Generic Aggregation of Resource ReSerVation Protocol (RSVP) for IPv4 And IPv6 Reservations over PCN domains
draft-ietf-tsvwg-rsvp-pcn-00
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft that was ultimately published as RFC 7417.
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|---|---|---|---|
| Authors | Georgios Karagiannis , Anurag Bhargava | ||
| Last updated | 2011-10-08 | ||
| RFC stream | Internet Engineering Task Force (IETF) | ||
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draft-ietf-tsvwg-rsvp-pcn-00
Internet Engineering Task Force Georgios Karagiannis
Internet-Draft University of Twente
Intended status: Standards Track Anurag Bhargava
Expires: April 08, 2012 Cisco Systems, Inc.
October 08, 2011
Generic Aggregation of Resource ReSerVation Protocol (RSVP)
for IPv4 And IPv6 Reservations over PCN domains
draft-ietf-tsvwg-rsvp-pcn-00
Abstract
This document specifies the extensions to the Generic Aggregated RSVP
[RFC4860] for support of the PCN Controlled Load (CL) and Single
Marking (SM) edge behaviors over a Diffserv cloud using Pre-
Congestion Notification.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 08, 2012.
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Copyright Notice
Copyright (c) 2011 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.
Requirements Language
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 RFC 2119 [RFC2119].
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . .
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . .
2. Overview of RSVP extensions and Operations . . . . . . . . . . . . .
2.1 Overview of RSVP Aggregation Procedures in PCN domains . . . . . . .
2.1.1 PCN Marking and encoding and transport of pre-congestion
Information . . . . . . . . . . . . . . . . . . . . . . . . . .
2.1.2. Traffic Classification Within The Aggregation Region . . . . . .
2.1.3. Deaggregator (PCN-egress-node) Determination . . . . . . . . . .
2.1.4. Mapping E2E Reservations Onto Aggregate Reservations . . . . . .
2.1.5. Size of Aggregate Reservations . . . . . . . . . . . . . . . . .
2.1.6. E2E Path ADSPEC update . . . . . . . . . . . . . . . . . . . . .
2.1.7. Intra-domain Routes . . . . . . . . . . . . . . . . . . . . . .
2.1.8. Inter-domain Routes
2.1.9. Reservations for Multicast Sessions . . . . . . . . . . . . . .
2.1.10. Multi-level Aggregation . . . . . . . . . . . . . . . . . . . .
2.1.11. Reliability Issues . . . . . . . . . . . . . . . . . . . .
2.1.12. Message Integrity and Node Authentication . . . . . . . . . .
3. Elements of Procedure . . . . . . . . . . . . . . . . . . . . . . . .
3.1. Receipt of E2E Path Message By PCN-ingress-node
(aggregating router) . . . . . . . . . . . . . . . . . . . . . . .
3.2. Handling Of E2E Path Message By Interior Routers . . . . . . . . .
3.3. Receipt of E2E Path Message By PCN-egress-node
(deaggregating router) . . . . . . . . . . . . . . . . . . . . . .
3.4. Initiation of new Aggregate Path Message By PCN-ingress node
(Aggregating Router) . . . . . . . . . . . . . . . . . . . . . . .
3.5. Handling Of new Aggregate Path Message By Interior Routers . . . .
3.6. Handling of E2E Resv Message by Deaggregating Router . . . . . . .
3.7. Handling Of E2E Resv Message By Interior Routers . . . . . . . . .
3.8. Initiation of New Aggregate Resv Message By Deaggregating Router .
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3.9. Handling of Aggregate Resv Message by Interior Routers . . . . . .
3.10. Handling of E2E Resv Message by Aggregating Router . . . . . . .
3.11. Handling of Aggregated Resv Message by Aggregating Router . . . .
3.12. Removal of E2E Reservation . . . . . . . . . . . . . . . . . . .
3.13. Removal of Aggregate Reservation . . . . . . . . . . . . . . . .
3.14. Handling of Data On Reserved E2E Flow by Aggregating Router . . .
3.15. Procedures for Multicast Sessions . . . . . . . . . . . . . . . .
4. Protocol Elements . . . . . . . . . . . . . . . . . . . . . . . . .
4.1 PCN object . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5. Security Considerations . . . . . . . . . . . . . . . . . . . . . .
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . . .
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . .
8. Normative References . . . . . . . . . . . . . . . . . . . . . . . .
9. Informative References . . . . . . . . . . . . . . . . . . . . . . .
10. Authors' Address . . . . . . . . . . . . . . . . . . . . . . . . .
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1. Introduction
Two main Quality of Service (QoS) architectures have been specified
By the IETF. These are the Integrated Services (Intserv) [RFC1633]
architecture and the Differentiated Services (DiffServ) architecture
([RFC2475]).
Intserv provides methods for the delivery of end-to-end Quality of
Service (QoS) to applications over heterogeneous networks. One of the
QoS signaling protocols used by the Intserv architecture is the
Resource reServation Protocol (RSVP) [RFC2205], which can be used by
applications to request per-flow resources from the network. These
RSVP requests can be admitted or rejected by the network.
Applications can express their quantifiable resource requirements
using Intserv parameters as defined in [RFC2211] and [RFC2212]. The
Controlled Load (CL) service [RFC2211] is a quality of service (QoS)
closely approximating the QoS that the same flow would receive from a
lightly loaded network element. The CL service is useful for
inelastic flows such as those used for real-time media.
The DiffServ architecture can support the differentiated treatment of
packets in very large scale environments. While Intserv and RSVP
classify packets per-flow, Diffserv networks classify packets into
one of a small number of aggregated flows or "classes", based on the
Diffserv codepoint (DSCP) in the packet IP header. At each Diffserv
router, packets are subjected to a "per-hop behavior" (PHB), which is
invoked by the DSCP. The primary benefit of Diffserv is its
scalability, since the need for per-flow state and per-flow
processing, is eliminated.
However, DiffServ does not include any mechanism for communication
between applications and the network. Several solutions have been
specified to solve this issue. One of these solutions is Intserv over
Diffserv [RFC2998] including resource-based admission control,
policy-based admission control, assistance in traffic
identification/classification, and traffic conditioning.
Intserv over Diffserv can operate over a statically provisioned
Diffserv region or RSVP aware. When it is RSVP aware, several
mechanisms may be used to support dynamic provisioning and topology-
Aware admission control, including aggregate RSVP reservations, per-
flow RSVP, or a bandwidth broker.
RFC 3175 [RFC3175] specifies aggregation of Resource ReSerVation
Protocol (RSVP) end-to-end reservations over aggregate RSVP
reservations. In [RFC3175] the RSVP aggregated reservation is
characterized by a RSVP SESSION object using the 3-tuple <source IP
address, destination IP address, Diffserv Code Point>.
[RFC4860] provides generic aggregate reservations by extending
[RFC3175] to support multiple aggregate reservations for the same
source IP address, destination IP address, and PHB (or set of PHBs).
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In particular, multiple such generic aggregate reservations can be
established for a given PHB (or set of PHBs) from a given source IP
address to a given destination IP address. This is achieved by adding
the concept of a Virtual Destination Port and of an Extended Virtual
Destination Port in the RSVP SESSION object. In addition to this, the
RSVP SESSION object for generic aggregate reservations uses the
PHB Identification Code (PHB-ID) defined in [RFC3140], instead of
using the Diffserv Code Point (DSCP) used in [RFC3175]. The PHB-ID is
used to identify the PHB, or set of PHBs, from which the Diffserv
resources are to be reserved. This is among others used to specify
whether the Diffserv resources belong to a single PHB or to a set of
PHBs.
The main objective of Pre-Congestion Notification (PCN) is to support
the quality of service (QoS) of inelastic flows within a Diffserv
domain in a simple, scalable, and robust fashion. Two mechanisms
are used: admission control and flow termination. Admission control
is used to decide whether to admit or block a new flow request while
flow termination is used in abnormal circumstances to decide
whether to terminate some of the existing flows. To support these
two features, the overall rate of PCN-traffic is metered on every
link in the domain, and PCN-packets are appropriately marked when
certain configured rates are exceeded. These configured rates are
below the rate of the link thus providing notification to boundary
nodes about overloads before any congestion occurs (hence "pre-
congestion" notification).
The PCN-egress-nodes measure the rates of differently marked
PCN-traffic in periodic intervals and report these rates to the
decision points for admission control and flow termination, based on
which they take their decisions. The decision points may be
collocated with the PCN-ingress-nodes or their function may be
implemented in a centralized node.
For more details see[RFC5559], [draft-ietf-pcn-cl-edge-behaviour-09],
[draft-ietf-pcn-sm-edge-behaviour-06]. In this document it is
Considered that the decision point is collocated with the PCN-
ingress-node.
This document follows the PCN signaling requirements defined in
[draft-ietf-pcn-signaling-requirements-06.txt] and specifies the
extensions to the Generic Aggregated RSVP [RFC4860] for the support
of PCN edge behaviours as specified in [draft-ietf-pcn-cl-edge-
behaviour-09] and [draft-ietf-pcn-sm-edge-behaviour-06]. Moreover,
this document specifies how RSVP aggregation can be used to setup and
maintain: (1) Ingress Egress Aggregate (IEA) states at Ingress and
Egress nodes and (2) generic aggregation of RSVP end-to-end RSVP
reservations over PCN (Congestion and Pre-Congestion Notification)
domains.
This document, and according to [RFC4860] MAY also
be used end-to-end directly by end-systems attached to a Diffserv
network.
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Furthermore, this document and according to [RFC4860], in absence of
e2e RSVP flows, a variety of policies (not defined in this document)
can be used at the Aggregator to set the DSCP of packets passing into
the aggregation region and how they are mapped onto generic aggregate
reservations. These policies are not described in this document but
are a matter of local configuration.
In this document it is considered that the PCN-nodes MUST be able to
support the functionality specified in [RFC5670], [RFC5559],
[RFC5696],[draft-ietf-pcn-cl-edge-behaviour-09], [draft-ietf-pcn-sm-
edge-behaviour-06]. Furthermore, the PCN-boundary-nodes MUST support
the RSVP generic aggregated reservation procedures specified in
[RFC4860] which are augmented with procedures specified in this
document.
1.1. Terminology
This document uses terms defined in [RFC4860], [RFC3175], [RFC5559],
[RFC5670], [draft-ietf-pcn-cl-edge-behaviour-09],
[draft-ietf-pcn-sm-edge-behaviour-06].
For readability, a number of definitions from [RFC3175] as well as
definitions for terms used in [RFC5559], [draft-ietf-pcn-cl-edge-
behaviour-09], and [draft-ietf-pcn-sm-edge-behaviour-06] are provided
here, where some of them are augmented with new meanings:
Aggregator This is the process in (or associated with) the
router at the ingress edge of the aggregation region
(with respect to the end-to-end RSVP reservation)
and behaving in accordance with [RFC4860]. In this
document, it is also the PCN-ingress-node and the
decision point.
Deaggregator This is the process in (or associated with) the
router at the egress edge of the aggregation region
(with respect to the end-to-end RSVP reservation)
and behaving in accordance with [RFC4860]. In this
document, it is also the PCN-egress-node.
E2E End to end
E2E Reservation This is an RSVP reservation such that:
(i) corresponding RSVP Path messages are initiated
upstream of the Aggregator and terminated
downstream of the Deaggregator, and
(ii) corresponding RSVP Resv messages are initiated
downstream of the Deaggregator and terminated
upstream of the Aggregator, and
(iii) this RSVP reservation is aggregated over an
Ingress Egress Aggregate (IEA) between the
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Aggregator and
Deaggregator An E2E RSVP reservation may be a per-flow
reservation, which in this document is only
maintained at the PCN-ingress-node and PCN-egress-
node. Alternatively, the E2E reservation may itself
be an aggregate reservation of various types (e.g.,
Aggregate IP reservation, Aggregate IPsec
reservation, see [RFC4860]). As per regular RSVP
operations, E2E RSVP reservations are
unidirectional.
PHB-ID (Per Hop Behavior Identification Code)
A 16-bit field containing the Per Hop Behavior
Identification Code of the PHB, or of the set of
PHBs, from which Diffserv resources
are to be reserved. This field MUST be encoded as
specified in Section 2 of [RFC3140].
VDstPort (Virtual Destination Port)
A 16-bit identifier used in the SESSION that
remains constant over the life of the generic
aggregate reservation.
Extended vDstPort (Extended Virtual Destination Port)
A 32-bit identifier used in the SESSION that
remains constant over the life of the generic
aggregate reservation. A sender (or Aggregator)
that wishes to narrow the scope of a SESSION to the
sender-receiver pair (or Aggregator-Deaggregator
pair) SHOULD place its IPv4 or IPv6 address here as
a network unique identifier. A sender (or
Aggregator) that wishes to use a common session
with other senders (or Aggregators) in order to use
a shared reservation across senders (or
Aggregators) MUST set this field to all zeros.
In this document, the Extended vDstPort SHOULD
contain the IPv4 or IPv6 address of the Aggregator.
PCN-domain: a PCN-capable domain; a contiguous set of
PCN-enabled nodes that perform Diffserv scheduling
[RFC2474]; the complete set of PCN-nodes that in
principle can, through PCN-marking packets,
influence decisions about flow admission and
termination for the PCN-domain; includes
the PCN-egress-nodes, which measure these
PCN-marks, and the PCN-ingress-nodes.
PCN-boundary-node: a PCN-node that connects one PCN-domain to a node
either in another PCN-domain or in a non-PCN-domain.
PCN-interior-node: a node in a PCN-domain that is not a PCN-
boundary-node.
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PCN-node: a PCN-boundary-node or a PCN-interior-node.
PCN-egress-node: a PCN-boundary-node in its role in handling
traffic as it leaves a PCN-domain.
PCN-ingress-node: a PCN-boundary-node in its role in handling
traffic as it enters a PCN-domain. In this
document the PCN-ingress-node operates also as a
Decision Point and aggregator.
PCN-traffic,
PCN-packets,
PCN-BA: a PCN-domain carries traffic of different Diffserv
behaviour aggregates (BAs) [RFC2474]. The PCN-BA
uses the PCN mechanisms to carry PCN-traffic, and
the corresponding packets are PCN-packets.
The same network will carry traffic of other
Diffserv BAs. The PCN-BA is
distinguished by a combination of the Diffserv
codepoint (DSCP) and ECN fields.
PCN-flow: the unit of PCN-traffic that the PCN-boundary-node
admits (or terminates); the unit could be a single
microflow (as defined in [RFC2474]) or some
identifiable collection of microflows.
Ingress-egress-aggregate (IEA):
The collection of PCN-packets from all PCN-flows
that travel in one direction between a specific pair
of PCN-boundary-nodes. An ingress-
egress-aggregate is identified by the
combination of (1) fields), (2) IP addresses of the
specific pair of PCN-boundary-nodes used by a
ingress-egress-aggregate. In this document the
ingress-egress-aggregate is associated with a RSVP
generic aggregated reservation state [RFC4860].
PCN-admission-state
The state ("admit" or "block") derived by the
Decision Point (PCN-ingress-node) for a given
ingress-egress-aggregate based on PCN packet marking
statistics. The Decision Point decides to admit or
block new flows offered to the aggregate based on
the current value of the PCN-admission-state.
Congestion level estimate (CLE)
The ratio of PCN-marked to total PCN-traffic
(measured in octets) received for a given ingress-
egress-aggregate during a given measurement period.
The CLE is used to derive the PCN-admission-state
and is also used by the report suppression procedure
if report suppression is activated.
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T-meas
A configurable time interval that defines the
measurement period over which the PCN-egress-node
collects statistics relating to PCN-traffic
marking.
At the end of the interval the PCN-egress-node
calculates the values NM-rate, ThM-rate,
and ETM-rate as defined and sends a report to the
Decision Point, subject to the operation of the
Report suppression feature.
T-maxsuppress
A configurable time interval after which the PCN-
egress-node MUST send a report to the Decision
Point for a given ingress-egress-aggregate
regardless of the most recent values of the CLE.
This mechanism provides the Decision Point with a
Periodic confirmation of liveness when report
suppression is activated.
T-fail
A configurable interval after which the Decision
Point Concludes that communication from a given PCN-
egress-node has failed if it has received no reports
from the PCN-egress-node during that interval.
t-recvFail
An ingress-egress-aggregate timer that is used at
The Decision point (in this document at the PCN-
ingress-node) which when expires raises an alarm to
management, and activates the PCN-ingress-node to
block the admission of new PCN-flows. This timer
expires when it value is equal to T-fail and is
reset when a report, i.e., RSVP aggregated RESV
message, is received for the ingress-egress-
aggregate.
2. Overview of RSVP extensions and Operations
2.1 Overview of RSVP Aggregation Procedures in PCN domains
The PCN-boundary-nodes, see Figure 1, can support RSVP SESSIONS for
generic aggregated reservations {RFC4860], which are depending on
ingress-egress-aggregates. In particular, an ingress-egress-aggregate
matches to only one RSVP SESSION for generic aggregated reservations.
However, a RSVP SESSION for generic aggregated reservations can match
to one or more than one ingress-egress-aggregates. This can be
accomplished by using for the different ingress-egress-aggregates the
same combinations of ingress and egress identifiers, but with a
different PHB-ID value (see [RFC4860]).
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--------------------------
/ PCN-domain \
|----| | | |----|
H--| R |\ |-----| |------| /| R |-->H
H--| |\\| | |---| |---| | |//| |-->H
|----| \| | | I | | I | | |/ |----|
| Agg |======================>| Deag |
/| | | | | | | |\
H--------//| | |---| |---| | |\\-------->H
H--------/ |-----| |------| \-------->H
| |
\ /
--------------------------
H = Host requesting end-to-end RSVP reservations
R = RSVP router
Agg = Aggregator (PCN-ingress-node)
Deag = Deaggregator (PCN-egress-node)
I = Interior Router (PCN-interior-node)
--> = E2E RSVP reservation
==> = Aggregate RSVP reservation
Figure 1 : Aggregation of E2E Reservations
over Generic Aggregate RSVP Reservations
in PCN domains, based on [RFC4860]
In addition, in this document it is considered that the PCN-boundary
nodes are able to distinguish and process (1) RSVP SESSIONS for
generic aggregated sessions and their messages according to
[RFC4860], (2) e2e RSVP sessions and messages according to [RFC2205].
Furthermore, it is considered that the PCN-interior-nodes are not
able to distinguish neither RSVP generic aggregated sessions and
their associated messages [RFC4860], nor e2e RSVP sessions and their
associated messages [RFC2205].
Moreover, each Aggregator and Deaggregator (i.e., PCN-boundary-nodes)
MUST support policies to initiate and maintain for each combination
of the PCN-boundary-node and all other PCN-boundary-nodes of the same
PCN-domain one RSVP SESSION for generic aggregated reservations. Note
that RSVP SESSION for generic aggregated reservations can match to
one or more than one ingress-egress-aggregates. This can be
accomplished by using for the different ingress-egress-aggregates the
same combinations of ingress and egress identifiers, but with a
different PHB-ID value (see [RFC4860]). Depending on a policy the
Aggregator SHOULD be able to decide whether an e2e RSVP session can
be mapped into one ingress-egress-aggregate maintained by the
Aggregator (i.e., PCN-ingress-node).
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The RSVP SESSION object for generic aggregate reservations, maintains
the mapping and association between the PCN ingress-egress-aggregate
and the PCN-flows (e2e RSVP reservation session) that travel in one
direction between the specific pair of PCN-boundary-nodes specified
by the ingress-egress-aggregate. Note that in this document the PCN
ingress-egress-aggregate is identified by using the RSVP SESSION
object for generic aggregate reservation, see [RFC4860], by using the
following:
o) the IPv4 DestAddress, IPv6 DestAddress SHOULD be set to the IPv4
or IPv6 destination addresses, respectively, of the Deaggregator
(PCN-egress-node)
o) PHB-ID (Per Hop Behavior Identification Code) SHOULD be set equal
to PCN-compatible Diffserv codepoint(s).
o) Extended vDstPort SHOULD be set to the IPv4 or IPv6 destination
addresses, of the Aggregator (PCN-ingress-node)
2.1.1 PCN Marking and encoding and transport of pre-congestion
information
The method of PCN marking within the PCN domain is based on
[RFC5670]. In addition, the method of encoding and transport of pre-
congestion information is based [RFC5696]. The PHB-ID (Per Hop
Behavior Identification Code) used, SHOULD be set equal
to PCN-compatible Diffserv codepoint(s).
2.1.2. Traffic Classification Within The Aggregation Region
The PCN-traffic is marked using PCN-marking and is classified using
The PCN-BA (i.e., combination of the DSCP and ECN fields).
The PCN-traffic belonging to an PCN aggregated session can be
classified only at the PCN-boundary-nodes using the combination of
(1) PCN-BA (i.e., combination of the DSCP and ECN fields), (2) IP
addresses of the specific pair of PCN-boundary-nodes used by a
ingress-egress-aggregate.
The method of classification and traffic conditioning of PCN-traffic
and non-PCN traffic and PHB configuration is described in draft-ietf-
pcn-cl-edge-behaviour-09] and [draft-ietf-pcn-sm-edge-behaviour-06].
2.1.3. Deaggregator (PCN-egress-node) Determination
In this document it is considered that for the determination of the
Deaggregator, the same methods can be used as the ones described in
[RFC4860].
2.1.4. Mapping E2E Reservations Onto Aggregate Reservations
In this document it is considered that for the mapping of e2e
reservations onto aggregate reservations, the same methods can be
used as the ones described in [RFC4860], augmented by the following
rules:
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o) PCN-ingress-node MUST use one or more policies to estimate whether
an e2e RSVP reservation session associated with an e2e Path
message that arrives at the external interface of the PCN-ingress-
node can be mapped onto an existing RSVP generic aggregation
reservation state, i.e., PCN ingress-egress-aggregate.
2.1.5. Size of Aggregate Reservations
In this document it is considered that for the determination of the
size of the aggregate reservations, the same methods can be used as
the ones described in [RFC4860].
2.1.6. E2E Path ADSPEC update
In this document it is considered that for the update of the e2e Path
ADSPEC, the same methods can be used as the ones described in
[RFC4860].
2.1.7. Intra-domain Routes
The PCN-interior-nodes are neither maintaining e2e RSVP nor RSVP
generic aggregation states and reservations. Therefore, intra-domain
route changes will not affect intra-domain reservations since such
reservations are not maintained by the PCN-interior-nodes.
2.1.8. Inter-domain Routes
In this document it is considered that for the solving the issues
caused by the inter-domain route changes, the same methods can be
used as the ones described in [RFC4860].
2.1.9. Reservations for Multicast Sessions
PCN does not consider reservations for multicast sessions.
2.1.10. Multi-level Aggregation
PCN does not consider multi-level aggregations within the PCN domain.
2.1.11. Reliability Issues
In this document it is considered that for solving possible
reliability issues, the same methods can be used as the ones
described in [RFC4860].
2.1.12. Message Integrity and Node Authentication
In this document it is considered that for message integrity and node
authentication, the same methods can be used as the ones described in
[RFC4860] and [RFC5559].
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3. Elements of Procedure
This section describes the procedures used to implement the
aggregated RSVP procedure over PCN.
3.1. Receipt of E2E Path Message By PCN-ingress-node (aggregating
router)
When the e2e RSVP message arrives at the exterior interface of the
aggregator, i.e., PCN-ingress-node, then standard RSVP generic
aggregation [RFC4860] procedures are used, augmented with the
following rules:
o) The e2e RSVP reservation session associated with an e2e Path
message that arrives at the external interface of the PCN-
ingress-node is mapped onto an existing RSVP generic aggregation
reservation state (i.e., PCN ingress-egress-aggregate).
o) If the timer t-recvFail expires for a given PCN-egress-node, the
Decision Point (i.e., PCN-ingress-node) SHOULD NOT
allow the e2e RSVP flow to be admitted to that ingress-egress-
aggregate. This procedure is defined in detail in:
[draft-ietf-pcn-cl-edge-behaviour-09] and
[draft-ietf-pcn-sm-edge-behaviour-06].
Depending on a local policy the Aggregator SHOULD decide
whether this situation is considered of being an error, or
whether the e2e reservation session SHOULD be mapped to another
ingress-egress-aggregate maintained by the same RSVP SESSION
for aggregated reservations.
If the Aggregator is not able to map the requesting e2e RSVP
session into another ingress-egress-aggregate, then the
Aggregator SHOULD NOT admit the e2e RSVP session and it SHOULD
generate an e2e PathErr message using standard e2e RSVP
procedures [RFC2205]. This e2e PathErr message is sent to the
originating sender of the e2e Path message.
o) If the timer t-recvFail does NOT expire for a given PCN-egress-
node, then:
*) If the PCN-admission state for the ingress-egress-
aggregate associated with the received e2e Path is "admit",
the Decision Point (i.e., PCN-ingress-node) SHOULD allow new
flows to be admitted to that aggregate. The e2e Path message
is then forwarded towards destination.
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*) If the PCN-admission-state for the same PCN aggregation
state is "block", the Aggregator using the same policy as
mentioned above SHOULD either map the incoming e2e RSVP
session to another ingress-egress-aggregate associated with
the same generic aggregated RSVP session, or the flow
SHOULD NOT be admitted and an e2e PathErr message SHOULD be
generated, using standard e2e RSVP procedures [RFC2205],
[RFC4495].
This e2e PathErr message is sent to the originating sender
of the e2e Path message, using standard e2e RSVP procedures
[RFC2205], [RFC4495]. A new error code "PCN-domain rejects
e2e reservation" MUST be augmented to the RSVP error codes
to inform the sender that a PCN domains rejects the e2e
reservation request.
The way of how the PCN-admission-state is maintained is specified in
[draft-ietf-pcn-cl-edge-behaviour-09] and
[draft-ietf-pcn-sm-edge-behaviour-06].
3.2. Handling Of E2E Path Message By Interior Routers
The e2e Path messages traverse zero or more PCN-interior-nodes. The
PCN-interior-nodes receive the e2e Path message on an interior
interface and forward it on another interior interface. The e2e Path
messages are simply forwarded as normal IP datagrams.
3.3. Receipt of E2E Path Message By PCN-egress-node (deaggregating
router)
When receiving the e2e Path message the PCN-egress-node
(deaggregating router) performs main regular [RFC4860] procedures,
augmented with the following rules, see also [draft-lefaucheur-rsvp-
ecn-01]:
o) The PCN-egress-node MUST NOT perform the RSVP-TTL vs IP TTL-
check and MUST NOT update the ADspec Break bit. This is because
the whole PCN-domain is effectively handled by e2e RSVP as a
virtual link on which integrated service is indeed supported
(and admission control performed) so that the Break bit MUST
NOT be set.
The PCN-egress-nodes forwards the e2e Path message towards the
receiver.
3.4. Initiation of new Aggregate Path Message By PCN-ingress node
(Aggregating Router)
In this document it is considered that for the initiation of the new
RSVP aggregated Path message by the PCN-ingress-node (Aggregation
Router), the same methods can be used as the ones described in
[RFC4860].
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3.5. Handling Of new Aggregate Path Message By Interior Routers
The Aggregate Path messages traverse zero or more PCN-interior-nodes.
The PCN-interior-nodes receive the e2e Path message on an interior
interface and forward it on another interior interface. The
Aggregated Path messages are simply forwarded as normal IP datagrams.
3.6. Handling of E2E Resv Message by Deaggregating Router
When the e2e Resv message arrives at the exterior interface of the
Deaggregating router, i.e., PCN-egress-node, then standard RSVP
aggregation [RFC4860] procedures are used.
3.7. Handling Of E2E Resv Message By Interior Routers
The e2e Resv messages traverse zero or more PCN-interior-nodes. The
PCN-interior-nodes receive the e2e Resv message on an interior
interface and forward it on another interior interface. The e2e Resv
messages are simply forwarded as normal IP datagrams.
3.8. Initiation of New Aggregate Resv Message By Deaggregating Router
In this document it is considered that for the initiation of the new
RSVP aggregated Resv message by the PCN-ingress-node (Aggregation
Router), the same methods can be used as the ones described in
[RFC4860] augmented with the following rules:
o) At the end of each t-meas measurement interval, or less
frequently if "optional report suppression" is activated, see
[draft-ietf-pcn-cl-edge-behaviour-09], and
[draft-ietf-pcn-sm-edge-behaviour-06], the PCN-egress-node MUST
include the new PCN object that will be sent to the associated
Decision Point (i.e., PCN-ingress-node).
The PCN object is specified in this document and is used to
report of the data measured by the PCN-egress-node, for a
particular ingress-egress-aggregate, see [draft-ietf-pcn-cl-
edge-behaviour-09], and [draft-ietf-pcn-sm-edge-behaviour-06].
The address of the PCN-ingress-node is the one specified in the
same ingress-egress-aggregate.
3.9. Handling of Aggregate Resv Message by Interior Routers
The Aggregated Resv messages traverse zero or more PCN-interior-
nodes. The PCN-interior-nodes receive the Aggregated Resv message on
an interior interface and forward it on another interior interface.
The Aggregated Resv messages are simply forwarded as normal IP
datagrams.
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3.10. Handling of E2E Resv Message by Aggregating Router
When the e2e Resv message arrives at the interior interface of the
Aggregating router, i.e., PCN-ingress-node, then standard RSVP
aggregation [RFC4860] procedures are used.
3.11. Handling of Aggregated Resv Message by Aggregating Router
When the Aggregated Resv message arrives at the interior interface of
the Aggregating router, i.e., PCN-ingress-node, then standard RSVP
aggregation [RFC4860] procedures are used, augmented with the
following rules:
o) the Decision Point (i.e., the PCN-ingress-node) SHOULD use the
information carried by the PCN object as specified in
[draft-ietf-pcn-cl-edge-behaviour-09],
[draft-ietf-pcn-sm-edge-behaviour-06].
When the Aggregator (i.e., PCN-ingress-node) needs to terminate
an amount of traffic associated to one ingress-egress-aggregate
(see bullet 2 in Section 3.3.2 of [draft-ietf-pcn-cl-edge-
behaviour-09] and [draft-ietf-pcn-sm-edge-behaviour-06]), then
the following procedure is followed. Based on a local policy,
the Aggregator SHOULD select one of the following options:
o) for the same ingress-egress-aggregate, select a number of e2e
RSVP sessions to be terminated in order to decrease the
total incoming amount of bandwidth associated with one
ingress-egress-aggregate by the amount of traffic to be
terminated, see above. In this situation the same mechanisms
for terminating an e2e RSVP flow can be followed as specified
in [RFC4495].
o) for the same ingress-egress-aggregate, select a number of e2e
RSVP sessions to be terminated or to reduce their reserved
bandwidth in order to decrease the total incoming amount of
bandwidth associated with one ingress-egress-aggregate by the
amount of traffic to be terminated, see above. In this
situation the same mechanisms for terminating an e2e RSVP
flow or reducing bandwidth associated with an e2e RSVP
flow can be followed as specified in [RFC4495].
3.12. Removal of E2E Reservation
In this document it is considered that for the removal of e2e
reservations, the same methods can be used as the ones described in
[RFC4860] and [RFC4495].
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3.13. Removal of Aggregate Reservation
In this document it is considered that for the removal of aggregated
reservations, the same methods can be used as the ones described in
[RFC4860].
3.14. Handling of Data On Reserved E2E Flow by Aggregating Router
The handling of data on the reserved e2e Flow by Aggregating Router
is using the procedures described in [RFC4860] augmented with:
o) Regarding, PCN marking and traffic classification the procedures
defined in Section 2.1.1 and 2.1.3 of this document are used.
3.15. Procedures for Multicast Sessions
In this document no multicast sessions are considered.
4. Protocol Elements
The protocol elements in this document are using the protocol
Elements defined in [RFC4860], augmented with the following rules:
o) A PCN-egress-node (i.e., deaggregator) SHOULD send periodically
and at the end of each t-meas measurement interval, or less
frequently if "optional report suppression" is activated, an
(refresh) aggregated RSVP message to the PCN-ingress-node (i.e.
aggregator).
o) the DSCP value included in the SESSION object, SHOULD be set equal
to a PCN-compatible Diffserv codepoint.
o) An aggregated Resv message MUST carry a PCN object to report
the data measured by an PCN-egress-node (i.e., Deaggregator).
4.1 PCN object
The PCN object reports data measured by an PCN-egress-node.
PCN objects are defined for different PCN edge behavior drafts. This
document defines several types of PCN objects.
o) Single Marking (SM) PCN object, when IPv4 addresses are used:
Class = PCN
C-Type = RSVP-AGGREGATE-IPv4-PCN-SM
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+-------------+-------------+-------------+-------------+
| IPv4 PCN-ingress-node Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| IPv4 PCN-egress-node Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| Congestion-Level-Estimate |
+-------------+-------------+-------------+-------------+
| rate of not marked PCN-traffic (NM-rate) |
+-------------+-------------+-------------+-------------+
| rate of PCN-marked PCN-traffic (PM-rate) |
+-------------+-------------+-------------+-------------+
o) Single Marking (SM) PCN object, when IPv6 addresses are used:
Class = PCN
C-Type = RSVP-AGGREGATE-IPv6-PCN-SM
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ IPv6 PCN-ingress-node Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ IPv6 PCN-egress-node Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| Congestion-Level-Estimate |
+-------------+-------------+-------------+-------------+
| rate of not marked PCN-traffic (NM-rate) |
+-------------+-------------+-------------+-------------+
| rate of PCN-marked PCN-traffic (PM-rate) |
+-------------+-------------+-------------+-------------+
o) Controlled (CL) PCN object, IPv4 addresses are used:
Class = PCN
C-Type = RSVP-AGGREGATE-IPv4-PCN-CL
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+-------------+-------------+-------------+-------------+
| IPv4 PCN-ingress-node Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| IPv4 PCN-egress-node Address (4 bytes) |
+-------------+-------------+-------------+-------------+
| Congestion-Level-Estimate |
+-------------+-------------+-------------+-------------+
| rate of not marked PCN-traffic (NM-rate) |
+-------------+-------------+-------------+-------------+
| rate of threshold-marked PCN-traffic (ThM-rate) |
+-------------+-------------+-------------+-------------+
| rate of excess-traffic-marked PCN-traffic (ETM-rate) |
+-------------+-------------+-------------+-------------+
o) Controlled (CL) PCN object, IPv6 addresses are used:
Class = PCN
C-Type = RSVP-AGGREGATE-IPv6-PCN-CL
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ IPv6 PCN-ingress-node Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| |
+ +
| |
+ IPv6 PCN-egress-node Address (16 bytes) +
| |
+ +
| |
+-------------+-------------+-------------+-------------+
| Congestion-Level-Estimate |
+-------------+-------------+-------------+-------------+
| rate of not marked PCN-traffic (NM-rate) |
+-------------+-------------+-------------+-------------+
| rate of threshold-marked PCN-traffic (ThM-rate) |
+-------------+-------------+-------------+-------------+
| rate of excess-traffic-marked PCN-traffic (ETM-rate) |
+-------------+-------------+-------------+-------------+
The fields carried by the PCN object are specified in
[draft-ietf-pcn-signaling-requirements-06.txt], [draft-ietf-pcn-cl-
edge-behaviour-09] and [draft-ietf-pcn-sm-edge-behaviour-06]:
o the IPv4 or IPv6 address of the PCN-ingress-node and the the IPv4
or IPv6 address of the PCN-egress-node; together they specify the
ingress-egress-aggregate to which the report refers;
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o rate of not-marked PCN-traffic (NM-rate) in octets/second; its
format is a 32-bit IEEE floating point number;
o rate of PCN-marked traffic (PM-rate) in octets/second; its format
is a 32-bit IEEE floating point number;
o congestion-level-estimate, which is a number between zero and
one; its format is a 32-bit IEEE floating point number;
o rate of threshold-marked PCN traffic (ThM-rate) in
octets/second; its format is a 32-bit IEEE floating point number;
o rate of excess-traffic-marked traffic (ETM-rate) in
octets/second; its format is a 32-bit IEEE floating point number;
5. Security Considerations
The same security considerations specified in [RFC4860] and [RFC5559]
apply also to this document.
6. IANA Considerations
This document makes the following requests to the IANA:
o allocate a new Object Class (PCN Object), see Section 4.1.
o allocate a "PCN-domain rejects e2e reservation" Error Code that
may appear only in e2e PathErr messages, see Section 3.1.
Error Value for "PCN-domain rejects e2e reservation "= To be
allocated by IANA
7. Acknowledgments
We would like to thank the authors of [draft-lefaucheur-rsvp-ecn-
01.txt], since some ideas used in this document are based on the work
initiated in [draft-lefaucheur-rsvp-ecn-01.txt]. Moreover, we would
like to thank Tom Taylor, Francois Le Faucheur and James Polk for the
comments provided on the 00 version of this draft.
8. Normative References
[draft-ietf-pcn-cl-edge-behaviour-09] T. Taylor, A, Charny, F. Huang,
G. Karagiannis, M. Menth, "PCN Boundary Node Behaviour for the
Controlled Load (CL) Mode of Operation (Work in progress)", June
2011.
[draft-ietf-pcn-sm-edge-behaviour-06] A. Charny, J. Zhang,
G. Karagiannis, M. Menth, T. Taylor, "PCN Boundary Node Behaviour
for the Single Marking (SM) Mode of Operation (Work in progress)",
June 2011.
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[draft-ietf-pcn-signaling-requirements-06] G. Karagiannis, T. Taylor,
K. Chan, M. Menth, P. Eardley, " Requirements for Signaling of (Pre-)
Congestion Information in a DiffServ Domain(Work in progress)", July
2011.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2205] Braden, R., ed., et al., "Resource ReSerVation Protocol
(RSVP)- Functional Specification", RFC 2205, September 1997.
[RFC3140] Black, D., Brim, S., Carpenter, B., and F. Le
Faucheur, "Per Hop Behavior Identification Codes",
RFC 3140, June 2001.
[RFC3175] Baker, F., Iturralde, C., Le Faucheur, F., and B. Davie,
"Aggregation of RSVP for IPv4 and IPv6 Reservations", RFC 3175,
September 2001.
[RFC4495] Polk, J. and S. Dhesikan, "A Resource Reservation
Protocol (RSVP) Extension for the Reduction of
Bandwidth of a Reservation Flow", RFC 4495, May 2006.
[RFC4860] F. Le Faucheur, B. Davie, P. Bose, C. Christou, M.
Davenport, "Generic Aggregate Resource ReSerVation Protocol (RSVP)
Reservations", RFC4860, May 2007.
[RFC5670] Eardley, P., "Metering and Marking Behaviour of PCN-Nodes",
RFC 5670, November 2009.
[RFC5696] Moncaster, T., Briscoe, B., and M. Menth, "Baseline
Encoding and Transport of Pre-Congestion Information", RFC 5696,
November 2009.
9. Informative References
[draft-lefaucheur-rsvp-ecn-01.txt] Le Faucheur, F., Charny, A.,
Briscoe, B., Eardley, P., Chan, K., and J. Babiarz, "RSVP Extensions
for Admission Control over Diffserv using Pre-congestion
Notification (PCN) (Work in progress)", June 2006.
[RFC1633] Braden, R., Clark, D., and S. Shenker, "Integrated
Services in the Internet Architecture: an Overview", RFC 1633, June
1994.
[RFC2211] J. Wroclawski, Specification of the Controlled-Load Network
Element Service, September 1997
[RFC2212] S. Shenker et al., Specification of Guaranteed Quality of
Service, September 1997
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[RFC2474] Nichols, K., Blake, S., Baker, F., and D. Black,
"Definition of the Differentiated Services Field (DS Field) in the
IPv4 and IPv6 Headers", RFC 2474, December 1998.
[RFC2475] Blake, S., Black, D., Carlson, M., Davies, E., Wang, Z. and
W. Weiss, "A framework for Differentiated Services", RFC 2475,
December 1998.
[RFC2998] Bernet, Y., Yavatkar, R., Ford, P., Baker, F., Zhang, L.,
Speer, M., Braden, R., Davie, B., Wroclawski, J. and E. Felstaine, "A
Framework for Integrated Services Operation Over DiffServ Networks",
RFC 2998, November 2000.
[RFC5559] Eardley, P., "Pre-Congestion Notification (PCN)
Architecture", RFC 5559, June 2009.
10. Authors' Address
Georgios Karagiannis
University of Twente
P.O. Box 217
7500 AE Enschede,
The Netherlands
EMail: g.karagiannis@utwente.nl
Anurag Bhargava
Cisco Systems, Inc.
USA
Email: anuragb@cisco.com
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