. Miscellaneous Considerations ...................................66
7.1. Report Buffering Considerations ...........................66
7.2. Congestion Considerations .................................67
8. Security Considerations ........................................67
9. IANA Considerations ............................................69
10. Acknowledgements ..............................................72
11. References ....................................................73
11.1. Normative References .....................................73
11.2. Informative References ...................................73
Appendix A. Example of Messages and Message Flows ................75
A.1. Provisioning Phase ........................................75
A.2. Handling Grey-Listed Flows ................................81
A.3. Handling White-Listed Flows ...............................87
A.4. Handling of Black-Listed Join Requests ....................92
A.5. Handling of Requests to Join and Leave the On-Line Game ...92
A.6. Example Flow for Multicast Flow Reporting .................95
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1. Introduction
[RFC5851] defines a framework and requirements for an Access Node
(AN) control mechanism between a Network Access Server (NAS) and an
Access Node (e.g., a Digital Subscriber Line Access Multiplexer
(DSLAM)) in a multi-service reference architecture in order to
perform QoS-related, service-related, and subscriber-related
operations. [RFC6320] specifies a protocol for Access Node Control
in broadband networks in line with this framework.
[RFC6320] supports, specifically for DSL access, three use cases
defined in [RFC5851]: the Topology Discovery use case, the Line
Configuration use case, and the Remote Connectivity Test use case.
However, it does not support the multicast use cases defined in
[RFC5851]. The present document specifies the extensions to the
Access Node Control Protocol required for support of these multicast
use cases. In addition, it supports the Committed Bandwidth
Reporting use case, described below. In terms of ANCP, these use
cases are organized into five capabilities:
o NAS-initiated multicast replication;
o conditional access and admission control with white and black
lists;
o conditional access and admission control with grey lists;
o bandwidth delegation; and
o committed bandwidth reporting.
NAS-initiated multicast replication assumes that multicast join and
leave requests are terminated on the NAS or that the NAS receives
requests to establish multicast sessions through other means (e.g.,
application-level signaling). The NAS sends commands to the AN to
start or stop replication of specific multicast flows on specific
subscriber ports. This use case is described briefly in the next-to-
last paragraph of Section 3.4 of [RFC5851].
Conditional access is described in Section 3.4.1 of [RFC5851].
Section 3.4.2.2 of [RFC5851] mentions a way in which conditional
access can be combined with admission control to allow best-effort
multicast flows, and Section 3.4.2.3 points out the necessary
conditions for using both conditional access and admission control.
In the case of "conditional access and admission control with white
and black lists", multicast join and leave requests are terminated at
the AN and accepted or ignored in accordance with the direction
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provided by white and black lists, respectively. The white and black
lists are provisioned per port at startup time and may be modified
thereafter. The NAS may combine conditional access with admission
control of white-listed flows by appropriate provisioning.
Conditional access and admission control with grey lists is similar
to conditional access and admission control with white lists, except
that before accepting any request matching a grey list entry, the AN
sends a request to the NAS for permission to replicate the flow.
Again, the NAS can enable admission control of grey-listed flows at
the AN.
Bandwidth delegation is described in Section 3.4.2.1 of [RFC5851].
It allows flexible sharing of total video bandwidth on an access line
between the AN and the NAS. One application of such bandwidth
sharing is where the AN does multicast admission control, while the
NAS or Policy Server does unicast admission control. In that case,
bandwidth delegation allows dynamic sharing of bandwidth between
unicast and multicast video traffic on each access line.
Committed bandwidth reporting is described in Section 3.4. The AN
reports the amount of multicast bandwidth it has granted to a given
access line each time that value changes. These reports may be
buffered for a NAS-provisionable interval so that reports for
multiple access lines can be bundled into the same message.
The formal specification of the behaviors associated with each of
these capabilities, singly and in combination, is given in Section 6.
In addition to the multicast service processing behavior just
sketched, the definition of each capability includes support for the
multicast accounting and reporting services described in
Section 3.4.3 of [RFC5851]. Because of this common content and
because of other protocol overlaps between the different
capabilities, the protocol descriptions for the multicast extensions
specified in this document are merged into a single non-redundant
narrative. Tables in Section 6 then indicate the specific sub-
sections of the protocol description that have to be implemented to
support each capability.
This document updates RFC 6320 by assigning capability type 3 to the
NAS-initiated multicast replication capability and by changing the
starting point for IANA allocation of result codes determined by IETF
Consensus from 0x100 to 0x64.
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1.1. A Note on Scope
The requirements in [RFC5851] were formulated with the IPTV
application in mind. Two basic assumptions underlie the use case
descriptions:
o that the Home Gateway operates in bridged mode, and
o that multicast signaling uses IGMP ([RFC2236] [RFC3376]) or
Multicast Listener Discovery (MLD) [RFC3810] rather than PIM
[RFC4601].
Without the first assumption the AN may lose sight of individual
subscriber devices making requests for multicast service. This has a
very minor effect on the capabilities described below but prevents
the application of per-device policies at the NAS. Changing the
second assumption would require that, in applications where the AN is
responsible for snooping IGMP and MLD, it now also monitors for PIM
signaling. The capabilities described in the present document do not
depend explicitly on what type of multicast signaling is used, but
the multiple phases of PIM setup could add complexity to their
implementation.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119].
This document uses the terms "connection admission control" ("CAC" or
simply "admission control") and "conditional access" as they are used
in [RFC5851].
The expression "delegated bandwidth" is used as a shorter way of
saying: "the total amount of video bandwidth delegated to the AN for
multicast admission control".
3. Multicast Use Cases
Quoting from [RFC5851]:
... the Access Node, aggregation node(s), and the NAS must all be
involved in the multicast replication process. This prevents
several copies of the same stream from being sent within the
access/aggregation network. In case of an Ethernet-based access/
aggregation network, this may, for example, be achieved by means
of IGMP snooping or IGMP proxy in the Access Node and aggregation
node(s).
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RFC 7256 ANCP Multicast Extensions July 2014
By introducing IGMP processing in the access/aggregation nodes,
the multicast replication process is now divided between the NAS,
the aggregation node(s), and Access Nodes. In order to ensure
backward compatibility with the ATM-based model, the NAS,
aggregation node, and Access Node need to behave as a single
logical device. This logical device must have exactly the same
functionality as the NAS in the ATM access/aggregation network.
The Access Node Control Mechanism can be used to make sure that
this logical/functional equivalence is achieved by exchanging the
necessary information between the Access Node and the NAS.
[RFC5851] describes the use cases for ANCP associated with such
multicast operations and identifies the associated ANCP requirements.
This section describes a subset of these use cases as background to
facilitate reading of this document, but the reader is referred to
[RFC5851] for a more exhaustive description of the ANCP multicast use
cases. Detailed example message flows can also be found in
Appendix A.
In the diagrams below, participation of the Home Gateway is optional,
depending on whether it is operating in bridged or routed mode. Note
that devices behind the Home Gateway may require the Home Gateway to
operate in routed mode to ensure that they can obtain access to non-
IPTV multicast services.
3.1. NAS-Initiated Multicast Replication Control Use Case
3.1.1. Goals
One option for multicast handling is for the subscriber to
communicate the join/leave information to the NAS. This can be done,
for instance, by terminating all subscriber IGMP ([RFC3376]) or MLD
([RFC2710] [RFC3810]) signaling on the NAS. Another example could be
a subscriber using some form of application-level signaling, which is
redirected to the NAS. In any case, this option is transparent to
the access and aggregation network. In this scenario, the NAS uses
ANCP to create and remove replication state in the AN for efficient
multicast replication. Thus, the NAS only sends a single copy of the
multicast stream towards the AN, which, in turn, performs replication
to multiple subscribers as instructed by the NAS via ANCP. The NAS
performs conditional access and admission control when processing
multicast join requests and only creates replication state in the AN
if admission succeeds.
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3.1.2. Message Flow
With the NAS-initiated use case, a Multicast Replication Control
message is sent by the NAS to the AN with a directive to either join
or leave one (or more) multicast flow(s). In the example message
flow, the AN uses a Generic Response message to convey the outcome of
the directive. Figure 1 illustrates such an ANCP message exchange as
well as the associated AN behavior.
+----------+ +-------+ +-----+ ANCP +-----+
|Subscriber| | Home | | AN |<-------------------->| NAS |
+----------+ |Gateway| +-----+ +-----+
| +-------+ | |
| | | (*)
| | | Multicast-Replication-Ctl |
| | | (Target, add, Flow 1) |
| | |<--------------------------|
| Mcast Flow 1 | |
|<===========+==============+ |
| | | Generic Response |
| | |-------------------------->|
| | | |
| | | |
~ ~ ~ ~
| | | |
| | | Multicast-Replication-Ctl |
| | | (Target,delete, Flow 1) |
| | |<--------------------------|
| | | |
| <Stop Replication of X |
| Mcast Flow 1> | Generic Response |
| | |-------------------------->|
(*) The NAS may optionally seek direction from an external
Authorization/Policy Server before admitting the flow.
Figure 1: NAS-Initiated Multicast Replication Control
3.2. Conditional Access and Admission Control Use Case
3.2.1. Goals
One option for multicast handling is for the access/aggregation nodes
to participate in IGMP/MLD processing (e.g., via IGMP/MLD snooping).
In this scenario, on detecting a join/leave request from an end user
for a multicast flow (in the grey list), the AN uses ANCP to request
a conditional access and admission control decision from the NAS. In
turn, after conditional access and admission control checks, the NAS
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uses ANCP to instruct the AN to change the replication states
accordingly.
3.2.2. Message Flow
For support of the conditional access and admission control use case,
on detection of an IGMP/MLD join request, the AN sends a Multicast
Admission Control message to the NAS to request a conditional access
and admission control check. In the case of a positive outcome, the
NAS sends a Multicast Replication Control message to the AN with a
directive to replicate the multicast flow to the corresponding user.
Similarly, on detection of an IGMP/MLD leave, a Multicast Admission
Control message is sent by the AN to the NAS to keep the NAS aware of
user departure for the flow. This message flow is illustrated in
Figure 2.
+----------+ +-------+ +-----+ ANCP +-----+
|Subscriber| | Home | | AN |<------------------->| NAS |
+----------+ |Gateway| +-----+ +-----+
| +-------+ | |
| | | |
| Join(Gr-Flow1) | Multicast-Admission-Crl |
|------------+---------->| (Target,add,Gr-Flow1) |
| | |-------------------------->|
| | | (*)
| | | Multicast-Replication-Crl |
| | | (Target,add,Gr-Flow1) |
| | |<--------------------------|
| Mcast Gr-Flow1 | |
|<===========+===========+ |
| | | |
~ ~ ~ ~
| | | |
| Leave(Gr-Flow1) | Multicast-Admission-Crl |
|------------+---------->| (Target,delete,Gr-Flow1) |
| | |-------------------------->|
| <Stop Replication of X |
| Mcast Gr-Flow1> | |
| | | |
Gr-Flow1: a multicast flow matching the grey list for that port
(*) The NAS may optionally seek direction from an external
Authorization/Policy Server before admitting the flow.
Figure 2: Multicast Conditional Access and Admission Control
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3.3. Multicast Flow Reporting Use Case
3.3.1. Goals
The multicast flow reporting use case allows the NAS to
asynchronously query the AN to obtain an instantaneous status report
related to multicast flows currently replicated by the AN.
3.3.2. Message Flow
The NAS sends a Multicast Flow Query Request message to the AN in
order to query the AN about information such as which multicast flows
are currently active on a given AN port or which ports are currently
replicating a given multicast flow. The AN conveys the requested
information to the NAS in a Multicast Flow Query Response message.
This message flow is illustrated in Figure 3.
+----------+ +-------+ +-----+ ANCP +-----+
|Subscriber| | Home | | AN |<---------->| NAS |
+----------+ |Gateway| +-----+ +-----+
| +-------+ | |
| | | Multicast Flow |
| | | Query Request |
| | |<------------------|
| | | |
| | | Multicast Flow |
| | | Query Response |
| | |------------------>|
| | | |
| | | |
Figure 3: Multicast Flow Reporting
3.4. Committed Bandwidth Reporting Use Case
3.4.1. Goals
The committed bandwidth reporting use case allows the NAS to maintain
current awareness of how much multicast bandwidth the AN has
committed to a given access line, so that the NAS can adjust its
forwarding scheduler to ensure the associated QoS. Note that this
involves a finer level of detail than provided by bandwidth
delegation, since the amount of delegated bandwidth is an upper limit
on the amount of bandwidth committed rather than an actual value. To
reduce the volume of messaging, reports from the AN may be buffered
so that one message reports on changes for multiple access lines.
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3.4.2. Message Flow
The message flow associated with this use case is shown in Figure 4.
The figure assumes that a non-zero buffering interval was previously
provisioned on the AN.
+-----+ +-------+ +-----+ ANCP +-----+
|Subs |+ | Home |+ | AN |<---------->| NAS |
|1,2 || |GW 1,2 || +-----+ +-----+
+-----+| +-------+| | |
+|----+ +|------+ | |
| | | | | |
| |Join(Subs1, Ch1) | |
|----------+--------------->| Start buffering |
| | | Multicast flow | timer. Create |
|<=========+================| message with |
| | | | | initial contents |
| | | | | reporting new |
| | | | | Subs1 bandwidth. |
| | Join(Subs2, Ch2) | |
| |----------+------------->| Add report for |
| | | Multicast flow | new Subs2 b/w. |
| |<=========+==============| |
| | | | | |
| |Leave(Subs1, Ch1) | |
|----------+--------------->| Replace report |
| | | | | for Subs1 with |
| | Stop replication X new value (which |
| | | | | happens to be |
| | | | | the same as the |
| | | | | starting value). |
| | | | | |
| | | | >|< TIMER expires |
| | | | | |
| | | | |Committed |
| | | | | Bandwidth Report |
| | | | |------------------>|
| | | | | (for latest |
| | | | | Subs1 and Subs2 |
| | | | | bandwidth) |
| | | | | |
Figure 4: Message Flow for Committed Bandwidth Reporting
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4. ANCP Messages
This section defines new ANCP messages and new usage of existing ANCP
messages as well as procedures associated with the use of these
messages.
Unless stated otherwise, receivers MUST ignore message contents that
are not supported by the set of capabilities negotiated between the
NAS and the Access Node.
4.1. Provisioning Message
Section 4.1 of [RFC6320] defines the Provisioning message that is
sent by the NAS to the AN to provision information in the AN.
The present document specifies that the Provisioning message MAY be
used by the NAS to provision multicast-related information (e.g.,
multicast service profiles). The ANCP Provisioning message payload
MAY contain:
o one or more instances of the Multicast-Service-Profile TLV. The
Multicast-Service-Profile TLV is defined in the present document
in Section 5.1. Each instance of the Multicast-Service-Profile
TLV contains a multicast service profile name and one or more list
actions. A list action consists of an action (add, delete,
replace), a list type (white, black, or grey), and list content
(multicast source and group addresses).
o an instance of the White-List-CAC TLV. The White-List-CAC TLV is
defined in Section 5.6. If present, this TLV indicates that the
AN is required to do admission control before replicating white-
listed flows.
o an instance of the MRepCtl-CAC TLV. The MRepCtl-CAC TLV is
defined in Section 5.7. If present, this TLV indicates that the
AN is required to do admission control before replicating flows
specified in Multicast Replication Control messages.
o an instance of the Report-Buffering-Time TLV. The Report-
Buffering-Time TLV is defined in Section 5.13. If present, this
TLV indicates Committed Bandwidth Report messages should be
buffered for the amount of time given by the TLV before being
transmitted to the NAS.
See Section 6 for information on which multicast capabilities require
support of these TLVs in the Provisioning message.
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4.1.1. Sender Behavior
When directed by the Policy Server or by management action, the NAS
sends the Provisioning message to initially provision or to update
the white, black, and/or grey multicast channel lists associated with
a set of named multicast service profiles or to direct the AN to
perform admission control for specific classes of flows.
To provision or update a multicast service profile, the NAS MUST
include within the message one or more instances of the Multicast-
Service-Profile TLV specifying the content to be provisioned or
updated. The NAS MUST NOT include any list type (white, black, or
grey) that is not supported by the set of multicast capabilities
negotiated between the NAS and the AN. The NAS MUST NOT use the
Provisioning message to send instances of the Multicast-Service-
Profile TLV to the AN unless the Multicast-Service-Profile TLV is
supported by the set of multicast capabilities negotiated between the
NAS and the AN.
To require admission control to be performed at the AN on white-
listed flows, the NAS MUST include a copy of the White-List-CAC TLV
in the Provisioning message. The White-List-CAC TLV MUST NOT be
provided unless the negotiated set of capabilities includes
conditional access and admission control with white and black lists.
To require admission control to be performed at the AN on grey-listed
flows or on NAS-initiated flows, the NAS MUST include a copy of the
MRepCtl-CAC TLV in the Provisioning message. The MRepCtl-CAC TLV
MUST NOT be provided unless the negotiated set of capabilities
includes NAS-initiated multicast replication or conditional access
and admission control with grey lists.
To require buffering of Committed Bandwidth Report messages so that
reports for multiple access lines can be included in the same
message, the NAS MUST include a copy of the Report-Buffering-Time TLV
containing a non-zero time value in a Provisioning message sent to
the AN. The Report-Buffering-Time TLV MUST NOT be provided unless
the negotiated set of capabilities includes committed bandwidth
reporting.
4.1.2. Receiver Behavior
The receiving AN provisions/updates the white, black, and/or grey
lists associated with the multicast service profile names contained
in the Multicast-Service-Profile TLV instances within the message
according to the contents of the associated List-Action TLVs. The AN
MUST process List-Action TLVs in the order in which they appear
within the message. In keeping with the general rule stated in
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Section 4, the AN MUST ignore instances of the List-Action TLV
referring to any list type (white, black, or grey) that is not
supported by the set of multicast capabilities negotiated between the
NAS and the AN.
When a new multicast service profile is identified by a Multicast-
Service-Profile TLV, the initial state of all lists associated with
that profile according to the negotiated set of multicast
capabilities is empty until changed by the contents of Multicast-
Service-Profile TLVs.
The receipt of a Provisioning message containing updates to an
existing multicast service profile subsequent to startup will cause
the AN to review the status of active flows on all ports to which
that profile has been assigned. For further details, see Section 6.
If the White-List-CAC and/or MRepCtl-CAC TLV is present in the
Provisioning message and the respective associated capabilities have
been negotiated, the AN prepares (or continues) to do admission
control on the indicated class(es) of flow. If one or both of these
TLVs was present in an earlier Provisioning message but is absent in
the latest message received, the AN ceases to do admission control on
the indicated class(es) of flow.
The buffering time specified in an instance of the Report-Buffering-
Time TLV will not be applied until the current accumulation process
of Committed Bandwidth Report messages finishes.
As indicated in [RFC6320], the AN MUST NOT reply to the Provisioning
message if it processed it successfully. If an error prevents
successful processing of the message content, the AN MUST return a
Generic Response message as defined in [RFC6320], containing a
Status-Info TLV with the appropriate content describing the error.
For this purpose, the presence of a list type in a Multicast-Service-
Profile TLV, which was ignored because it was not supported by the
negotiated set of capabilities, is not considered to be an error.
4.2. Port Management Message
As specified in [RFC6320], the NAS may send DSL line configuration
information to the AN (ANCP-based DSL line configuration use case)
using ANCP Port Management messages. See Section 7.3 of [RFC6320]
for the format of the Port Management message in that usage.
This document specifies that the Port Management message MAY be used
to convey either or both of the following TLVs:
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o Multicast-Service-Profile-Name TLV (defined in Section 5.2). This
TLV associates a Multicast Service Profile with the access line
specified by the extension block and, in the case of white and
black lists, delegates conditional access to the AN for the
specified access line and channels.
o Bandwidth-Allocation TLV (defined in Section 5.5). This TLV
specifies the total multicast bandwidth available to the AN for
admission control at the access line.
When the Port Management message is used for this purpose:
o the Function field in the Port Management message MUST be set to
8, "Configure Connection Service Data".
o the message MUST include TLV(s) to identify the access line
concerned. If the access line is a DSL loop, the line-identifying
TLV(s) MUST be as specified in Section 5.1.2 of [RFC6320]. For
non-DSL access lines, the appropriate alternative line-identifying
TLV(s) MUST be present. Line configuration data other than the
two TLVs listed in the previous paragraph MAY be present.
4.2.1. Sender Behavior
The NAS sends the Port Management message at startup time to
initialize parameters associated with the access line specified in
the message and with the multicast capabilities negotiated between
the NAS and the AN. The NAS MAY send additional Port Management
messages subsequent to startup, to update or, in the case of the
Bandwidth-Allocation TLV, reset these parameters. If the NAS
includes a Multicast-Service-Profile-Name TLV in the Port Management
message, the name MUST match a profile name provided in a Multicast-
Service-Profile TLV in a prior Provisioning message. The NAS MUST
NOT include a TLV unless it is supported by the set of multicast
capabilities negotiated between the NAS and the AN. See Section 6
for further information.
4.2.2. Receiver Behavior
If the Port Management message contains a Multicast-Service-Profile-
Name TLV, the AN associates the named profile with the specified
access line. This association replaces any previous association.
That is, a given access line is associated with at most one multicast
service profile. The replacement of one multicast service profile
with another will cause the AN to review the status of all active
flows on the target port. For further details see Section 6.
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If the Port Management message contains a Bandwidth-Allocation TLV,
the AN adopts this as the current value of its total multicast
bandwidth limit for the target port. If the AN has already committed
multicast bandwidth exceeding the amount given in the Bandwidth-
Allocation TLV, the AN SHOULD NOT discontinue any multicast streams
in order to bring bandwidth down to within the new limit, unless such
action is required by local policy. However, the AN MUST NOT admit
new multicast streams that are subject to admission control until it
can do so within the limit specified by the Bandwidth-Allocation TLV.
If the Port Management request cannot be processed due to error and
the Result field of the request is Nack (0x1) or AckAll (0x2), the AN
SHOULD add a Status-Info TLV to the Extension Value field in its
reply if this will provide useful information beyond what is provided
by the Result Code value returned in the response header. In
particular, if the name within the Multicast-Service-Profile-Name TLV
does not match a profile name given in a prior Provisioning message,
the AN SHOULD return a reply where the Result Code field in the
header indicates 0x55, "Invalid TLV contents", the Error Message
field in the Status-Info TLV contains the text "Multicast profile
name not provisioned", and the Status-Info TLV contains a copy of the
Multicast-Service-Profile-Name TLV.
4.3. Multicast Replication Control Message
This section defines a new message called the Multicast Replication
Control message. The Multicast Replication Control message is sent
by the NAS to the AN with one or more directives to add (join) or
delete (leave) a multicast flow on a target object identified in the
content of the message.
The Message Type for the Multicast Replication Control message is
144.
The ANCP Multicast Replication Control message payload contains the
following TLVs:
o Target TLV: The Target TLV is defined in Section 4.3 of [RFC6320].
It MUST appear once and only once. It is encoded as specified in
[RFC6320] or extensions and identifies the AN port subject to the
request for admission or release.
o Command TLV: The Command TLV is defined in Section 4.4 of
[RFC6320]. It MUST be present. It MAY appear multiple times.
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As [RFC6320] indicates, the contents of the Command Info field within
the Command TLV are specific to the message in which the TLV occurs.
For the Multicast Replication Control message, these contents consist
of:
o a Command Code field;
o an Accounting field; and
o an instance of the Multicast-Flow TLV.
Figure 5 illustrates the complete Command TLV with the contents
specific to the Multicast Replication Control message.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Command 0x0011 | Command TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Command Code | Accounting | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast-Flow TLV |
| ... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Other embedded TLV Type | Other embedded TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Other embedded TLV data ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Contents of the Command TLV in the Multicast Replication
Control Message
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o Command Code: One of the following command directives:
1 "Add"
2 "Delete"
3 "Delete All"
4 "Admission Control Reject"
5 "Conditional Access Reject"
6 "Admission Control and Conditional Access Reject"
Directives 4 through 6 are used as described in Section 4.4.2.
o Accounting: Meaningful only when the Command Code is "Add" (1).
In that case, 0 indicates flow accounting is disabled, and 1
indicates that octet accounting for the flow is requested. The
sender MUST set the Accounting field to 0, and the receiver MUST
ignore the Accounting field for other Command Code values.
o Reserved: Reserved for future use. MUST be set to zeroes by the
sender and ignored by the receiver.
o Multicast-Flow TLV: An instance of the Multicast-Flow TLV
(Section 5.12) specifying the flow to be added or deleted. The
Multicast-Flow TLV is omitted if the Command Code has value
"Delete All" (3).
o Other embedded TLV data: No other embedded TLVs are currently
specified within the Multicast Replication Control message and
Command TLV. However, see the description of the Multicast
Admission Control message (Section 4.4). Unrecognized embedded
TLVs SHOULD be silently discarded.
The figure below is an example of a Multicast Replication Control
message that would result in a swap from multicast Source-Specific
Multicast (SSM) flows 2001:DB8::1, FF34::2 to 2001:DB8::2, FF34::3 on
the target identified by the Access Loop Circuit ID:
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1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (0x880C) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | MsgType=144 | Res=2 | Result Code = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier = 18 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I| SubMessage Number | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Access Loop Circuit ID ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Command 0x0011 | Command TLV Length = 44 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cmd Code = 2 | Acctg = 0 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = Multicast-Flow 0x0019 | TLV Length = 36 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow Type = 2 | AddrFam = 2 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Multicast Group Address ~
| = FF34::2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Source Address ~
| = 2001:DB8::1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Command 0x0011 | Command-TLV Length = 44 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cmd Code = 1 | Acctg = 1 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = Multicast-Flow 0x0019 | TLV Length = 36 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow Type = 2 | AddrFam = 2 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Multicast Group Address ~
| = FF34::3 |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Source Address ~
| = 2001:DB8::2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Example Change of Source Flow Using Multicast Replication
Control Message
4.3.1. Sender Behavior
The NAS MAY issue a Multicast Replication Control message to the AN
to convey one or more directives to add (join) or delete (leave) one
or more multicast flows.
The NAS MAY send this message on its own initiative to support the
NAS-initiated multicast control use case presented in [RFC5851] and
summarized in Section 3.1. In that case, the NAS MUST set the Result
field to AckAll (0x2) or Nack (0x1) according to its requirements.
The NAS MAY also send this message in response to a Multicast
Admission Control message (defined in Section 4.4) received from the
AN to support the conditional access and admission control use case
presented in [RFC5851] and summarized in Section 3.2. In that case,
the NAS MUST set the Result field to Nack (0x1).
In either case, the sender MUST populate the Result Code field with
the value 0 and the ANCP Transaction Identifier field with a unique
value, as described in Section 3.6.1.6 of [RFC6320].
Each Multicast Replication Control message MUST contain one or more
commands, each encapsulated in its own Command TLV. The sender MUST
use a separate Command TLV for each distinct multicast flow.
When the order of processing of two commands does not matter, the
commands MUST be transmitted in separate Multicast Replication
Control messages.
4.3.2. Receiver Behavior
When successive commands (in the same or different messages) relate
to the same target and multicast flow, the state of each feature
controlled or affected by attributes received in the Multicast
Replication Control message SHALL be as set by the last command or
message referring to that target and flow and containing the
controlling attribute. As an example, successive Multicast
Replication Control messages containing add commands for a given port
and flow but differing only in the Accounting field update the state
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of the accounting feature to what is set in the final command
received, but all other features are unaffected by the second
message.
If more than one Command TLV is present in a Multicast Replication
Control message, the AN MUST act on the commands in the order in
which they are presented in the message. The AN SHALL assign a
sequence number to each command in a given Multicast Replication
Control message, starting from 1 for the first command.
If a Command TLV adds one or more flows and the AN is performing
admission control for Multicast Replication Control messages, then
the AN MUST perform admission control before replicating the flows.
If the admission control check fails, the AN MUST treat the failure
as an error as described below. The appropriate Result Code value
for the response is 0x13 "Out of resources".
If the AN processes the complete Multicast Replication Control
message successfully and the Result field of the Multicast
Replication Control message was set to AckAll (0x2), the AN MUST
respond with a Generic Response message where the Result field is set
to Success (0x3), the Result Code field is set to 0, and the
Transaction Identifier field is copied from the Multicast Replication
Control message. The body of the response MAY be empty or MAY be
copied from the Multicast Replication Control message.
If the AN processes the complete Multicast Replication Control
message successfully and the Result field of the Multicast
Replication Control message was set to Nack (0x1), the AN MUST NOT
respond to the message.
The processing/execution of multiple commands contained in a single
Multicast Replication Control message MUST be interrupted at the
first error encountered and the remaining commands in the Multicast
Replication Control message discarded. Similarly, if a given command
specifies multiple Single-Source Multicast (SSM) flows and an error
occurs, processing MUST be interrupted at that point, and the
remainder of the Command TLV discarded.
If the AN detects an error in a received Multicast Replication
Control message and the Result field in that message was set to Nack
(0x1) or AckAll(0x2), the AN MUST generate a Generic Response message
providing error information to the NAS. This specification
identifies the following new Result Code values beyond those
specified in [RFC6320], which MAY be used in a Generic Response sent
in reply to a Multicast Replication Control message:
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0x64 Command error.
Where detected: ANCP agent at the AN.
Further description: an invalid command code has been received.
Required additional information in the message: see below.
Target: ANCP agent at the NAS.
Action RECOMMENDED for the receiving ANCP agent: Report the
error to the control application with an indication of the
erroneous information associated with the invalid TLV(s).
0x65 Invalid flow address.
Where detected: ANCP agent at the AN.
Further description: either inconsistent flow address
information has been provided or the address family is
unsupported.
Required additional information in the message: see below.
Target: ANCP agent at the NAS.
Action RECOMMENDED for the receiving ANCP agent: Report the
error to the control application with an indication of the
erroneous information associated with the invalid TLV(s).
0x66 Multicast flow does not exist.
Where detected: control application at the AN.
Further description: the NAS has attempted to delete a flow
that is not active on the given access line.
Required additional information in the message: see below.
Target: control application at the NAS.
Action RECOMMENDED for the receiving ANCP agent: report the
error to the control application with an indication of the
erroneous information associated with the invalid TLV(s).
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A Generic Response message responding to the Multicast Replication
Control message and containing one of the above Result Code values
MUST include a Status-Info TLV, which includes one or two embedded
TLVs as follows:
o a Sequence-Number TLV as described in Section 5.4, giving the
sequence number of the failed command, MUST be included; and
o the failed Command TLV itself SHOULD be included.
Note: The Error Message field of the Status-Info TLV MAY be used
to report more details than implied by the Result Code value in
the message header. For example, the Result Code value could be
0x65, and the Error Message field could contain the text: "Source
address present for ASM flow".
4.4. Multicast Admission Control Message
This section defines a new message called the Multicast Admission
Control message. The Multicast Admission Control message is sent by
the AN to the NAS to request admission of a multicast flow, or to
notify of the removal of a multicast flow, for a given target.
The Message Type for the Multicast Admission Control message is 145.
The ANCP Multicast Admission Control message payload contains two
TLVs:
o Target TLV: The Target TLV is defined in [RFC6320]. It MUST
appear once and only once in the Multicast Admission Control
message. It is encoded as specified in [RFC6320] or extensions
and identifies the AN port subject to the request for admission or
release.
o Command TLV: The Command TLV is defined in [RFC6320]. It MUST be
present. If it appears more than once, only the first instance is
considered meaningful in the present version of this
specification, and the other instances are ignored.
Note: In the future, the specification of the Multicast Admission
Control message may be extended to allow transport of more than a
single directive (e.g., to carry both a leave from one group and a
join to another group for the same target). It is expected that
this would support a similar notion of strict sequenced processing
as currently defined for handling multiple directives in the
Multicast Replication Control message whereby all directives
following the first directive that cannot be executed are not
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executed either. When the strict sequenced processing of the
directives is not required, the directives are distributed across
separate messages.
The Command TLV has the same contents as were described above for the
Multicast Replication Control message, with the following additions:
o A Request-Source-IP TLV MAY be appended to the Command TLV as an
additional embedded TLV.
o Similarly, a Request-Source-MAC TLV MAY be appended to the Command
TLV as an additional embedded TLV.
o Finally and preferably, a Request-Source-Device-Id TLV MAY be
appended to the Command TLV as an additional embedded TLV.
Note that the Command TLV length includes the length of any embedded
TLVs, including the embedded TLV headers.
4.4.1. Sender Behavior
The AN sending the Multicast Admission Control message MUST set the
Result field to Ignore (0x0).
The AN MUST populate the ANCP Transaction Identifier field with a
unique value, as described in Section 3.6.1.6 of [RFC6320].
The AN MUST encode the Command TLV as specified in Section 4.3 with
the following additional rules:
o The Accounting field MUST be set to 0.
o The Command Code field MUST be set to "Add" (1) when the message
conveys a join request, to "Delete" (2) when the message conveys a
leave, and to "Delete All" (3) when the message conveys a leave of
all channels (on the target).
o The Multicast-Flow TLV within the Command TLV identifies the
multicast flow subject to the request for admission or release.
When the Command Code is 3, the Multicast-Flow TLV is omitted.
o The Request-Source-IP embedded TLV MAY be included by the AN to
convey the IP address of the sender of the join/leave message
(e.g., IGMP/MLD join/leave) that triggered the AN to include the
corresponding Command TLV in the Multicast Admission Control
message. If it appears more than once, only the first instance is
considered meaningful, and the other instances are ignored.
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o The Request-Source-MAC embedded TLV MAY be included by the AN to
convey the Media Access Control (MAC) address of the sender of the
join/leave message (e.g., IGMP/MLD join/leave) that triggered the
AN to include the corresponding Command TLV in the Multicast
Admission Control message. If it appears more than once, only the
first instance is considered meaningful, and the other instances
are ignored.
o As a third alternative, the Request-Source-Device-Id embedded TLV
MAY be included by the AN to convey a local identifier of the
sender of the join/leave message (e.g., IGMP/MLD join/leave) that
triggered the AN to include the corresponding Command TLV in the
Multicast Admission Control message. If it appears more than
once, only the first instance is considered meaningful, and the
other instances are ignored.
The inclusion of Request-Source-IP or Request-Source-MAC in the
Multicast Admission Control message is typically done to allow the
application of policies applicable to specific devices within the
customer's network. However, transmission of either of these fields
beyond the AN introduces potential privacy issues. Instead of
transmitting either of these identifiers, it is RECOMMENDED that the
AN map the required identifier to a local value known to the AN and
Authentication, Authorization, and Accounting (AAA) but not to the
NAS, as discussed in Section 8. The local identifier is transmitted
using the Request-Source-Device-Id TLV.
4.4.2. Receiver Behavior
On receipt of a Multicast Admission Control message:
o The NAS MUST ignore the Result field.
o If the directive in the Multicast Admission Control message is
"Delete" (2) or "Delete All" (3) and is processed correctly by the
NAS, the NAS MUST NOT generate any ANCP message in response to the
Multicast Admission Control message.
o If the directive in the Multicast Admission Control message is
"Add" (1) and is accepted by the NAS, the NAS MUST generate a
Multicast Replication Control message in response to the Multicast
Admission Control message. The Multicast Replication Control
message:
* MUST contain a Result set to Nack (0x1);
* MUST contain a Transaction ID with a unique value, as described
in Section 3.6.1.6 of [RFC6320]; and
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* MUST contain the directive as accepted by the NAS. The NAS MAY
modify the Accounting field if flow accounting is required.
o If the directive in the Multicast Admission Control message is
"Add" (1) and is processed correctly but not accepted by the NAS
(i.e., it does not pass the conditional access and admission
control check), the NAS MAY generate a Multicast Replication
Control message in response to the Multicast Admission Control
message. This optional message can be used by the AN to maintain
statistics about admission control rejections. When used in this
situation, the Multicast Replication Control message:
* MUST contain a Result set to 0x0;
* MUST contain a Transaction ID with a unique value, as described
in Section 3.6.1.6 of [RFC6320]; and
* MUST contain the directive rejected by the NAS (i.e., Target
TLV and Command TLV) but with a Command Code set to "Admission
Control Reject" (4), "Conditional Access Reject" (5), or
"Admission Control and Conditional Access Reject" (6) as
applicable.
o If the Multicast Admission Control message cannot be processed
correctly by the NAS (e.g., the message is malformed, the
multicast flow does not exist, etc.), the NAS MUST generate a
Generic Response message (defined in Section 4.2 of [RFC6320])
with appropriate content indicating the reason for the failure.
4.5. Bandwidth Reallocation Request Message
The Bandwidth Reallocation Request message is used when the bandwidth
delegation capability is included in the negotiated set. It MAY be
sent either by the NAS or by the AN to request an adjustment in the
amount of delegated bandwidth. It will be sent by the NAS typically
to reduce the multicast bandwidth allocated to the AN in order for
the NAS to satisfy a request to add one or more flows. Conversely,
the AN will send a Bandwidth Reallocation Request message to obtain
additional bandwidth to satisfy a request to add a multicast channel.
In each case, the requestor has a minimum requirement for additional
bandwidth and MAY ask for additional bandwidth beyond this amount
(e.g., to handle anticipated future requests).
The Bandwidth Reallocation Request message contains two TLVs:
o the Target TLV (Section 4.3 of [RFC6320] or an extension),
specifying a single access line; and
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o the Bandwidth-Request TLV (Section 5.8), specifying the required
and preferred amounts of delegated bandwidth.
The Message Type for the Bandwidth Reallocation Request message is
146.
4.5.1. Sender Behavior
The Result field in the header of the Bandwidth Reallocation Request
message is not used, and the sender MUST set it to Ignore (0x0).
The bandwidth values in the Bandwidth-Request TLV are expressed in
terms of total multicast bandwidth allocated to the AN.
Note: The choice of "total bandwidth" rather than "incremental
bandwidth" was made so that it would be easier for the AN and NAS
to keep their respective views of the current amount of delegated
bandwidth synchronized.
Because the values are totals rather than desired increments/
decrements, the relationship between the required amount and the
preferred amount will differ depending on whether the Bandwidth
Reallocation Request message is issued by the NAS or the AN.
o If the NAS is making the request, the preferred amount MUST be
less than or equal to the required amount. The required amount
MUST be less than the current amount of delegated bandwidth.
o If the AN is making the request, the preferred amount MUST be
greater than or equal to the required amount. The required amount
MUST be greater than the current amount of delegated bandwidth.
4.5.2. Receiver Behavior
When the peer receives a valid Bandwidth Reallocation Request
message, it SHOULD determine whether it can satisfy the request from
its existing allocation of unused video bandwidth. If it decides
that it can reallocate bandwidth to the peer, it MAY choose to return
any amount between the required and the preferred amounts indicated
in the Bandwidth Reallocation Request message.
The peer MUST return a Bandwidth Transfer message (Section 4.6)
indicating its decision. If the request is met, the Result field of
the Bandwidth Transfer message MUST be set to Success (0x3), the
Result Code field MUST be set to 0x000, and the Bandwidth-Allocation
TLV (Section 5.5) MUST contain the new value of total multicast
bandwidth. This new value MUST lie between the required and
preferred values, inclusive, from the request message. If the
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request is not met, the Result field of the Bandwidth Transfer
message MUST be set to Failure (0x4), the Result Code field MUST be
set to 0, and the Bandwidth-Allocation TLV MUST contain the value of
the currently allocated amount of delegated bandwidth as the
responder views it.
The following cases indicate that the sender holds a different view
of the amount of delegated bandwidth from the receiver:
o The NAS receives a request where the required amount is less than
its view of the current amount of delegated bandwidth.
o The AN receives a request where the required amount is greater
than its view of the current amount of delegated bandwidth.
If one of these cases occurs, the receiver, with one exception, MUST
send a Bandwidth Transfer message indicating Success.
o If the NAS received the request, the allocated amount in the NAS's
response MUST be at least equal to the NAS's view of the current
amount of delegated bandwidth.
o If the AN received the request, the allocated amount in the AN's
response MUST be no greater than the AN's view of the current
amount of delegated bandwidth.
The exception is when the NAS receives a request while it has a
request of its own outstanding. Handling of that case is described
below.
Note: While the cases just described are an error condition, the
success response achieves a graceful recovery.
To avoid deadlock due to race conditions, the following rules MUST be
applied:
a. If the NAS receives a Bandwidth Reallocation Request message
while it has a Bandwidth Reallocation Request message of its own
outstanding for the same access line, the NAS MUST provide an
immediate failure response to the request from the AN, with a
Result Code value set to 0x68 "Inconsistent views of delegated
bandwidth amount" or 0x69 "Bandwidth request conflict" as
applicable. (See below for more information).
b. If the AN receives a Bandwidth Reallocation Request message while
it has a Bandwidth Reallocation Request message of its own
outstanding for the same access line, the AN MUST release any
bandwidth it has already committed to an outstanding join request
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while it is awaiting a response from the NAS. It MUST decide
upon and send its response to the NAS taking the released
bandwidth into account.
If the receiver is unable to process the Bandwidth Reallocation
Request message due to an error, then the receiver MUST return a
Bandwidth Transfer message where:
o the Result field is set to Failure (0x4),
o the Result Code field is set appropriately to indicate the type of
error that was detected,
o the Bandwidth-Allocation TLV contains the value of the current
amount of delegated bandwidth as the responder views it, and
o a Status-Info TLV MAY follow the Bandwidth-Allocation TLV giving
further information about the error.
This specification provides three new Result Code values applicable
specifically to the contents of the Bandwidth-Request TLV. These
Result Code values by their nature MUST only be used when the error
is being reported in a Bandwidth Transfer message rather than a
Generic Response message.
0x67 Invalid preferred bandwidth amount.
Where detected: control application at the receiver of the
Bandwidth Reallocation Request message.
Further description: the preferred and required amounts of
bandwidth in the TLV do not have the numerical relationship
described above.
Required additional information in the message: as described
above.
Target: control application at the sender of the Bandwidth
Reallocation Request message.
Action RECOMMENDED for the receiving ANCP agent: report the
error to the control application with the returned value of the
Bandwidth-Allocation TLV. See also Section 4.6.2.2.
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0x68 Inconsistent views of delegated bandwidth amount.
Where detected: control application at the NAS.
Further description: the NAS has an outstanding Bandwidth
Reallocation Request, so it is rejecting a similar request from
the AN. In the AN request, the required amount was less than
the NAS's view of the current amount of delegated bandwidth.
Required additional information in the message: as described
above.
Target: control application at the AN.
Action RECOMMENDED for the receiving ANCP agent: report the
error to the AN control application with the returned value of
the Bandwidth-Allocation TLV. See also Section 4.6.2.2.
0x69 Bandwidth request conflict.
Where detected: control application at the NAS.
Further description: the NAS has an outstanding Bandwidth
Reallocation Request, so it is rejecting a similar, valid
request from the AN.
Required additional information in the message: as described
above.
Target: control application at the AN.
Action RECOMMENDED for the receiving ANCP agent: report the
error to the AN control application with the returned value of
the Bandwidth-Allocation TLV. See also Section 4.6.2.2.
4.6. Bandwidth Transfer Message
The Bandwidth Transfer message is used to transfer video bandwidth
from the sender to the peer for a specific access line. This message
MAY be sent either from the AN or from the NAS. As described in the
previous section, it is the required response to a valid Bandwidth
Reallocation Request message.
The Bandwidth Transfer message MAY also be used to transfer bandwidth
autonomously from one peer to another. One example of this usage is
to release bandwidth borrowed earlier by means of the Bandwidth
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Reallocation Request message. When the message is used in this way,
the Result field in the Bandwidth Transfer message MUST be set to
Ignore (0x0).
Note: This allows the receiver to distinguish between an
autonomous transfer and a response to a previous Bandwidth
Reallocation Request message, for purposes of validation.
The Message Type for the Bandwidth Transfer message is 147. The
Bandwidth Transfer message contains the following TLVs:
o the Target TLV, designating the access line concerned;
o an instance of the Bandwidth-Allocation TLV (Section 5.5). The
bandwidth value in the Bandwidth-Allocation TLV is the new amount
of delegated bandwidth allocated to the target.
4.6.1. Sender Behavior
When sending a Bandwidth Transfer message where the Result value is
Ignore (0x0) or Success (0x3), the following relationships MUST hold:
o If the message is sent by the NAS, the bandwidth value in the
Bandwidth-Allocation TLV MUST be greater than or equal to the
sender's view of the current amount of delegated bandwidth for the
access line concerned.
o If the message is sent by the AN, the bandwidth value in the
Bandwidth-Allocation TLV MUST be less than or equal to the
sender's view of the current amount of delegated bandwidth for the
access line concerned.
Further sender behavior is specified above, in Section 4.5.2.
4.6.2. Receiver Behavior
4.6.2.1. Behavior of the NAS
If the amount of delegated bandwidth provided in the Bandwidth-
Allocation TLV is not greater than the NAS's view of the current
amount of delegated bandwidth, the NAS MUST update its view of the
current amount of delegated bandwidth to the amount indicated in the
Bandwidth Transfer message. This is required regardless of whether
the Result field of that message indicates Success or Failure.
If the amount of delegated bandwidth provided in the Bandwidth-
Allocation TLV is greater than the NAS's view of the current amount
of delegated bandwidth, the NAS MAY accept the given value as its new
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value of delegated bandwidth. Alternatively, the NAS MAY force the
AN to modify its view of the amount of delegated bandwidth to that
held by the NAS by sending a Port Management message for the target
access line concerned that contains a Bandwidth-Allocation TLV with a
value equal to the amount of delegated bandwidth the NAS wishes to
enforce.
4.6.2.2. Behavior of the AN
If the amount of delegated bandwidth provided in the Bandwidth-
Allocation TLV of the Bandwidth Transfer message differs from the
AN's view of the current amount of delegated bandwidth, the AN MUST
update its view of the current amount of delegated bandwidth to the
amount indicated in the Bandwidth Transfer message. This is required
with the exception of a Bandwidth Transfer message with a Result
field equal to Failure (0x4) and a Result Code field equal to 0x68
"Inconsistent views of delegated bandwidth amount" or 0x69 "Bandwidth
request conflict". If Result Code value 0x68 is received, the AN
MUST issue a Delegated Bandwidth Query Request message to determine
the NAS's current view of the amount of delegated bandwidth. The AN
MUST update its own view based on the value returned in the Delegated
Bandwidth Query Response message. If Result Code value 0x69 is
received, the AN SHOULD carry out this procedure unless it can
account for the discrepancy as a result of a transfer of bandwidth to
the NAS that was carried out just before the incoming Bandwidth
Transfer message was processed.
Note: The two Result Code values indicate a race condition where
the AN may have just completed a transfer of bandwidth to the NAS.
As a result, the value given in the Bandwidth Transfer message may
be outdated, and the AN needs to query the NAS to find its latest
view. The procedure assumes that ordering is preserved between
the Bandwidth Transfer message sent by the AN in response to the
NAS's request and the subsequent Delegated Bandwidth Query Request
message.
If the AN has already committed multicast bandwidth exceeding the
amount given in the Bandwidth-Allocation TLV, the AN SHOULD NOT
discontinue any multicast streams in order to bring bandwidth down to
within the new limit, unless such action is required by local policy.
However, the AN MUST NOT admit new multicast streams that are subject
to admission control until it can do so within the limit specified by
the Bandwidth-Allocation TLV. As specified in Section 6.2.5.2, the
AN MAY attempt to correct the situation by sending a request to the
NAS for an increased allocation of delegated bandwidth using the
Bandwidth Reallocation Request message.
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4.7. Delegated Bandwidth Query Request Message
The Message Type for the Delegated Bandwidth Query Request (and
Response) messages is 148.
The Delegated Bandwidth Query Request message MAY be sent either by
the NAS or by the AN to retrieve the peer's view of the amount of
delegated bandwidth. The request contains one TLV:
o a Target TLV designating the access line for which the information
is requested.
4.7.1. Sender Behavior
The sender MUST set the Result field in the header of the Delegated
Bandwidth Query Request message to AckAll (0x2). The Result Code
value MUST be set to 0. The sender MUST populate the ANCP
Transaction Identifier field with a unique value, as described in
Section 3.6.1.6 of [RFC6320].
4.7.2. Receiver Behavior
If the AN or NAS receives a valid Delegated Bandwidth Query Request
message, it MUST respond with a Delegated Bandwidth Query Response
message. The Result field in the header of the response MUST be set
to Success (0x3). The Result Code field MUST be set to 0. The
Transaction Identifier field MUST be copied from the request message.
The body of the response MUST contain the Target TLV, copied from the
request message. Finally, the body of the response MUST contain a
Bandwidth-Allocation TLV, containing the current amount of delegated
bandwidth from the point of view of the receiver of the request.
If the contents of the Delegated Bandwidth Query Request message are
in error, the receiver MUST return a Delegated Bandwidth Query
Response message with the Result field in the header set to Failure
(0x3). The Result Code field MUST be set to the value that indicates
the nature of the error (e.g., 0x500 "One or more of the specified
ports do not exist"). The Transaction Identifier field MUST be
copied from the request. The body of the response MUST contain the
Target TLV copied from the request. This MAY be followed by a
Status-Info TLV giving further information about the error.
4.8. Delegated Bandwidth Query Response Message
The Delegated Bandwidth Query Response message is sent in reply to a
Delegated Bandwidth Query Request message. The response to a valid
request contains two TLVs:
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o the Target TLV, copied from the request; and
o a Bandwidth-Allocation TLV, giving the responder's view of the
current amount of multicast bandwidth delegated to the AN.
The Message Type for the Delegated Bandwidth Query Response message
is 148.
4.8.1. Sender Behavior
Sender behavior for the Delegated Bandwidth Query Response message is
specified in Section 4.7.2.
4.8.2. Receiver Behavior
If the Delegated Bandwidth Query Response message indicates Success
(0x3), the actions described in Sections 4.8.2.1 and 4.8.2.2 apply.
4.8.2.1. Behavior at the NAS
If the amount of delegated bandwidth provided in the Bandwidth-
Allocation TLV is less than the NAS's view of the current amount of
delegated bandwidth, the NAS MUST update its view of the current
amount of delegated bandwidth to the amount indicated in the
Delegated Bandwidth Query Response message.
If the amount of delegated bandwidth provided in the Bandwidth-
Allocation TLV is greater than the NAS's view of the current amount
of delegated bandwidth, the NAS MAY accept the given value as its new
value of delegated bandwidth. Alternatively, the NAS MAY force the
AN to modify its view of the amount of delegated bandwidth to that
held by the NAS by sending a Port Management message for the target
access line concerned that contains a Bandwidth-Allocation TLV with a
value equal to the amount of delegated bandwidth the NAS wishes to
enforce.
4.8.2.2. Behavior at the AN
The AN SHOULD accept the value returned in the Bandwidth-Allocation
TLV of the Delegated Bandwidth Query Response message as the correct
value of the current amount of delegated bandwidth. If the AN has
already committed multicast bandwidth exceeding the amount given in
the Bandwidth-Allocation TLV, the AN SHOULD NOT discontinue any
multicast streams in order to bring bandwidth down to within the new
limit, unless such action is required by local policy. However, the
AN MUST NOT admit new multicast streams that are subject to admission
control until it can do so within the limit specified by the
Bandwidth-Allocation TLV. As specified in Section 6.2.5.2, the AN
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MAY attempt to correct the situation by sending a request to the NAS
for an increased allocation of delegated bandwidth using the
Bandwidth Reallocation Request message.
Note: A race condition is possible where the AN sends a query, the
NAS requests more bandwidth, then receives and responds to the
query, and then receives the Bandwidth Transfer message responding
to its request. It is up to the AN to take appropriate action in
this case. The best action appears to be not to act on the result
of the first query but to repeat the query after sending the
Bandwidth Transfer message. Similar considerations apply to a
race between queries from both sides.
4.9. Multicast Flow Query Request and Response Messages
This section defines two new messages called the Multicast Flow Query
Request and Multicast Flow Query Response. The Multicast Flow Query
Request message is sent by the NAS to request information about the
multicast flows that are active on the AN. The Multicast Flow Query
Response message is sent in response by the AN to provide the
requested information to the NAS.
The Message Type for the Multicast Flow Query Request and Multicast
Flow Query Response messages is 149.
The contents of the Multicast Flow Query Request and Multicast Flow
Query Response messages depend on the nature of the query, as
described below.
4.9.1. Sender Behavior
The sender of a Multicast Flow Query Request message MUST set the
Result field to AckAll (0x2). The Result Code field MUST be set to
0x000. The sender MUST populate the ANCP Transaction Identifier
field with a unique value, as described in Section 3.6.1.6 of
[RFC6320].
The Multicast Flow Query Request message MAY be used by the NAS to
retrieve:
o the AN's view of which multicast flows are currently active on a
specified set of access ports; or
o the AN's view of the access ports on which a specified set of
multicast flows are currently active; or
o the AN's view of all the multicast flows currently active on each
access port of the AN.
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To retrieve the AN's view of which multicast flows are currently
active on a given port of the AN, the NAS MUST include a Target TLV
in the Multicast Flow Query Request payload identifying that port.
The Target TLV is encoded as specified in [RFC6320].
To retrieve the AN's view of the ports currently receiving a given
multicast flow, the NAS MUST include a Multicast-Flow TLV in the
Multicast Flow Query Request payload identifying that flow. The
Multicast-Flow TLV is encoded as specified in Section 5.12.
The NAS MAY include multiple Target TLVs or multiple Multicast-Flow
TLVs in the Multicast Flow Query Request message but MUST NOT include
both Target and Multicast-Flow TLVs in the same message.
To retrieve the AN's view of all of the multicast flows currently
active on each port of the AN, the NAS MUST send a Multicast Flow
Query Request message that does not contain any instance of the
Target TLV or the Multicast-Flow TLV.
4.9.2. Receiver Behavior
The AN MUST respond to a Multicast Flow Query Request message that
has a valid format and a valid content with a Multicast Flow Query
Response message. The Result field in the response MUST be set to
Success (0x3). The Result Code field MUST be set to 0. The
Transaction Identifier field MUST be copied from the request.
If the Multicast Flow Query Request contains one (or more) Target
TLVs, the AN MUST include, for each of these Target TLVs, the
following set of TLVs:
o Target TLV. This MUST be identical to the Target TLV in the
received Multicast Flow Query Request message.
o Multicast-Flow TLV(s). The Multicast-Flow TLV MUST appear once
per multicast flow that is currently active on the AN port
identified in the preceding Target TLV.
The Target TLVs MUST appear in the response from the AN in the same
order as in the query from the NAS.
If the Multicast Flow Query Request message contains one (or more)
Multicast-Flow TLVs, the AN MUST include, for each of these
Multicast-Flow TLVs, the following set of TLVs:
o Multicast-Flow TLV. This MUST be identical to the Multicast-Flow
TLV in the received Multicast Flow Query Request message.
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o Target TLV(s). The Target TLV MUST appear once per AN port on
which the multicast flow identified in the preceding Multicast-
Flow TLV is active.
The Multicast-Flow TLVs MUST appear in the response from the AN in
the same order as in the query from the NAS.
If the Multicast Flow Query Request message contains no Target TLV
and no Multicast Flow TLV, the AN MUST include, for each AN port
currently receiving multicast flow(s), the following set of TLVs:
o Target TLV. This MUST identify one AN port.
o Multicast-Flow TLV(s). The Multicast-Flow TLV MUST appear once
per Multicast Flow that is currently active on the AN port
identified in the preceding Target TLV.
If the contents of the Multicast Flow Query Request message are in
error, the AN MUST reply with a Multicast Flow Query Response message
with the Result field set to Failure (0x4) and the Result Code field
set to indicate the nature of the error. If the request contained
multiple instances of the Target TLV or the Multicast-Flow TLV and
one of these is in error, the response message MUST contain the
results for the preceding instances of the TLV as if there had been
no error. These successful results MUST be followed by the TLV in
error, copied from the request. The AN MUST NOT do further
processing of the request. The AN MAY add a Status-Info TLV to
provide further information on the nature of the error.
4.10. Committed Bandwidth Report Message
This section describes the Committed Bandwidth Report message, which
is sent from the AN to the NAS to report the most recent amount of
multicast bandwidth usage committed to one or more access lines.
The Message Type for the Committed Bandwidth Report message is 150.
The Committed Bandwidth Report message contains one or more instances
of the Committed-Bandwidth TLV, as described in Section 5.14.
4.10.1. Sender Behavior
The sender of a Committed Bandwidth Report message MUST set the
Result field to Ignore (0x0). The Result Code field MUST be set to
0x000. The sender MUST populate the ANCP Transaction Identifier
field with a unique value, as described in Section 3.6.1.6 of
[RFC6320].
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Each instance of the Committed-Bandwidth TLV included in the message
MUST identify an access line for which the amount of committed
multicast bandwidth has changed since the previous Committed
Bandwidth Report message was sent and MUST report the latest amount
of multicast bandwidth committed to that line. There MUST be only
one instance of the Committed-Bandwidth TLV present in the message
for any given access line. The message MUST include an instance of
the Committed-Bandwidth TLV for every access line for which committed
multicast bandwidth has changed since the previous Committed
Bandwidth Report message was sent.
Further behavior at the AN is specified in Section 6.2.2.
4.10.2. Receiver Behavior
The usage of the contents of a Committed Bandwidth Report message
received by the NAS is implementation-dependent. One example is that
the NAS uses the reports of multicast bandwidth commitments to adjust
its forwarding scheduler operation to provide the intended level of
QoS.
The NAS MUST NOT reply to a valid Committed Bandwidth Report message.
The NAS MAY send a Generic Response message indicating the nature of
any errors detected in a Committed Bandwidth Report message that it
has received.
5. ANCP TLVs For Multicast
This section defines new ANCP TLVs for the control of multicast
flows.
5.1. Multicast-Service-Profile TLV
This document defines the new Multicast-Service-Profile TLV.
The Multicast-Service-Profile TLV MAY be included in a Provisioning
message as specified in Section 4.1.
The Multicast-Service-Profile TLV is illustrated in Figure 7. It
consists of a TLV header encapsulating a single instance of the
Multicast-Service-Profile-Name TLV and one or more instances of the
List-Action TLV.
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1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mcast-Service-Profile 0x0013 | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast-Service-Profile-Name TLV |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| List-Action TLV |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ... |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| List-Action TLV |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: Multicast-Service-Profile TLV
The Multicast-Service-Profile TLV has the following fields:
o TLV Type: 0x0013
o TLV Length: determined by the contents following the TLV header.
o Multicast-Service-Profile-Name TLV: described in Section 5.2. The
Multicast-Service-Profile-Name TLV MUST contain an identifier that
is unique over all profiles provisioned to the same AN partition.
This identifier will be used to refer to the profile when
activating it for a given target within a Port Management message
(see Section 4.2).
o List-Action TLV: described in Section 5.3. The List-Action TLV(s)
provide the content of a newly defined multicast service profile
or modify the existing content. If more than one List-Action TLV
is present, the order of the TLVs may be significant, since List-
Action TLVs are processed in the order in which they appear.
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5.2. Multicast-Service-Profile-Name TLV
The Multicast-Service-Profile-Name TLV carries the identifier of a
multicast service profile provisioned on the AN. It is illustrated
in Figure 8.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mcast-Svc-Profile-Name 0x0018 | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast service profile identifier |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: Multicast-Service-Profile-Name TLV
The Multicast-Service-Profile-Name TLV has the following fields:
o TLV Type: 0x0018
o TLV Length: up to 255 octets.
o Multicast service profile identifier: an opaque sequence of octets
identifying a specific multicast service profile.
Note: The identifier could have the form of human-readable text
or an arbitrary binary value, depending on the operator's
practices.
5.3. List-Action TLV
The List-Action TLV identifies multicast flows to be added to or
removed from a list of white-, black-, or grey-listed flows. It is
meaningful only in association with a Multicast-Service-Profile-Name
TLV identifying the profile to which the List-Action TLV applies.
Such an association can be achieved by placing both TLVs in the same
base message payload or as embedded TLVs of another TLV such as the
Multicast-Service-Profile TLV. The List-Action TLV is shown in
Figure 9.
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1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = List-Action 0x0021 | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Operation | List Type | Reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Family | Number of flow fields |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast flow fields |
......
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Family | Number of flow fields |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast flow fields |
......
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: List-Action TLV
The List-Action TLV contains the following fields:
o TLV Type: 0x0021
o TLV Length: length of the subsequent contents.
o Operation: operation to be performed upon the white, black, or
grey list identified by the List Type field within the profile
identified by the associated Multicast-Service-Profile-Name
embedded TLV. The possible values are:
* 1 "Add": the multicast flow fields are to be added to the list.
* 2 "Delete": the multicast flow fields are to be removed from
the list. Each multicast flow field in the List-Action MUST
match exactly an existing entry in the list concerned. Thus,
to remove part of the range provided by a wildcarded list
entry, it is necessary to remove the entire entry and add back
the remaining partial range(s).
* 3 "Replace": the multicast flow fields replace the existing
contents of the list.
o List Type: the list type being modified by this List-Action TLV.
The possible values are 1 "White", 2 "Black", or 3 "Grey".
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o Reserved: a sender MUST set this field to zeroes. A receiver MUST
ignore the contents of this field.
o Address Family: the IP version of the set of multicast flow fields
that follow, encoded according to [PIMreg]. Possible values are 1
"IPv4" or 2 "IPv6". Either an IPv4 list or an IPv6 list or both
MAY be present in the List-Action TLV.
o Number of flow fields: the number of multicast flow fields of the
given address family that follows.
o Multicast flow field: a field identifying one or more multicast
flows. It consists of an 8-bit group address prefix length, an
8-bit source address prefix length, a group prefix of 0-16 octets,
and a source prefix of 0-16 octets, as shown in Figure 10.
Each multicast flow field refers either to a Source-Specific
Multicast (SSM) channel or to an Any-Source Multicast (ASM) group.
The scope of the designation may be broadened to multiple channels or
groups through use of prefix length values smaller than the total
address length for the given address family. Multicast flow fields
MUST be placed consecutively within the embedded TLV without
intervening padding except to round out individual addresses to the
nearest octet boundary.
A multicast flow field consists of two single-octet prefix lengths
followed by zero to two prefix values as shown in Figure 10:
+-+-+-+-+-+-+-+-+
| Group PrefLen |
+-+-+-+-+-+-+-+-+
| Source PrefLen|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group Prefix (multicast) (0 to 16 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source Prefix (unicast, SSM only) (0 to 16 octets) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: Organization of a Single Multicast Flow Field
The prefix length has its usual meaning. It is the number of most-
significant bits specified within the corresponding prefix. The
prefix length MAY vary from 0 to 32 in the IPv4 sub-list and from 0
to 128 in the IPv6 sub-list.
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A value of 0 for either the Group PrefLen (prefix length) or the
Source PrefLen indicates that any value of the corresponding address
will match (wildcard). If the value 0 is provided for a particular
prefix length, the corresponding prefix MUST be omitted from the
field contents.
The length of a Source or Group Prefix field is equal to (PrefLen +
7)/8 octets, truncated to the nearest integer. Unused bits at the
end of the prefix MUST be set to zeroes.
5.4. Sequence-Number TLV
The Sequence-Number TLV conveys a sequence number of some sort. The
specific meaning of the sequence number is message-specific. Within
this specification, the Sequence-Number TLV is used as an embedded
TLV in a Status-Info TLV in a Generic Response message reporting a
failed command in a Multicast Replication Control or Multicast
Admission Request message. It identifies the sequence number within
the message of the command that failed.
The Sequence-Number TLV has the format shown in Figure 11.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = Sequence-Number 0x0022 | TLV Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11: Sequence-Number TLV
The Sequence-Number TLV has the following fields:
o TLV Type: 0x0022
o TLV Length: 4
o Sequence number: the sequence number of a specific entity within a
series, where numbering starts from 1 for the first entity in the
series. Represented as a 32-bit binary number, most significant
bit first.
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5.5. Bandwidth-Allocation TLV
The Bandwidth-Allocation TLV is used to indicate the total amount of
video bandwidth delegated to the AN for multicast admission control
for a given access line, in kilobits per second. The TLV has the
format shown in Figure 12.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth-Allocation 0x0015 | TLV Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Delegated amount (kbits/s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12: Bandwidth-Allocation TLV
The Bandwidth-Allocation TLV has the following fields:
o TLV Type: 0x0015
o TLV Length: 4
o Delegated amount: the bandwidth amount delegated to the AN for
admission of multicast video on a given port, kilobits per second.
Represented as a 32-bit binary value, most significant bit first.
5.6. White-List-CAC TLV
The White-List-CAC TLV is used to indicate that the NAS wishes the AN
to do admission control for white-listed flows. Details on when the
White-List-CAC TLV may be provisioned are specified in Section 6.
The White-List-CAC TLV is illustrated in Figure 13.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = White-List-CAC 0x0024 | TLV Length = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13: White-List-CAC TLV
The White-List-CAC TLV contains the following fields:
o TLV Type: 0x0024
o TLV Length: 0, since the TLV contains no data other than the TLV
header.
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5.7. MRepCtl-CAC TLV
The MRepCtl-CAC TLV is used to indicate that the NAS wishes the AN to
do admission control for flows added by the Multicast Replication
Control message. Details on when the MRepCtl-CAC TLV may be
provisioned are specified in Section 6. The MRepCtl-CAC TLV is
illustrated in Figure 14.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|TLV Type = MRepCtl-CAC 0x0025 | TLV Length = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 14: MRepCtl-CAC TLV
The MRepCtl-CAC TLV contains the following fields:
o TLV Type: 0x0025
o TLV Length: 0, since the TLV contains no data other than the TLV
header.
5.8. Bandwidth-Request TLV
The Bandwidth-Request TLV is used to request an adjustment of the
total amount of video bandwidth allocated to the AN for multicast
admission control for a given line. The "Required amount" field
indicates the minimum adjustment required to meet the request. The
"Preferred amount" field indicates the adjustment the requestor would
prefer to have, if possible. Section 4.5 discusses the required
relationships between the "Required amount", "Preferred amount", and
current values of total bandwidth allocated to the AN.
The Bandwidth-Request TLV has the format shown in Figure 15.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type=Bandwidth-Request 0x0016 | TLV Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Required amount (kbits/s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Preferred amount (kbits/s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 15: Bandwidth-Request TLV
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The Bandwidth-Request TLV has the following fields:
o TLV Type: 0x0016
o TLV Length: 8 octets
o Required amount: the minimum or maximum amount, depending on
whether the sender is the AN or the NAS respectively, of delegated
video bandwidth that is being requested, in kilobits per second.
Represented as a 32-bit binary value, most significant bit first.
o Preferred amount: the preferred amount of delegated video
bandwidth that is being requested, in kilobits per second.
Represented as a 32-bit binary value, most significant bit first.
5.9. Request-Source-IP TLV
The Request-Source-IP TLV provides the IP address of the entity that
originated a specific request to join or leave a multicast channel.
The TLV is illustrated in Figure 16.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Request-Source-IP | TLV Length = 4 or 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unicast Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 16: Request-Source-IP TLV
The Request-Source-IP TLV contains the following fields:
o TLV Type: 0x0092
o TLV Length: 4 for an IPv4 address or 16 for an IPv6 address.
o Unicast address: IP address of the source of a multicast flow join
request, in network byte order.
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5.10. Request-Source-MAC TLV
The Request-Source-MAC TLV provides the MAC address of the entity
that originated a specific request to join or leave a multicast
channel. The TLV is illustrated in Figure 17.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|TLV Type=Request-Source-MAC | TLV Length = 6 or 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+-+-+- IEEE MAC Address +-+-+-+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 17: Request-Source-MAC TLV
The Request-Source-MAC TLV contains the following fields:
o TLV Type: 0x0093.
o TLV Length: either 6 octets (MAC-48 or EUI-48) or 8 octets (EUI-
64).
o IEEE MAC Address: MAC address of the device originating the
request to join a multicast flow. Within the address, bytes and
bits, respectively, shall be ordered from most to least
significant, consistent with [IEEE48] for MAC-48 and EUI-48 and
with [IEEE64] for EUI-64.
Note: EUI-48 and EUI-64 are registered trademarks of the IEEE.
5.11. Request-Source-Device-Id TLV
The Request-Source-Device-Id TLV provides a local identifier of the
entity that originated a specific request to join or leave a
multicast channel. The TLV is illustrated in Figure 18.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Request-Source-Device-Id | TLV Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identifier value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 18: Request-Source-Device-Id TLV
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The Request-Source-Device-Id TLV contains the following fields:
o TLV Type: 0x0096.
o TLV Length: 4
o Identifier value: local device identifier value, known to the AN
and AAA. Given that the scope of the identifier is a single
customer network, 32 bits is a more-than-sufficient numbering
space.
5.12. Multicast-Flow TLV
IGMPv3 [RFC3376] and MLDv2 [RFC3810] allow multicast listeners to
specify multiple source addresses for the same multicast group.
Similarly, the Multicast-Flow TLV specifies a multicast flow in terms
of its multicast group address and, if applicable, one or more
unicast source addresses. The Multicast-Flow TLV is illustrated in
Figure 19.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = Multicast-Flow 0x0019 | TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow Type | Addr Family | Number of Source Addresses |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast Group Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+--+
| Unicast Source Address (for SSM flows only) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 19: Multicast-Flow TLV
The Multicast-Flow TLV has the following fields:
o TLV Type: 0x0019
o TLV Length: ranges from a minimum of 8 (for an ASM IPv4 flow)
upwards. Total length is 4 + 4*(Number of Source Addresses +1)
for IPv4 or 4 + 16*(Number of Source Addresses + 1) for IPv6.
o Flow Type: 1 "Any-Source Multicast (ASM)", 2 "Source-Specific
Multicast (SSM)".
o Addr Family: address family of the multicast source and group
addresses, encoded in accordance with the IANA "PIM Address
Family" registry ([PIMreg]). 1 indicates IPv4; 2 indicates IPv6.
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o Number of Source Addresses: 0 for ASM, 1 or more for SSM.
o Multicast Group Address: a multicast group address within the
given address family. The group address MUST always be present.
o Unicast Source Address: unicast address within the given address
family. If the Flow Type is "ASM" (1), a source address MUST NOT
be present. If the Flow Type is "SSM" (2), the number of source
addresses given by the Number of Source Addresses field MUST be
present.
The full versions of IGMPv3 and MLDv2 support both INCLUDE and
EXCLUDE modes for specifying the desired sources for SSM flows. The
Multicast-Flow TLV supports INCLUDE mode only. [RFC5790]
(Lightweight IGMPv3 and MLDv2) provides guidance on converting
EXCLUDE mode IGMP/MLD records to INCLUDE mode for the Multicast-Flow
TLV.
5.13. Report-Buffering-Time TLV
The Report-Buffering-Time TLV provides the time for which a Committed
Bandwidth Report message must be held with the intention of
accumulating multiple reports of changed committed multicast
bandwidth in one report, to reduce the volume of messages sent to the
NAS. For further information see Section 6.2.2. The TLV is
illustrated in Figure 20.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Report-Buffering-Time 0x0094 | TLV Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Buffering Time (ms) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 20: Report-Buffering-Time TLV
The Report-Buffering-Time TLV contains the following fields:
o TLV Type: 0x0094
o TLV Length: 4 octets
o Buffering Time is a 32-bit unsigned integer containing a time
value in milliseconds (ms).
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5.14. Committed-Bandwidth TLV
The Committed-Bandwidth TLV identifies an access line and provides
the current amount of multicast bandwidth that the AN has committed
to it. The TLV is illustrated in Figure 21.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed-Bandwidth 0x0095 | TLV Length (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Committed Multicast Bandwidth (kbits/s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Target TLV ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 21: Committed-Bandwidth TLV
The Committed-Bandwidth TLV contains the following fields:
o TLV Type: 0x0095
o TLV Length: 4 octets plus the length of the Target TLV, including
its header and any padding.
o Committed Multicast Bandwidth: a 32-bit unsigned integer providing
a bandwidth amount in kbits/s.
o Target TLV: identifies the access line to which this amount of
multicast bandwidth is currently committed.
6. Multicast Capabilities
Section 3.5 of [RFC6320] defines a capability negotiation mechanism
as well as a number of capabilities. This section defines five new
capabilities in support of different modes of multicast operation:
o NAS-initiated multicast replication (capability type 3);
o committed bandwidth reporting (capability type 5);
o conditional access and admission control with white and black
lists (capability type 6);
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RFC 7256 ANCP Multicast Extensions July 2014
o conditional access and admission control with grey lists
(capability type 7); and
o bandwidth delegation (capability type 8).
The "Capability Data" field within the Capability TLV for all of
these capabilities is empty. All of these capabilities are
independent of the access technology.
The remainder of this section consists of three sub-sections.
Section 6.1 specifies the protocol elements that must be implemented
in order to support each capability. Section 6.2 specifies the
procedures that apply to each capability on its own. Section 6.3
specifies how the capabilities interact if more than one multicast
capability is included in the set of capabilities negotiated between
the AN and the NAS.
6.1. Required Protocol Support
This section specifies the protocol elements that MUST be implemented
to support each of the five multicast capabilities. Support of
multiple multicast capabilities requires implementation of the union
of the sets of protocol elements applying to each of the individual
capabilities in the supported set.
In addition to the elements listed below, implementation of the
Target TLV (Section 4.3 of [RFC6320]) is REQUIRED for all of the
capabilities specified in this document.
6.1.1. Protocol Requirements for NAS-Initiated Multicast Replication
Table 1 specifies the protocol elements within Section 4 and
Section 5 that MUST be implemented to support the NAS-initiated
multicast replication capability. Additionally, implementation of
the Multicast Replication Control message requires implementation of
the Command TLV (Section 4.4 of [RFC6320] with additional details in
Section 4.3 of this document).
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RFC 7256 ANCP Multicast Extensions July 2014
+--------------+----------------------------------------------------+
| Reference | Protocol Element |
+--------------+----------------------------------------------------+
| Section 4.1 | Provisioning message with MRepCtl-CAC TLV |
| | |
| Section 4.2 | Port Management message with Bandwidth-Allocation |
| | TLV |
| | |
| Section 4.3 | Multicast Replication Control message |
| | |
| Section 4.9 | Multicast Flow Query Request and Response messages |
| | |
| Section 5.4 | Sequence Number TLV |
| | |
| Section 5.5 | Bandwidth-Allocation TLV |
| | |
| Section 5.7 | MRepCtl-CAC TLV |
| | |
| Section 5.12 | Multicast-Flow TLV |
+--------------+----------------------------------------------------+
Table 1: Protocol Requirements for NAS-Initiated Multicast
Replication
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6.1.2. Protocol Requirements for Committed Multicast Bandwidth
Reporting
Table 2 specifies the protocol elements within Section 4 and
Section 5 that MUST be implemented to support the committed multicast
bandwidth reporting capability.
+--------------+----------------------------------------------------+
| Reference | Protocol Element |
+--------------+----------------------------------------------------+
| Section 4.1 | Provisioning message with Report-Buffering-Time |
| | TLV |
| | |
| Section 4.10 | Committed Bandwidth Report message |
| | |
| Section 4.9 | Multicast Flow Query Request and Response messages |
| | |
| Section 5.13 | Report-Buffering-Timer TLV |
| | |
| Section 5.14 | Committed-Bandwidth TLV |
| | |
| Section 5.12 | Multicast-Flow TLV |
+--------------+----------------------------------------------------+
Table 2: Protocol Requirements for Committed Multicast Bandwidth
Reporting
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6.1.3. Protocol Requirements for Conditional Access and Admission
Control with White and Black Lists
Table 3 specifies the protocol elements within Section 4 and
Section 5 that MUST be implemented to support the conditional access
and admission control with white and black lists multicast
capability.
+--------------+----------------------------------------------------+
| Reference | Protocol Element |
+--------------+----------------------------------------------------+
| Section 4.1 | Provisioning message with Multicast-Service- |
| | Profile TLV, white and black lists only, and |
| | White-List-CAC TLV |
| | |
| Section 4.2 | Port Management message with Multicast-Service- |
| | Profile-Name and Bandwidth-Allocation TLVs |
| | |
| Section 4.9 | Multicast Flow Query Request and Response messages |
| | |
| Section 5.1 | Multicast-Service-Profile TLV |
| | |
| Section 5.2 | Multicast-Service-Profile-Name TLV |
| | |
| Section 5.3 | List-Action TLV, white and black lists only |
| | |
| Section 5.5 | Bandwidth-Allocation TLV |
| | |
| Section 5.6 | White-List-CAC TLV |
| | |
| Section 5.12 | Multicast-Flow TLV |
+--------------+----------------------------------------------------+
Table 3: Protocol Requirements for Conditional Access and Admission
Control with White and Black Lists
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6.1.4. Protocol Requirements for Conditional Access and Admission
Control with Grey Lists
Table 4 specifies the protocol elements within Section 4 and
Section 5 that MUST be implemented to support the conditional access
and admission control with grey lists multicast capability.
Additionally, implementation of the Multicast Replication Control
message requires implementation of the Command TLV (Section 4.4 of
[RFC6320] with additional details in Section 4.3 of this document).
+--------------+----------------------------------------------------+
| Reference | Protocol Element |
+--------------+----------------------------------------------------+
| Section 4.1 | Provisioning message with Multicast-Service- |
| | Profile TLV, grey lists only, and MRepCtl-CAC TLV |
| | |
| Section 4.2 | Port Management message with Multicast-Service- |
| | Profile-Name and Bandwidth-Allocation TLVs |
| | |
| Section 4.3 | Multicast Replication Control message |
| | |
| Section 4.4 | Multicast Admission Control message |
| | |
| Section 4.9 | Multicast Flow Query Request and Response messages |
| | |
| Section 5.1 | Multicast-Service-Profile TLV, grey lists only |
| | |
| Section 5.2 | Multicast-Service-Profile-Name TLV |
| | |
| Section 5.3 | List-Action TLV, grey lists only |
| | |
| Section 5.4 | Sequence Number TLV |
| | |
| Section 5.5 | Bandwidth-Allocation TLV |
| | |
| Section 5.7 | MRepCtl-CAC TLV |
| | |
| Section 5.9 | Request-Source-IP TLV |
| | |
| Section 5.10 | Request-Source-MAC TLV |
| | |
| Section 5.11 | Request-Source-Device-Id TLV |
| | |
| Section 5.12 | Multicast-Flow TLV |
+--------------+----------------------------------------------------+
Table 4: Protocol Requirements for Conditional Access and Admission
Control with Grey Lists
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6.1.5. Protocol Requirements for Bandwidth Delegation
Table 5 specifies the protocol elements within Section 4 and
Section 5 that MUST be implemented to support the bandwidth
delegation capability.
+--------------+----------------------------------------------------+
| Reference | Protocol Element |
+--------------+----------------------------------------------------+
| Section 4.2 | Port Management message with Bandwidth-Allocation |
| | TLV |
| | |
| Section 4.5 | Bandwidth Reallocation Request message |
| | |
| Section 4.6 | Bandwidth Transfer message |
| | |
| Section 4.7 | Delegated Bandwidth Query Request message |
| | |
| Section 4.8 | Delegated Bandwidth Query Response message |
| | |
| Section 4.9 | Multicast Flow Query Request and Response messages |
| | |
| Section 5.5 | Bandwidth-Allocation TLV |
| | |
| Section 5.8 | Bandwidth-Request TLV |
| | |
| Section 5.12 | Multicast-Flow TLV |
+--------------+----------------------------------------------------+
Table 5: Protocol Requirements for Bandwidth Delegation
6.2. Capability-Specific Procedures for Providing Multicast Service
This section describes multicast service procedures for each
capability as if it were the only multicast capability within the
negotiated set. Procedures involving combinations of multicast
capabilities are described in Section 6.3.
The use of the Multicast Flow Query Request and Response messages to
determine the association between multicast flows and ports is common
to all multicast capabilities. No additional text is required here,
beyond that already given in Section 4.9 to describe the use of those
messages.
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6.2.1. Procedures for NAS-Initiated Multicast Replication
NAS-initiated multicast replication may be negotiated to support a
mode of operation where IGMP/MLD requests are terminated on the NAS.
Alternatively, it may be negotiated to allow the NAS to respond to
requests sent by other means (e.g., through application signaling)
that require the replication of multicast channels to a given access
line.
6.2.1.1. Provisioning
The NAS MAY perform admission control for NAS-initiated replication.
In this case, it MUST NOT include the MRepCtl-CAC TLV in a
Provisioning message sent to the AN. Alternatively, the NAS MAY
enable admission control at the AN for NAS-initiated multicast
replication. To do this, it MUST include the MRepCtl-CAC TLV in a
Provisioning message sent to the AN, and it MUST also include a
Bandwidth-Allocation TLV in a Port Management message for each access
line.
6.2.1.2. Multicast Service Procedures
The procedures associated with NAS-initiated multicast replication
are straightforward. To initiate replication, the NAS MUST send a
Multicast Replication Control message to the AN, containing one or
more commands adding flows, as described in Section 4.3.1. To
terminate replication, the NAS MUST send a Multicast Replication
Control message where the commands delete instead of adding the
flows. The AN acts upon these messages as specified in
Section 4.3.2.
6.2.2. Procedures for Committed Bandwidth Reporting
Committed bandwidth reporting may be negotiated if the NAS requires
current knowledge of the amount of multicast bandwidth committed to
each access line and cannot obtain this information by other means.
6.2.2.1. Provisioning
The default buffering time when committed bandwidth reporting is
enabled is zero (immediate reporting). To change this, the NAS MAY
send an instance of the Report-Buffering-Time TLV containing a non-
zero time value to the AN in a Provisioning message. If the NAS
subsequently wishes to change the buffering time again, it MAY do so
in another Provisioning message.
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6.2.2.2. Multicast Service Procedures
If the buffering time for committed bandwidth reporting is zero, the
AN MUST send a Committed Bandwidth Report message to the NAS each
time the amount of multicast bandwidth committed to any access line
under its control changes.
If a non-zero value is provided in the Report-Buffering-Time TLV, the
AN is in one of two states at any given moment: not-buffering or
buffering. The AN enters buffering state if it is in not-buffering
state and the multicast bandwidth amount committed to some access
line changes. It leaves buffering state when the AN sends a
Committed Bandwidth Report message.
Upon entry to the buffering state, the AN MUST start a buffering
timer and create a Committed Bandwidth Report message containing a
Committed-Bandwidth TLV for the triggering access line, but it MUST
NOT send it. If a multicast bandwidth change occurs for another
access line, the AN MUST add a new Committed-Bandwidth TLV to the
message for that additional line. If a multicast bandwidth change
occurs for a line for which a Committed-Bandwidth TLV is already
present in the buffered report, the AN MUST update the corresponding
Committed-Bandwidth TLV to contain the new bandwidth value rather
than adding another Committed-Bandwidth TLV for the same access line.
The buffering timer expires after the period provided by the Report-
Buffering-Time TLV. When it expires, the AN MUST send the Committed
Bandwidth Report message that it has been accumulating to the NAS.
Exceptionally, the AN MAY choose to send the message before the timer
expires, in which case it MUST clear the buffering timer when the
message is sent. In either case, the AN enters the not-buffering
state as a result.
Note: Report buffering implies that NAS reaction to changes in
multicast bandwidth usage is delayed by the amount of the
buffering period. The choice of buffering period must take this
into consideration.
6.2.3. Procedures for Conditional Access and Admission Control with
Black and White Lists
6.2.3.1. Provisioning
The NAS provisions named multicast service profiles containing white
and black lists on the AN using the Provisioning message containing
one or more Multicast-Service-Profile TLVs. The NAS MAY update the
contents of these profiles from time to time as required by sending
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RFC 7256 ANCP Multicast Extensions July 2014
additional Provisioning messages with Multicast-Service-Profile TLVs
containing incremental modifications to the existing white and black
lists or replacements for them.
The NAS assigns a specific multicast service profile to an individual
access line using the Port Management message containing a Multicast-
Service-Profile-Name TLV. The NAS MAY change the multicast service
profile for a given access line at any time by sending a Port
Management message identifying a new multicast service profile.
The NAS MAY choose to enable admission control at the AN for white-
listed flows. To do this, it MUST send a Provisioning message as
described in Section 4.1, which includes the White-List-CAC TLV, and
it MUST provide a multicast bandwidth allocation for each access line
by including a Bandwidth-Allocation TLV in a Port Management message.
6.2.3.2. Multicast Service Procedures
The conditional access and admission control with white and black
lists capability assumes that IGMP/MLD requests are terminated on the
AN. When the AN receives a join request, it MUST check to see
whether the requested flow is white-listed or black-listed as
described below. Requests for black-listed flows MUST be discarded.
If the NAS has enabled admission control on the AN as described in
the previous section, but a white-listed flow would cause the amount
of committed multicast bandwidth to exceed the provisioned limit, the
request MUST be discarded. The AN replicates flows passing these
checks to the access line.
To determine if a requested flow is white-listed, the AN searches for
a best match to the flow in the applicable multicast service profile.
Matching is done on the prefixes specified in the profile, ignoring
the address bits of lower order than those in the prefix.
If the requested multicast flow matches multiple lists associated
with the access line, then the most specific match will be considered
by the AN. If the most specific match occurs in multiple lists, the
black list entry takes precedence over the white list. In this
context, the most specific match is defined as:
o first, most specific match (longest prefix length) on the
multicast group address (i.e., on G of <S,G>), and
o then, most specific match (longest prefix length) on the unicast
source address (i.e., on S of <S,G>).
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If the requested multicast flow is not part of any list, the join
message SHOULD be discarded by the AN. This default behavior can
easily be changed by means of a "catch-all" statement in the white
list. For instance, adding (<S=*,G=*>) in the white List would make
the default behavior to accept join messages for a multicast flow
that has no other match on any list.
When the AN receives a leave request, it terminates replication of
the multicast flow.
If the AN receives a Provisioning message that updates an existing
multicast service profile, the AN MUST review the status of active
flows on all ports to which the updated profile is currently
assigned. Similarly, if a Port Management message assigns a new
multicast service profile to a given port, the AN MUST review all
active flows on that port. If the most specific match for any flow
is a black list entry, the flow MUST be terminated immediately. If
any of the remaining flows do not match an entry in the white list,
they also MUST be terminated immediately. White-listed flows MUST be
allowed to continue.
6.2.4. Procedures for Conditional Access and Admission Control with
Grey Lists
6.2.4.1. Provisioning
The NAS provisions named multicast service profiles containing grey
lists on the AN using the Provisioning message containing one or more
Multicast-Service-Profile TLVs. The NAS MAY update the contents of
these profiles from time to time as required by sending additional
Provisioning messages with Multicast-Service-Profile TLVs containing
incremental modifications to the existing grey lists or replacements
for them.
The NAS assigns a specific multicast service profile to an individual
access line using the Port Management message containing a Multicast-
Service-Profile-Name TLV. The NAS MAY change profiles on the line by
sending a subsequent Port Management message identifying a new
profile.
The NAS MAY perform admission control for grey-listed flows. In that
case, the NAS MUST NOT include the MRepCtl-CAC TLV in a Provisioning
message sent to the AN. Alternatively, the NAS MAY enable admission
control at the AN for grey-listed flows. To do this, it MUST include
the MRepCtl-CAC TLV in a Provisioning message sent to the AN and MUST
also provide a Bandwidth-Allocation TLV in a Port Management message
for each access line.
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6.2.4.2. Multicast Service Procedures
The conditional access and admission control with grey lists
capability assumes that IGMP/MLD requests are terminated on the AN.
When the AN receives a join request, it MUST determine whether there
is a match to the requested flow in the grey list of the multicast
service profile provisioned against the given access line. If there
is no match, the request is discarded. Otherwise, the AN MUST send a
Multicast Admission Control message to the NAS with content
identifying the access line and the multicast flow to be added. As
indicated in Section 4.4, the AN MAY add information identifying the
requesting device.
If the NAS decides to enable the flow, it MUST send a Multicast
Replication Control message to the AN to replicate the flow to the
access line with the Result field set to Nack (0x1), as described in
Section 4.3.1.
When the AN receives the Multicast Replication Control message, it
performs admission control if that has been enabled as described in
the previous section. If admitting the flow would cause the
committed multicast bandwidth at the access line to exceed the
provisioned limit, the AN reports an error to the NAS as described in
Section 4.3.2. Otherwise, it replicates the multicast flow as
requested.
If the NAS decides not to permit the flow, it MAY send a Multicast
Replication Control message in response to the Multicast Admission
Control message to allow the AN to update its internal records. The
content of this message is described in Section 4.4.2.
When the AN receives a leave request, it MUST terminate replication
of the flow to the access line. It MUST then send a Multicast
Admission Control message to the NAS indicating the deletion. The
NAS updates its internal records but MUST NOT respond to the message.
If the AN receives a Provisioning message that updates an existing
multicast service profile, the AN MUST review the status of active
flows on all ports to which the updated profile has been assigned.
Similarly, if the AN receives a Port Management message that assigns
a new profile to a given port, the AN MUST review all active flows on
that port. In either case, if any flow does not match an entry in
the grey list, it MUST be terminated immediately.
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6.2.5. Procedures for Bandwidth Delegation
6.2.5.1. Provisioning
The NAS SHOULD provision an initial amount of delegated multicast
bandwidth for each access line using the Port Management message
containing the Bandwidth-Allocation TLV.
Note: If it fails to do so and a value has not been provisioned on
the AN by other means, the AN will be forced to request a
bandwidth allocation as soon as it receives a join request.
The NAS MAY, at any time, force an update of the amount of delegated
bandwidth by the same means.
6.2.5.2. Multicast Service Procedures
The bandwidth delegation capability assumes that IGMP/MLD requests
are terminated on the AN. When the AN receives a join request, it
checks whether it has sufficient remaining uncommitted multicast
bandwidth on the access line to accommodate the new multicast flow.
If not, it MAY send a request to the NAS for an increased allocation
of delegated bandwidth using the Bandwidth Reallocation Request
message. The NAS MUST return a Bandwidth Transfer message indicating
whether it has granted the request and, if so, the new amount of
delegated bandwidth.
If the AN has sufficient uncommitted multicast capacity to admit the
request, either originally or as the result of a successful request
to the NAS, it replicates the requested flow to the access line.
Otherwise, it discards the request.
When the AN receives a leave request for an active flow, it ceases
replication.
The NAS or AN MAY, at some point, detect that their respective views
of the amount of delegated bandwidth are inconsistent. If so, they
can recover using procedures described in Sections 4.5 and 4.6. As a
further aid to synchronization, either the NAS or the AN MAY from
time to time check the peer's view of the amount of delegated
bandwidth using the Delegated Bandwidth Query message.
The NAS or AN MAY, at any time, release bandwidth to the peer using
an autonomous Bandwidth Transfer message. The contents of this
message are described in Section 4.6.
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6.3. Combinations of Multicast Capabilities
6.3.1. Combination of Conditional Access and Admission Control with
White and Black Lists and Conditional Access and Admission
Control with Grey Lists
If conditional access and admission control with white and black
lists is combined with conditional access and admission control with
grey lists, provisioning of the multicast service profiles is as
described in Section 6.2.3.1 except that multicast service profiles
will also include grey lists. Admission control is enabled
independently on the AN for white lists by including the White-List-
CAC TLV in the Provisioning message and for grey lists by including
the MRepCtl-CAC TLV in the Provisioning message. The Bandwidth-
Allocation TLV provisions an amount that applies to both white- and
grey-listed flows if admission control is enabled for both.
With regard to multicast service procedures, one point of difference
from the individual capabilities must be noted. This is an
interaction during the profile matching procedure. The AN MUST seek
the best match among multiple lists as described in Section 6.2.3.2.
However, if there are multiple matches of equal precision, the order
of priority is black list first, grey list second, and white list
last.
Once profile matching has been completed, processing of a join
request is as described in Section 6.2.3.2 for white- or black-listed
flows or Section 6.2.4.2 for grey-listed flows. Requests that do not
match any list SHOULD be discarded.
When the AN receives a leave request, it MUST terminate replication
of the flow to the access line. If the flow was grey-listed, the AN
MUST then send a Multicast Admission Control message to the NAS
indicating the deletion.
If the AN receives a Provisioning message that updates an existing
multicast service profile, the AN MUST review the status of active
flows on all ports to which the updated profile is currently
assigned. Similarly, if a Port Management message assigns a new
multicast service profile to a given port, the AN MUST review all
active flows on that port. If any flow has its most specific match
in a black list entry, it MUST be terminated immediately. If any of
the remaining flows do not match an entry in the white or grey list,
they MUST also be terminated immediately. Finally, if any remaining
flows were originally admitted because they were white-listed but
after the change they are grey-listed, the AN MUST generate a
Multicast Flow Query Response message autonomously as if it were
responding to a Multicast Flow Query Request message, listing all
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such flows. These flows MUST be allowed to continue until the NAS or
the subscriber terminates them. Flows with their most specific match
in the white list MUST be allowed to continue.
The autonomously generated Multicast Flow Query Response message MUST
be formatted as if it were a successful response to a request
containing no Target and no Multicast-Flow TLV, as described in
Section 4.9.2, with the exception that the Transaction Identifier
field MUST be set to all zeroes.
Note: The procedures in the previous paragraphs imply that the AN
has to retain a memory of whether an admitted flow was white-
listed or grey-listed at the time of its admission/readmission.
6.3.2. Combination of Conditional Access and Admission Control with
Bandwidth Delegation
The provisioning and bandwidth management procedures of Section 6.2.5
apply in addition to the procedures in Sections 6.2.3, 6.2.4, or
6.3.1 as applicable. Conditional access follows the rules given in
those sections in terms of matching flows against white and black
and/or grey lists. When admission control is enabled at the AN, the
amount of bandwidth used by the AN is negotiable as described in
Section 6.2.5.2.
6.3.3. Combination of NAS-Initiated Replication with Other Capabilities
NAS-initiated multicast replication can coexist with the other
capabilities, but some means must exist to prevent double replication
of flows. The simplest way to do this is to terminate all IGMP/MLD
requests on the AN, so that NAS-initiated multicast replication is
stimulated only by signaling through other channels. Other
arrangements are possible but need not be discussed here.
Assuming the necessary separation of responsibilities, the only point
of interaction between NAS-initiated multicast replication and the
other multicast capabilities is in the area of admission control.
Specifically, if the AN is to do admission control for flows added by
Multicast Replication Control messages, regardless of whether they
are part of NAS-initiated replication or grey list multicast service
processing, the NAS includes the MRepCtl-CAC TLV in a Provisioning
message and the Bandwidth-Allocation TLV in a Port Management
message. If, instead, the NAS will do admission control for flows
added by Multicast Replication Control messages, regardless of
whether they are part of NAS-initiated replication or grey list
multicast service processing, it does not send the MRepCtl-CAC TLV in
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a Provisioning message to the AN. The NAS can independently enable
admission control for white flows on the AN by including the White-
List-CAC TLV in the Provisioning message.
6.3.4. Combinations of Committed Bandwidth Reporting with Other
Multicast Capabilities
Committed bandwidth reporting can take place independently of other
multicast capabilities that have been negotiated. However, some
combinations do not make sense because of redundancy. In particular,
the NAS obtains the same information that committed bandwidth
reporting gives if the only other capabilities operating are NAS-
initiated replication and/or conditional access and admission control
with grey lists.
7. Miscellaneous Considerations
This section deals with two sets of considerations. "Report
Buffering Considerations" considers requirements for configuration in
support of some of the committed bandwidth reporting capability.
"Congestion Considerations" is a warning to implementors about the
possibility of control-plane congestion, with suggestions for
mitigation.
7.1. Report Buffering Considerations
The committed bandwidth reporting capability allows the provisioning
of a report buffering period to reduce the number of messages the AN
passes to the NAS. An appropriate value for this period, if
buffering is allowed at all, depends first on the effect of delay in
reporting bandwidth changes and secondly on the rate at which
bandwidth changes are expected to occur.
Let us assume, in the first instance, that a delay in adjusting
hierarchical scheduling at the NAS causes additional bandwidth demand
to be served momentarily on a best-effort basis, introducing the
possibility of jitter and, more crucially, packet loss. Appendix IV
of ITU-T Recommendation G.1080 [ITU-T_G.1080] indicates that the
maximum tolerable duration of a loss episode is less than 16 ms.
This would more likely apply in the middle of a program rather than
when it was starting up but at least gives an (extremely
conservative) order of magnitude for setting the buffering period.
The next question is whether enough messaging is likely to be
generated that multiple bandwidth changes would be observed within
such an interval. Let us consider a reasonable example in a DSL
environment, where during the busiest hour of the day subscribers
start watching at the rate of one program per subscriber per hour.
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Typically, because of program scheduling, the new channel requests
might be concentrated within a three-minute period, giving an
effective request rate of 1/(3 minutes * 60 seconds * 1000 ms/second)
* 16 ms = 0.00009 requests per buffering interval of 16 ms. With
these figures, an AN serving 10,000 subscribers will report an
average of 0.9 bandwidth changes per 16 ms buffering interval. It
appears that buffering is worthwhile only for larger-scale
deployments.
Note that simple replacement of one channel with another -- channel
surfing -- does not require reporting or adjustment at the NAS end.
7.2. Congestion Considerations
Implementors must beware of the possibility that a single channel-
surfing subscriber could generate enough control messaging to
overload the AN or the messaging channel between the AN and the NAS.
The implementation problem is to strike the right balance between
minimizing the processing of requests that have been overtaken by
subsequent events and meeting requirements for what is termed
"channel zapping delay". Nominally, such a requirement is to be
found in Section 8.1 of [ITU-T_G.1080], but unfortunately no
quantitative value was available at the time of publication of this
document. Implementors will therefore have to base their work on
discussions with customers until standardized requirements become
available. (It is possible that regional bodies or more specialized
bodies have overtaken the ITU-T in this regard.)
A typical strategy for minimizing the work associated with request
processing includes deliberate buffering of join requests for a short
period in case matching Release requests are detected, followed by
discard of both requests. More generally, processing of requests
from individual subscribers may be rate limited, and the global rate
of messaging to the NAS can also be limited. If the AN gets
overloaded, deliberate dropping of stale requests can be implemented,
for some definitions of "stale".
8. Security Considerations
The security considerations of ANCP are discussed in [RFC6320] and in
[RFC5713]. Multicast does not, in principle, introduce any new
security considerations, although it does increase the attractiveness
of ANCP as a means of denial of service (e.g., through direction of
multicast streams onto the target) or theft of service.
As mentioned in Section 4.4, the inclusion of the Request-Source-MAC
TLV or Request-Source-IP TLV in the Multicast Admission Control
message presents privacy issues. An attacker able to get access to
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the contents of this message would, like the content provider, be
able to track consumption of multicast content to the individual
device and potentially to individual persons if they are associated
with particular devices. To make the connection between devices and
individuals, the attacker needs to get information from sources other
than ANCP, of course, but let us assume that this has happened.
The protection specified for ANCP in [RFC6320] will apply to the
transmission of the Multicast Admission Control message across the
access network to the NAS. Hence, the attacker's potential points of
access are between the subscriber and the AN, at the AN and at the
NAS. Moreover, if the MAC or IP address are transmitted onwards from
the NAS to AAA in a request for policy, that whole onward path has to
be examined for vulnerability.
The question is how many of these potential points of attack can be
eliminated through operational practice. The segment from the
subscriber through the AN itself seems out of the scope of this
discussion -- protection of this segment is basic to subscriber
privacy in any event and likely a business requirement. The segment
from the AN to the NAS is covered by the basic ANCP protection
specified in [RFC6320]. This leaves the NAS and the path between the
NAS and AAA for consideration.
The operator can eliminate the path between the NAS and AAA as a
point where the attacker can access per-device information by
downloading per-device policy to the NAS for all identified user
devices for the particular subscriber. The NAS then selects the
applicable policy based on the particular device identifier it has
received. This is as opposed to the NAS sending the identifier of
the device in question to AAA and getting policy just for that
device.
The alternative is to protect the path between the NAS and AAA. If
Diameter is used as the AAA protocol, Section 2.2 of [RFC6733]
mandates use of IPsec, TLS/TCP, or DTLS/SCTP for that purpose. If
RADIUS is used, the operator should deploy TLS transport as specified
in [RFC6614].
This leaves the NAS itself as a point of attack. In theory, the NAS
could be eliminated if the AN remapped the requesting MAC or IP
address to an identifier known to itself and AAA but not the NAS.
This would require local configuration on the AN, which may be
possible under some circumstances. The Request-Source-Device-Id TLV
specified in Section 5.11 is available to transmit such an identifier
in place of the Request-Source-MAC TLV or Request-Source-IP TLV.
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9. IANA Considerations
This document defines the following additional values within the
"ANCP Message Types" registry:
+--------------+--------------------------------+-----------+
| Message Type | Message Name | Reference |
+--------------+--------------------------------+-----------+
| 144 | Multicast Replication Control | RFC 7256 |
| | | |
| 145 | Multicast Admission Control | RFC 7256 |
| | | |
| 146 | Bandwidth Reallocation Request | RFC 7256 |
| | | |
| 147 | Bandwidth Transfer | RFC 7256 |
| | | |
| 148 | Delegated Bandwidth Query | RFC 7256 |
| | | |
| 149 | Multicast Flow Query | RFC 7256 |
| | | |
| 150 | Committed Bandwidth Report | RFC 7256 |
+--------------+--------------------------------+-----------+
This document defines the following additional values for the "ANCP
Result Codes" registry. In support of these assignments, IANA has
changed the lower limit of 0x100 specified by [RFC6320] for
assignments by IETF Consensus to 0x64.
+------------+------------------------------------------+-----------+
| Result | One-Line Description | Reference |
| Code | | |
+------------+------------------------------------------+-----------+
| 0x64 | Command error. | RFC 7256 |
| | | |
| 0x65 | Invalid flow address. | RFC 7256 |
| | | |
| 0x66 | Multicast flow does not exist. | RFC 7256 |
| | | |
| 0x67 | Invalid preferred bandwidth amount. | RFC 7256 |
| | | |
| 0x68 | Inconsistent views of delegated | RFC 7256 |
| | bandwidth amount. | |
| | | |
| 0x69 | Bandwidth request conflict. | RFC 7256 |
+------------+------------------------------------------+-----------+
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This document defines the following additional values for the "ANCP
Command Codes" registry:
+----------------+--------------------------------------+-----------+
| Command Code | Command Code Directive Name | Reference |
| Value | | |
+----------------+--------------------------------------+-----------+
| 1 | Add | RFC 7256 |
| | | |
| 2 | Delete | RFC 7256 |
| | | |
| 3 | Delete All | RFC 7256 |
| | | |
| 4 | Admission Control Reject | RFC 7256 |
| | | |
| 5 | Conditional Access Reject | RFC 7256 |
| | | |
| 6 | Admission Control and Conditional | RFC 7256 |
| | Access Reject | |
+----------------+--------------------------------------+-----------+
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This document defines the following additional values within the
"ANCP TLV Types" registry:
+-----------+--------------------------------+-----------+
| Type Code | TLV Name | Reference |
+-----------+--------------------------------+-----------+
| 0x0013 | Multicast-Service-Profile | RFC 7256 |
| | | |
| 0x0015 | Bandwidth-Allocation | RFC 7256 |
| | | |
| 0x0016 | Bandwidth-Request | RFC 7256 |
| | | |
| 0x0018 | Multicast-Service-Profile-Name | RFC 7256 |
| | | |
| 0x0019 | Multicast-Flow | RFC 7256 |
| | | |
| 0x0021 | List-Action | RFC 7256 |
| | | |
| 0x0022 | Sequence-Number | RFC 7256 |
| | | |
| 0x0024 | White-List-CAC | RFC 7256 |
| | | |
| 0x0025 | MRepCtl-CAC | RFC 7256 |
| | | |
| 0x0092 | Request-Source-IP | RFC 7256 |
| | | |
| 0x0093 | Request-Source-MAC | RFC 7256 |
| | | |
| 0x0094 | Report-Buffering-Time | RFC 7256 |
| | | |
| 0x0095 | Committed-Bandwidth | RFC 7256 |
| | | |
| 0x0096 | Request-Source-Device-Id | RFC 7256 |
+-----------+--------------------------------+-----------+
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This document defines the following additional values for the "ANCP
Capability Types" registry:
+-------+-------------------------+--------+------------+-----------+
| Value | Capability Type Name | Tech | Capability | Reference |
| | | Type | Data? | |
+-------+-------------------------+--------+------------+-----------+
| 3 | NAS-Initiated Multicast | 0 | No | RFC 7256 |
| | Replication | | | |
| | | | | |
| 5 | Committed Bandwidth | 0 | No | RFC 7256 |
| | Reporting | | | |
| | | | | |
| 6 | Conditional Access and | 0 | No | RFC 7256 |
| | Admission Control with | | | |
| | White and Black Lists | | | |
| | | | | |
| 7 | Conditional Access and | 0 | No | RFC 7256 |
| | Admission Control with | | | |
| | Grey Lists | | | |
| | | | | |
| 8 | Bandwidth Delegation | 0 | No | RFC 7256 |
+-------+-------------------------+--------+------------+-----------+
10. Acknowledgements
The authors would like to acknowledge Wojciech Dec for providing
useful input to this document, Robert Rennison for his help in
shaping the definition of the Multicast-Service-Profile TLV, Shridhar
Rao for his comments and suggestions, and Aniruddha A for his
proposal that formed the base of the Multicast Flow Reporting
solution. Philippe Champagne, Sanjay Wadhwa, and Stefaan De Cnodder
provided substantial contributions on the solution for the NAS-
initiated multicast control use case. Kristian Poscic provided the
committed bandwidth reporting use case.
Thanks to the Document Shepherd, Matthew Bocci, and Area Director,
Ted Lemon, for points raised by their reviews following Working Group
Last Call.
Further thanks to Dacheng Zhang, Mehmet Ersue, and Christer Holmberg
for their reviews on behalf of the Security, Operations, and Gen-Art
directorates. Dacheng's comments led to changes at several points in
the document, while Mehmet's led to creation of the Miscellaneous
Considerations section. Finally, thanks to Brian Haberman for
stimulating a review of the architectural assumptions and their
relationship to the ability of user devices to obtain access to non-
IPTV multicast services. This also led to changes in the document.
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11. References
11.1. Normative References
[PIMreg] IANA, "Protocol Independent Multicast (PIM) Parameters",
<http://www.iana.org/assignments/pim-parameters>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2710] Deering, S., Fenner, W., and B. Haberman, "Multicast
Listener Discovery (MLD) for IPv6", RFC 2710, October
1999.
[RFC3376] Cain, B., Deering, S., Kouvelas, I., Fenner, B., and A.
Thyagarajan, "Internet Group Management Protocol, Version
3", RFC 3376, October 2002.
[RFC3810] Vida, R. and L. Costa, "Multicast Listener Discovery
Version 2 (MLDv2) for IPv6", RFC 3810, June 2004.
[RFC5790] Liu, H., Cao, W., and H. Asaeda, "Lightweight Internet
Group Management Protocol Version 3 (IGMPv3) and Multicast
Listener Discovery Version 2 (MLDv2) Protocols", RFC 5790,
February 2010.
[RFC6320] Wadhwa, S., Moisand, J., Haag, T., Voigt, N., and T.
Taylor, "Protocol for Access Node Control Mechanism in
Broadband Networks", RFC 6320, October 2011.
11.2. Informative References
[IEEE48] IEEE, "Guidelines for 48-Bit Global Identifier",
<http://standards.ieee.org/regauth/oui/tutorials/
EUI48.html>.
[IEEE64] IEEE, "Guidelines for 64-Bit Global Identifier",
<http://standards.ieee.org/regauth/oui/tutorials/
EUI64.html>.
[ITU-T_G.1080]
ITU-T, "Quality of experience requirements for IPTV
services", ITU-T Recommendation G.1080, December 2008.
[RFC2236] Fenner, W., "Internet Group Management Protocol, Version
2", RFC 2236, November 1997.
Le Faucheur, et al. Standards Track [Page 73]
RFC 7256 ANCP Multicast Extensions July 2014
[RFC4601] Fenner, B., Handley, M., Holbrook, H., and I. Kouvelas,
"Protocol Independent Multicast - Sparse Mode (PIM-SM):
Protocol Specification (Revised)", RFC 4601, August 2006.
[RFC5713] Moustafa, H., Tschofenig, H., and S. De Cnodder, "Security
Threats and Security Requirements for the Access Node
Control Protocol (ANCP)", RFC 5713, January 2010.
[RFC5851] Ooghe, S., Voigt, N., Platnic, M., Haag, T., and S.
Wadhwa, "Framework and Requirements for an Access Node
Control Mechanism in Broadband Multi-Service Networks",
RFC 5851, May 2010.
[RFC6614] Winter, S., McCauley, M., Venaas, S., and K. Wierenga,
"Transport Layer Security (TLS) Encryption for RADIUS",
RFC 6614, May 2012.
[RFC6733] Fajardo, V., Arkko, J., Loughney, J., and G. Zorn,
"Diameter Base Protocol", RFC 6733, October 2012.
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Appendix A. Example of Messages and Message Flows
This appendix provides an example in which most of the possible
message flows for multicast control are illustrated. This appendix
is for informational purposes only. In case of discrepancy with text
in the body of this document, the text in the body of the document is
to be considered as the normative text.
Assume the following, for a given access port:
o The basic subscribed service is white-listed. The AN will be
responsible for admission control for this service.
o Some premium services are available, but requests for these
services must be referred to the Policy Server for proper credit
processing. For this reason, they are grey-listed. The NAS will
be responsible for admission control for these services.
o The subscriber has asked that certain services be blocked so that
his children cannot view them. These services are black-listed.
o All of the above services are Source-Specific Multicast (SSM). In
addition, by means that bypass the AN, the subscriber can signal
intent to join an on-line game service that is Any-Source
Multicast (ASM). The NAS is responsible for admission control for
this service.
o Bandwidth delegation is, in effect, to share video bandwidth
between the AN and the NAS.
The stated conditions require the use of four of the five
capabilities specified in this memo.
A.1. Provisioning Phase
Assume that capability negotiation has been completed between the AN
and NAS and that the set of negotiated capabilities includes the
following four multicast capabilities: NAS-initiated multicast
replication, conditional access and admission control with white and
black lists, conditional access and admission control with grey
lists, and bandwidth delegation. At this point, the NAS can
provision the service profiles on the AN and enable admission control
at the AN for white-listed flows. To do this, the NAS sends the AN a
Provisioning message containing this information. An example message
providing the profile for our assumed subscriber is shown in
Figure 22. The message has the following contents:
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o Message Type is 93.
o The Result and Result Code fields in the header are set to zeroes,
as specified [RFC6320].
o A Transaction Identifier is assigned by the NAS.
o The Multicast-Service-Profile TLV (of which typically there would
be multiple instances) contains a Multicast-Service-Profile-Name
TLV (with a length of 20 octets assumed for the example) and three
List-Action TLVs, one each for the white, grey, and black lists
within the profile. The white list flows come in two sets of
group addresses: 233.252.0.0/29, coming from a server at
192.0.2.15, and 233.252.0.32/29, coming from a server at
192.0.2.16. The grey-listed flows are in the band
233.252.0.64/29, coming from a server at 192.0.2.21. Finally, the
black list flows are two individual flows that happen to overlap
with the grey list band: 233.252.0.65 and 233.252.0.69, also with
source 192.0.2.21.
o The White-List-CAC TLV indicates that the AN does admission
control on white-listed flows.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (0x880C) | Length = 132 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Msg Type = 93 | Res=0 | Result Code = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I| SubMessage Number | Length = 132 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mcast-Service-Profile 0x0013 | TLV Length = 112 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mcast-Svc-Profile-Name 0x0018 | Embedded TLV Length = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast service profile name |
~ = "Cust 0127-53681-0003" ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = List-Action 0x0021 | Embedded TLV Length = 28 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Operation = 1 | List Type = 1 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Family = 1 | List Length = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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| G PrefLen = 29| S PrefLen = 32| Group prefix = |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 233.252.0.0 | Source prefix = |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 192.0.2.15 | G PrefLen = 29| S PrefLen = 32|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group prefix = 233.252.0.32 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source prefix = 192.0.2.16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = List-Action 0x0021 | Embedded TLV Length = 18 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Operation = 1 | List Type = 3 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Family = 1 | List Length = 10 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G PrefLen = 29| S PrefLen = 32| Group prefix = /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ 233.252.0.64 | Source prefix = /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ 192.0.2.21 | Padding = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = List-Action 0x0021 | Embedded TLV Length = 28 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Operation = 1 | List Type = 2 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Address Family = 1 | List Length = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| G PrefLen = 32| S PrefLen = 32| Group prefix = /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ 233.252.0.65 | Source prefix = /
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
/ 192.0.2.21 | G PrefLen = 32| S PrefLen = 32|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Group prefix = 233.252.0.69 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Source prefix = 192.0.2.21 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = White-List-CAC 0x0024 | TLV Length = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 22: Example Provisioning Message
Note that the padding after the middle List-Action TLV is counted as
part of the length of the Multicast-Service-Profile TLV but is not
included in the length of that List-Action TLV. Note also that the
Length field in the message header, unlike those in the TLVs,
includes the message header itself, as required by [RFC6320].
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RFC 7256 ANCP Multicast Extensions July 2014
Finally, note that the Provisioning message does not include a
MRepCtl-CAC TLV since in our example admission control for grey-
listed flows and for NAS-initiated replication is performed by the
NAS.
As soon as the AN port comes up, the AN sends an ANCP PORT_UP message
to the NAS specifying the Access Loop Circuit ID. The NAS replies
with an ANCP Port Management message that, together with the other
parameters, includes the multicast service profile name to be
associated to that port along with the initial amount of delegated
bandwidth. The corresponding message flow is illustrated in
Figure 23.
+----------+ +---------+ +-----+ +-----+
|Subscriber| | Home | | AN | | NAS |
+----------+ | Gateway | +-----+ +-----+
| +---------+ | |
| | | |
| | | |
| | DSL Synch. | |
| |---------------->| |
| | |(M1)PORT_UP(Port ID) |
| | |-------------------->|
| | | (*)
| | |(M2) PORT_MNGT |
| | | (Port ID, |
| | |Mcast S Profile Name,|
| | |Bandwidth Allocation)|
| | |<--------------------|
(*) The NAS may optionally seek direction from an external
Authorization/Policy Server
Figure 23: Configuring an AN Port with Multicast Service Profile ID
and Delegated Bandwidth Amount
The Port Management message will typically contain other TLVs, but
our example (Figure 24) just shows the Target, Multicast-Service-
Profile-Name, and Bandwidth-Allocation TLVs. The Target TLV
identifies the subscriber line, the Multicast-Service-Profile-Name
TLV is identical to the one contained in the Provisioning message,
and the Bandwidth-Allocation TLV provides just enough bandwidth (2000
kbits/s) for one channel to start with.
The following fields in the Port Management message header are shown
with specific values either as directed by the base protocol document
or for the sake of our example:
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o Message Type is 32.
o Result is set to Nack (0x1) for this example.
o Result Code is 0.
o A Transaction Identifier is assigned by the NAS.
o Port is set to 0.
o Event Sequence Number, the R flag and the other bits marked x,
Duration, the Event Flags, and the Flow Control Flags are all
irrelevant for this function and are set to 0.
o Function is set to "Configure Connection Service Data" (8).
o X-Function is set to 0.
o Tech Type is "DSL" (5).
o Block lengths are calculated assuming a Circuit-Id length of 4 in
our example. Recall that the example Multicast-Service-Profile-
Name TLV length is 20.
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1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (0x880C) | Length = 84 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Msg Type = 32 | Res=1 | Result Code = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I| SubMessage Number | Length = 84 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Port Session Number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Event Sequence Number = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R|x|x|x|x|x|x|x| Duration = 0 | Function = 0x8| X-Function = 0|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Event Flags | Flow Control Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|x|x|x|x|x|x|x|x| Msg Type = 32 | Tech Type=5 | Blk Len = 56 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| # of TLVs = 3 | Extension Block length = 44 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access Loop Circuit ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mcast-Svc-Profile-Name 0x0018 | TLV Length = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast service profile name |
~ = "Cust 0127-53681-0003" ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth-Allocation 0x0015 | TLV Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth value = 2000 (kbits/s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 24: Example Port Management Message
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A.2. Handling Grey-Listed Flows
Suppose now that the subscriber chooses to watch the premium channel
characterized by source 192.0.2.21, group 233.252.0.67. Upon
receiving the join request, the AN matches it against the multicast
service profile for the port and determines that it is a grey-listed
flow. Figure 25 illustrates the resulting ANCP message flow for the
case of a simple join and leave, when admission control for grey-
listed flows is not activated on the AN.
To start the flow, the AN sends a Multicast Admission Control message
(M1) to the NAS. The NAS decides whether the flow can be admitted,
applying both policy and bandwidth criteria. It returns its decision
(positive in this example) in a Multicast Replication Control message
(M2). Later, when the subscriber leaves the flow, the AN informs the
NAS by sending another Multicast Admission Control message.
+----------+ +-------+ +-----+ ANCP +-----+
|Subscriber| | Home | | AN |<---------->| NAS |
+----------+ |Gateway| +-----+ +-----+
| +-------+ | |
| | | Multicast |
| Join(Grey-Fl) | Admission |
|-----------+---------->| Control (M1) |
| | |------------------>|
| | | | (NAS performs
| | | Multicast | admission
| | | Replication (*) control)
| | | Control (M2) |
| Mcast Grey Flow |<------------------|
|<======================+ |
| | | |
~ ~ ~ ~
| | | Multicast |
| Leave(Grey-Fl) | Admission |
|-----------+---------->| Control (M3) |
| | |------------------>|
| | | |
Grey-Fl: multicast flow matching an entry in grey list
(*) The NAS may optionally seek direction from an external
Authorization/Policy Server.
Figure 25: Successful Join/Leave Operations, Grey-Listed Flow
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RFC 7256 ANCP Multicast Extensions July 2014
The Multicast Admission Control message M1 contains:
o an ANCP Header with:
* Message Type is 145;
* Result = Ignore (0x0); and
* a Transaction Identifier assigned by the AN.
o a Target TLV identifying the AN Port
o a Command TLV containing:
* Command Code = "Add" (1);
* Accounting = "No" (0);
* a Multicast-Flow embedded TLV indicating the multicast flow for
which the AN received the IGMP join: flow type "SSM" (2),
address family "IPv4" (1), Group address = 233.252.0.67, Source
Address = 192.0.2.21; and
* a Request-Source-Device-Id embedded TLV containing the IGMP
join source local device identifier value 5.
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The Multicast Admission Control message M1 is illustrated in
Figure 26:
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (0x880C) | Length = 98 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Msg Type=145 | Res=0 | Result Code = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I| SubMessage Number | Length = 98 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access Loop Circuit ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Command 0x0011 | TLV Length = 28 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cmd Code = 1 | Acctg = 0 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = Multicast-Flow 0x0019 | Embedded TLV Length = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow Type = 2 | Addr Fam = 1 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast Group Address = 233.252.0.67 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unicast Source Address = 192.0.2.21 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+--+
|Request-Source-Device-Id 0x0092| Embedded TLV length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value = 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 26: Multicast Admission Control Message Seeking to Add a Flow
The Multicast Replication Control message M2 contains:
o an ANCP Header with:
* Message Type = "Multicast Replication Control" (144);
* Result= 0x1 (Nack); and
* a Transaction Identifier assigned by the NAS;
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RFC 7256 ANCP Multicast Extensions July 2014
o a Target TLV identifying the AN Port
o a Command TLV containing:
* Command Code = "Add" (1);
* Accounting = "Yes" (1), since in our example the operator wants
accounting on this flow; and
* a Multicast-Flow embedded TLV indicating the multicast flow
that the NAS is admitting for this access line: flow type "SSM"
(2), address family "IPv4" (1), Group address = 233.252.0.67,
Source Address = 192.0.2.21.
The Multicast Admission Control message M2 is illustrated in
Figure 27.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (0x880C) | Length = 48 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Msg Type=144 | Res=1 | Result Code = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I| SubMessage Number | Length = 48 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Target Type = 0x1000 | Target TLV Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access Loop Circuit ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Command 0x0011 | TLV Length = 20 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cmd Code = 1 | Acctg = 1 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = Multicast-Flow 0x0019 | Embedded TLV Length = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow Type = 2 | Addr Fam = 1 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast Group Address = 233.252.0.67 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unicast Source Address = 192.0.2.21 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 27: Multicast Replication Control Message Admitting a Flow
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RFC 7256 ANCP Multicast Extensions July 2014
The Multicast Admission Control message M3 advising the NAS that the
flow has been terminated contains:
o an ANCP Header with:
* Message Type is 145;
* Result = Ignore (0x0); and
* a Transaction Identifier assigned by the AN.
o a Target TLV identifying the access line
o a Command TLV containing:
* a Command Code = "Delete" (2);
* Accounting = "No" (0);
* a Multicast-Flow embedded TLV indicating the multicast flow for
which the AN received the IGMP leave: flow type "SSM" (2),
address family "IPv4" (1), Group address = 233.252.0.67, Source
Address = 192.0.2.21; and
* a Request-Source-Device-Id embedded TLV containing the IGMP
leave request source, the device identified by the local value
5.
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RFC 7256 ANCP Multicast Extensions July 2014
The Multicast Admission Control message M3 is illustrated in
Figure 28.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (0x880C) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Msg Type=145 | Res=0 | Result Code = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I| SubMessage Number | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access Loop Circuit ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Command 0x0011 | TLV Length = 28 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cmd Code = 2 | Acctg = 0 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast-Flow Type = 0x0019 | Embedded TLV Length = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow Type = 2 | Addr Fam = 1 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast Group Address = 233.252.0.67 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unicast Source Address = 192.0.2.21 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|Request-Source-Device-Id 0x0092| Embedded TLV length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Value = 5 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 28: Multicast Admission Control Message Signaling Flow
Termination
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RFC 7256 ANCP Multicast Extensions July 2014
A.3. Handling White-Listed Flows
The NAS has enabled white list admission control on the AN, and the
bandwidth delegation capability has been negotiated. White-listed
flows in themselves require no messages to the NAS, either upon
admission or upon termination, but the AN may request an increase in
the amount of delegated bandwidth if it needs the increase to admit a
flow.
Consider an example where the AN has already admitted one white-
listed flow, thereby using up the initially provisioned amount of
delegated bandwidth (2000 kbits/s). A request is received to join a
new flow in the white list range. The AN chooses to send a Bandwidth
Reallocation Request message to the NAS, requesting that the
delegated bandwidth allocation be increased to 4000 kbits/s at a
minimum and preferably to 6000 kbits/s.
In our example, the NAS is managing bandwidth tightly, as witnessed
by its minimal initial allocation of just enough for one flow. It is
willing to provide the minimum additional amount only and therefore
returns a Bandwidth Transfer message where the delegated bandwidth
value is given as 4000 kbits/s. With this amount, the AN is able to
admit the second white-listed flow. The AN could send a similar
Bandwidth Transfer message back to the NAS bringing the delegated
bandwidth amount back down to 2000 kbits/s when one of the flows is
terminated, but this shows nothing new and is omitted.
As one more point of illustration, suppose that the NAS chooses to
audit the current amount of delegated bandwidth to ensure it is
synchronized with the AN. It sends a Delegated Bandwidth Query
Request message to the AN and receives a Delegated Bandwidth Query
Response message with the current allocation as the AN sees it.
The complete message flow is shown in Figure 29.
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RFC 7256 ANCP Multicast Extensions July 2014
+----------+ +-------+ +-----+ ANCP +-----+
|Subscriber| | Home | | AN |<---------->| NAS |
+----------+ |Gateway| +-----+ +-----+
| +-------+ | |
| | | |
| Join(White-F1) | |
|-----------+---------->| |
| | |AN performs |
| Mcast White Flow 1 | admission control |
|<======================+ |
| | | |
| Join(White-F2) | |
|-----------+---------->|No bandwidth left |
| | | |
| | |Bandwidth |
| | | Reallocation Req |
| | |------------------>|(M1)
| | | |
| | | (*)
| | |Bandwidth Transfer |
| AN can now |<------------------|(M2)
| admit flow | |
| Mcast White Flow 2 | |
|<======================+ |
| | | |
~ ~ ~ ~
| | |Delegated Bandwidth|
| | | Query request |
| | |<------------------|(M3)
| | | |
| | |Delegated Bandwidth|
| | | Query response |
| | |------------------>|(M4)
| | | |
(*) The NAS may optionally seek direction from an external
Authorization/Policy Server.
Figure 29: Successful Join/Leave Operations, White-Listed Flow
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RFC 7256 ANCP Multicast Extensions July 2014
The Bandwidth Reallocation Request message (M1) is shown in
Figure 30. The contents require little explanation. The Message
Type for the Bandwidth Reallocation Request is 146. The Result field
is set to Ignore (0x0). Besides the Target TLV, the message has one
other TLV, the Bandwidth-Request, with a TLV Type of 0x0016. The TLV
contains Required Amount and Preferred Amount fields, set to 4000 and
6000 kbits/s respectively.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (0x880C) | Length = 36 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Msg Type=146 | Res=0 | Result Code = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I| SubMessage Number | Length = 36 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access Loop Circuit ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth-Request 0x0016 | TLV Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Required Amount = 4000 (kbits/s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Preferred Amount = 6000 (kbits/s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 30: Bandwidth Reallocation Request Message
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RFC 7256 ANCP Multicast Extensions July 2014
The Bandwidth Transfer message (M2) is shown in Figure 31. Again,
the contents are easily understood. The Message Type for the
Bandwidth Transfer message is 147. The Result field is set to
Success (0x3). The message contains the Target TLV and the
Bandwidth-Allocation TLV. The latter has a TLV Type of 0x0015 and
contains a Delegated Amount field, set to 4000 kbits/s.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (0x880C) | Length = 32 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Msg Type=147 | Res=3 | Result Code = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I| SubMessage Number | Length = 32 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access Loop Circuit ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth-Allocation 0x0015 | TLV Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Delegated Amount = 4000 (kbits/s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 31: NAS Response, Bandwidth Transfer Message
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The Delegated Bandwidth Query Request message (M3) is shown in
Figure 32. The Message Type for the Delegated Bandwidth Query
request message is 148. The Result field is set to AckAll (0x2).
The message contains the Target TLV only.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (0x880C) | Length = 24 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Msg Type=148 | Res=2 | Result Code = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I| SubMessage Number | Length = 24 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access Loop Circuit ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 32: Delegated Bandwidth Query Request Message
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RFC 7256 ANCP Multicast Extensions July 2014
Finally, the Delegated Bandwidth Query Response message (M4) is shown
in Figure 33. The Message Type for the Delegated Bandwidth Query
response message is 148. The Result field is set to Success (0x3).
The message contains the Target TLV and the Bandwidth-Allocation TLV
with the Delegated Amount field set to 4000 kbits/s.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (0x880C) | Length = 32 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Msg Type=148 | Res=3 | Result Code = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier (copied from request) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I| SubMessage Number | Length = 32 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access Loop Circuit ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Bandwidth-Allocation 0x0015 | TLV Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Delegated Amount = 4000 (kbits/s) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 33: Delegated Bandwidth Query Response Message
A.4. Handling of Black-Listed Join Requests
This section introduces no new messages, since requests for flows in
the black list are simply ignored. The one thing to point out is the
overlap in our example between the set of flows in the grey list and
the flows in the black list. This does not create any ambiguity,
since not only does the black list have priority for equally good
matches, but also the black list entries are more specific (group
prefix lengths of 32 versus 29 in the grey list) than the grey list
flow prefixes.
A.5. Handling of Requests to Join and Leave the On-Line Game
The final class of multicast control actions in our example allows
the subscriber to enter and leave the on-line game. As described at
the beginning of this example, the game uses Any-Source Multicast
(ASM). Subscriber signaling bypasses the AN, going directly to the
NAS (e.g., through a web interface).
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When the subscriber requests to join the game, the NAS (after
applying policy and bandwidth checks) sends a Multicast Replication
Control message to the AN to enable the flow on the port concerned.
The AN knows not to apply admission control, since it has not
received an MRepCtl-CAC TLV in the Provisioning message. When the
subscriber leaves, the NAS sends another Multicast Replication
Control message to delete the flow. This message sequence is shown
in Figure 34.
It is possible that the NAS finds that there is not enough bandwidth
available to accommodate the subscriber's request. In this case, the
NAS could send a Bandwidth Reallocation Request message to the AN,
asking it to release some of the bandwidth delegated to it. This is
not shown in the present example, since the messages are the same as
those already presented with the exception that the Preferred Amount
in the request will be *less than* or equal to the Required amount,
rather than *greater than* or equal to it.
+----------+ +-------+ +-----+ ANCP +-----+
|Subscriber| | Home | | AN |<---------->| NAS |
+----------+ |Gateway| +-----+ +-----+
| +-------+ | |
| | | |
| Join game | |
|-----------+------------------------------>|
| | | Multicast | NAS performs
| | | Replication (*) admission
| | | Control (M1) | control
| Mcast Game Flow |<------------------|
|<=====================>+ |
| | | |
~ ~ ~ ~
| | | |
| Leave game | |
|-----------+------------------------------>|
| | | Multicast |
| | | Replication |
| | | Control (M2) |
| Mcast Game Flow |<------------------|
| discontinued | |
| | | |
(*) The NAS may optionally seek direction from an external
Authorization/Policy Server.
Figure 34: NAS-Initiated Flows for On-Line Gaming
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The Multicast Replication Control message (M1) in Figure 35 looks
like the message in Figure 27 with two exceptions. The first is that
the NAS has the option to set the Result field to AckAll (0x02) if it
needs positive reassurance that the flow has been enabled. This was
not done here to save having to depict a response differing only in
the Result field. The larger difference in this example is that the
flow description in the Multicast-Flow embedded TLV is that of an ASM
multicast group (Flow Type = 1) with IPv4 (1) group address
233.252.0.100.
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (0x880C) | Length = 44 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Msg Type=144 | Res=1 | Result Code = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I| SubMessage Number | Length = 44 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length = 8 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length = 4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access Loop Circuit ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Command 0x0011 | TLV Length = 16 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Cmd Code = 1 | Acctg = 1 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = Multicast-Flow 0x0019 | Embedded TLV Length = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow Type = 1 | Addr Fam = 1 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast Group Address = 233.252.0.100 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+--+
Figure 35: Enabling the Subscriber to Join an On-Line Game
Message M2 terminating the flow when the subscriber leaves the game
looks the same as the message in Figure 35 with two exceptions: the
Command Code becomes "Delete" (2), and Accounting is set to "No" (0)
to turn off flow accounting. Of course, the Transaction Identifier
values will differ between the two messages.
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A.6. Example Flow for Multicast Flow Reporting
The example in this section is independent of the example in the
preceding sections.
Figure 36 illustrates a message flow in a case where the NAS queries
the AN about which multicast flows are active on port 10, port 11,
and port 20 of the AN.
+----------+ +-------+ +-----+ ANCP +-----+
|Subscriber| | Home | | AN |<---------->| NAS |
+----------+ |Gateway| +-----+ +-----+
| +-------+ | |
| | | Multicast Flow |
| | | Query Request |
| | | (M1) |
| | |<------------------|
| | | |
| | | Multicast Flow |
| | | Query Response |
| | | (M2) |
| | |------------------>|
| | | |
| | | |
Figure 36: Per-Port Multicast Flow Reporting
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The Multicast Flow Query Request message (M1) is illustrated in
Figure 37. The Message Type is 149. The Result field is set to
AckAll (0x2). Three Target TLVs are present, identifying port 10,
port 20, and port 11, respectively.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (0x880C) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Msg Type = 149| Res=2 | Result Code = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I| SubMessage Number | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Access Loop Circuit ID (port10) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Access Loop Circuit ID (port20) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Access Loop Circuit ID (port11) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 37: Multicast Flow Query Request Message for Per-Port
Multicast Flow Reporting
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The Multicast Flow Query Response message (M2) is illustrated in
Figure 38. It indicates that there is one active multicast flow
[(192.0.2.1, 233.252.0.4)] on port 10, no active multicast flow on
port 20, and two active multicast flows [(192.0.2.1, 233.252.0.4) and
(192.0.2.2, 233.252.0.10)] on port 11.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type (0x880C) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Version | Msg Type = 149|Rslt=3 | Result Code = 0 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Partition ID | Transaction Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|I| SubMessage Number | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Access Loop Circuit ID (port10) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = Multicast-Flow 0x0019 | Embedded TLV Length = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow Type = 2 | Addr Fam = 1 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast Group Address = 233.252.0.4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unicast Source Address = 192.0.2.1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+--+
| TLV Type = Target 0x1000 | Target TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Access Loop Circuit ID (port20) ~
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TLV Type = Target 0x1000 | Target TLV Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Access-Loop-Circuit-ID 0x0001 | Circuit-ID Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
~ Access Loop Circuit ID (port11) ~
| |
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+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type = Multicast-Flow 0x0019 | Embedded TLV Length = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow Type = 2 | Addr Fam = 1 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast Group Address = 233.252.0.4 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unicast Source Address = 192.0.2.1 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+--+
| Type = Multicast-Flow 0x0019 | Embedded TLV Length = 12 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flow Type = 2 | Addr Fam = 1 | Reserved = 0x0000 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Multicast Group Address: 233.252.0.10 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Unicast Source Address = 192.0.2.2 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++-+-+-+-+-+--+
Figure 38: Multicast Flow Query Response Message for Per-Port
Multicast Flow Reporting
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Authors' Addresses
Francois Le Faucheur
Cisco Systems
45 Allee des Ormes
Mougins 06250
France
Phone: +33 4 97 23 26 19
EMail: flefauch@cisco.com
Roberta Maglione
Cisco Systems
181 Bay Street
Toronto, ON M5J 2T3
Canada
EMail: robmgl@cisco.com
Tom Taylor
Huawei Technologies
Ottawa
Canada
EMail: tom.taylor.stds@gmail.com
Le Faucheur, et al. Standards Track [Page 99]