Connections and Accesses for Hierarchical PCE
draft-chen-pce-h-connect-access-01
The information below is for an old version of the document.
| Document | Type |
This is an older version of an Internet-Draft whose latest revision state is "Active".
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|---|---|---|---|
| Authors | Huaimo Chen , Mehmet Toy , Lei Liu , Zhenqiang Li | ||
| Last updated | 2016-10-31 | ||
| RFC stream | (None) | ||
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| Additional resources | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
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| Send notices to | (None) |
draft-chen-pce-h-connect-access-01
1. Introduction
A hierarchical PCE architecture is described in RFC 6805, in which a
parent PCE maintains a domain topology containing its child domains
(seen as vertices in the topology) and the connections among the
domains.
For a domain for which a child PCE is responsible, connections
attached to the domain may comprise inter-domain links and Area
Border Routers (ABRs). For a parent PCE to have the domain topology,
each of its child PCEs needs to advertise its connections to the
parent PCE.
In addition to the connections attached to the domain, there may be
some access points in the domain, which are the addresses in the
domain to be accessible outside of the domain. For example, an
address of a server in the domain that provides a number of services
to users outside of the domain is an access point.
This document presents extensions to the Path Computation Element
Communication Protocol (PCEP) for a child PCE to advertise the
information about its connections and access points and for a parent
PCE to build and maintain the domain topology as well as access
points. The extensions may reduce configurations, thus simplify
operations on a PCE system.
2. Terminology
The following terminology is used in this document.
ABR: Area Border Router. Router used to connect two IGP areas
(Areas in OSPF or levels in IS-IS).
ASBR: Autonomous System Border Router. Router used to connect
together ASes of the same or different service providers via one
or more inter-AS links.
TED: Traffic Engineering Database.
This document uses terminology defined in [RFC5440].
3. Conventions Used in This Document
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].
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4. Connections and Accesses
A connection is an inter-domain link between two domains in general.
An ABR is also a connection, which connects two special domains
called areas in a same Autonomous System (AS).
An access point in a domain is an address in the domain to be
accessible to the outside of the domain. An access point is simply
called an access.
4.1. Information on Inter-domain Link
An inter-domain link connects two domains in two different ASes.
Since there is no IGP running over an inter-domain link, we may not
obtain the information about the link generated by an IGP. We may
suppose that IP addresses are configured on inter-domain links.
For a point-to-point link connecting two ABSRs A and B in two
different domains, from A's point of view, the following information
about the link may be obtained:
1) Link Type: Point-to-point
2) Local IP address of the link
3) Remote IP address of the link
4) Traffic engineering metric of the link
5) Maximum bandwidth of the link
6) Maximum reservable bandwidth of the link
7) Unreserved bandwidth of the link
8) Administrative group of the link
Note that no link ID (i.e., the Router ID of the neighbor) may be
obtained since no IGP adjacency over the link is formed.
For a broadcast link connecting multiple ASBRs in a number of
domains, on each of the ASBRs X, the same information about the link
as above may be obtained except for the followings:
a) Link Type: Multi-access,
b) Local IP address with mask length, and
c) No Remote IP address.
In other words, the information about the broadcast link obtained by
ASBR X comprises a), b), 4), 5), 6), 7) and 8), but does not include
any remote IP address or link ID. Note that no link ID (i.e., the
interface address of the designated router for the link) may be
obtained since no IGP selects it.
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A parent PCE constructs an AS domain topology after receiving the
information about each of the inter-domain links described above from
its child PCEs plus the local node ID such as A's ID.
A PCE such as a child PCE can constructs a TED for the domain for
which the PCE is responsible after receiving the information
described above about each of the links attached to the nodes in the
domain from the PCCs running on the nodes without running IGP.
RFC 5392 and RFC 5316 describe the distributions of inter-domain
links in OSPF and IS-IS respectively. For each inter-domain link,
its neighboring AS number and neighboring ASBR Identity (TE Router
ID) need to be configured in IGP (OSPF or IS-IS).
In addition, an IGP adjacency between a network node running IGP and
a PCE running IGP as a component needs to be configured and fully
established if we want the PCE to obtain the inter-domain link
information from IGP.
These configurations and IGP adjacency establishment are not needed
if the extensions in this draft are used.
RFC 7752 (BGP-LS) describes the distributions of TE link state
information including inter-domain link state. A BGP peer between a
network node running BGP and a PCE running BGP as a component needs
to be configured and the peer relation must be established before the
PCE can obtain the inter-domain link information from BGP. However,
some networks may not run BGP.
4.2. Information on ABR
For an AS running IGP and containing multiple areas, an ABR connects
two or more areas. For each area connected to the ABR, the PCE as a
child responsible for the area sends its parent PCE the information
about the ABR, which indicates the identifier (ID) of the ABR.
A parent PCE has the information about each of its child PCEs, which
includes the domain such as the area for which the child PCE is
responsible. The parent PCE knows all the areas to which each ABR
connects after receiving the information on the ABR from each of its
child PCEs.
4.3. Information on Access Point
For an IP address in a domain to be accessible outside of the domain,
the PCE as a child responsible for the domain sends its parent PCE
the information about the address, which indicates the address.
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The parent PCE has all the access points (i.e., IP addresses) to be
accessible outside of all its child PCEs' domains after receiving the
information on the access points from each of its child PCEs.
5. Extensions to PCEP
This section describes the extensions to PCEP to distribute the
information about inter-domain links, ABRs and access points. The
information is sent from a child PCE to its parent PCE. A child PCE
is simply called a child and a parent PCE is called a parent in the
following sections.
5.1. Extension to Existing Message
An existing Notification message may be extended to advertise the
information about connections and access points. Alternatively, a
new message can be used (refer to Appendix A).
The following new Notification-type (NT) and Notification-value (NV)
of a NOTIFICATION object in a Notification message are defined:
o NT=8 (TBD): Connections and Accesses
* NV=1: Updates on Connections and Accesses. A NT=8 and NV=1
indicates that the child sends its parent updates on the
information about Connections and Accesses, and TLVs containing
the information are in the NOTIFICATION object. The format and
contents of the TLVs are described below.
* NV=2: Withdraw Connections and Accesses. A NT=8 and NV=2
indicates that the child asks its parent to remove Connections
and Accesses indicated by the TLVs in the object.
5.1.1. TLVs
Four TLVs are defined for the information on connections and
accesses. They are Inter-Domain link TLV, Router-ID TLV, Access IPv4
Prefix TLV and Access IPv6 Prefix TLV.
The format of the Inter-Domain link TLV is illustrated below. The
Type=tTBD1 indicates an Inter-Domain link TLV Type. The Length
indicates the size of the Inter-Domain Link Sub-TLVs.
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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 (tTBD1) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inter-Domain Link Sub-TLVs |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
An Inter-Domain link TLV describes a single inter-domain link. It
comprises a number of inter-domain link sub-TLVs for the information
described in section 4.1, which are the sub-TLVs defined in RFC 3630
or their equivalents except for the local IP address with mask length
defined below.
The format of the Router-ID TLV is shown below. The Type=tTBD2
indicates a Router-ID TLV Type. The Length indicates the size of the
ID and flags field.
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 (tTBD2) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|B|E|I| Flags | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| 32-bit/48-bit ID ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Flag B: Set to 1 indicating ABR (B is for Border)
Flag E: Set to 1 indicating ASBR (E is for External)
Flag I: Set to 1 indicating ID of local router (I is for ID)
Undefined flags MUST be set to zero. The ID indicates the ID of a
router. For a router running OSPF, the ID may be the 32-bit OSPF
router ID of the router. For a router running IS-IS, the ID may be
the 48-bit IS-IS router ID of the router. For a router not running
OSPF or IS-IS, the ID may be the 32-bit ID of the router configured.
The format of the Access IPv4 Prefix TLV is shown as follows. The
Type=tTBD3 indicates an Access IPv4 Address Prefix TLV Type. The
Length indicates the size of the IPv4 prefix and Prefix Length. The
Prefix Length indicates the length of the IPv4 prefix. The IPv4
Prefix indicates an access IPv4 address prefix.
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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 (tTBD3) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Length | IPv4 Prefix (variable) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format of the Access IPv6 Prefix TLV is illustrated below. The
Type=tTBD4 indicates an Access IPv6 Address Prefix TLV Type. The
Length indicates the size of the IPv6 prefix and Prefix Length. The
Prefix Length indicates the length of the IPv6 prefix. The IPv6
Prefix indicates an access IPv6 address prefix.
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 (tTBD4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Length | IPv6 Prefix (variable) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
5.1.2. Sub-TLVs
The format of the Sub-TLV for a local IPv4 address with mask length
is shown as follows. The Type=stTBD1 indicates a local IPv4 Address
with mask length. The Length indicates the size of the IPv4 address
and Mask Length. The IPv4 Address indicates the local IPv4 address
of a link. The Mask Length indicates the length of the IPv4 address
mask.
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 (stTBD1) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv4 Address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mask Length |
+-+-+-+-+-+-+-+-+
The format of the Sub-TLV for a local IPv6 address with mask length
is illustrated below. The Type=stTBD2 indicates a local IPv6 Address
with mask length. The Length indicates the size of the IPv6 address
and Mask Length. The IPv6 Address indicates the local IPv6 address
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of a link. The Mask Length indicates the length of the IPv6 address
mask.
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 (stTBD2) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IPv6 Address (16 bytes) |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Mask Length |
+-+-+-+-+-+-+-+-+
5.2. Procedures
5.2.1. Child Procedures
1. New or Changed Connections and Accesses
After a child discovers its parent, it sends the parent messages that
contain the information about the connections (i.e., inter-domain
links and ABRs) from its domain to its adjacent domains and the
access points in its domain.
When there are changes on the connections and the accesses of the
domain, the child sends its parent messages for the changed
connections and accesses.
For any new or changed inter-domain links, ABRs and access points in
the domain for which a child is responsible, the child sends its
parent messages containing the information about these links, ABRs
and access points with indication of Updates on Connections and
Accesses.
For example, for a new inter-domain point-to-point link from ASBR A
in a child's domain to ASBR B in another domain, the child may send
its parent a Notification message having a NOTIFICATION object with
NT=8 and NV=1 (indicating Updates on Connections and Accesses), which
contains a Router-ID TLV, followed by an Inter-domain link TLV. The
Router-ID TLV comprises the ID of ASBR A and flag E and I set to 1.
The Inter-domain link TLV comprises the Sub-TLVs for the information
on 1) to 8) described in section 4.1.
For multiple new or changed inter-domain links from ASBR A, the child
may send its parent a Notification message having a NOTIFICATION
object with NT=8 and NV=1, which contains a Router-ID TLV for the ID
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of ASBR A, followed by multiple Inter-domain link TLVs for the links
from ASBR A. If A is also an ABR, in addition to setting flag E and I
to 1, the child sets flag B to 1 in the Router-ID TLV. Thus this one
message contains the information about multiple inter-domains links
and an ABR.
In another example, for a new or changed inter-domain broadcast link
connected to ASBR X, an ABR Y and an access point 10.10.10.1/32 in a
child's domain, the child may send its parent a Notification message
having a NOTIFICATION object with NT=8 and NV=1, which contains a
Router-ID TLV for the ID of ASBR X, followed by an Inter-domain link
TLV for the link attached to ASBR X, another Router-ID TLV for the ID
of ABR Y with flag B set to 1, and an Access IPv4 Prefix TLV with
10.10.10.1 and Prefix Length = 32. The Inter-domain link TLV
comprises the Sub-TLVs for the information on a), b), 4), 5), 6), 7)
and 8) described in section 4.1.
For changes on the attributes (such as bandwidth) of an inter-domain
link, a threshold may be used to control the frequency of updates
that are sent from a child to its parent. At one extreme, the
threshold is set to let a child send its parent a update message for
any change on the attributes of an inter-domain link. At another
extreme, the threshold is set to make a child not to send its parent
any update message for any change on the attributes of an inter-
domain link. Typically, the threshold is set to allow a child to
send its parent a update message for a significant change on the
attributes of an inter-domain link.
2. Connections and Accesses Down
For any inter-domain links, ABRs and access points down in the domain
for which a child is responsible, the child sends its parent messages
containing the information about these links, ABRs and access points
with indication of Withdraw Connections and Accesses.
For example, for the inter-domain point-to-point link from ASBR A to
ASBR B down, the child may send its parent a Notification message
having a NOTIFICATION object with NT=8 and NV=2 (indicating Withdraw
Connections and Accesses), which contains a Router-ID TLV, followed
by an Inter-domain link TLV. The Router-ID TLV comprises the ID of
ASBR A and flag E and I set to 1. The Inter-domain link TLV
comprises the Sub-TLVs for the information on 1), 2) and 3) described
in section 4.1.
For multiple inter-domain links from ASBR A down, the child may send
its parent a Notification message having a NOTIFICATION object with
NT=8 and NV=2, which contains a Router-ID TLV for the ID of ASBR A,
followed by multiple Inter-domain link TLVs for the links from ASBR
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A. The TLV for a point-to-point link comprises the Sub-TLVs for the
information on 1), 2) and 3) described in section 4.1. The TLV for a
broadcast link comprises the Sub-TLVs for the information on a) and
b) described in section 4.1.
3. Child and Parent in Same Organization
If a child and its parent are in a same organization, the child may
send its parent the information inside its domain. For a parent,
after all its children in its organization send their parent the
information in their domains, connections and access points, the
parent can compute a path crossing these domains directly and
efficiently without sending any path computation request to its
children.
4. Child as a Parent
There are a number of ways in which a child as a parent abstracts or
summarizes the domain information it has to its parent.
One way is that the child sends its parent all the domain information
it has if the child and the parent are in a same organization. The
information includes the network topology inside a domain if the
child responsible for the domain is in the same organization. The
information contains the inter-domain links connecting the domains
that the child's children are responsible and the inter-domain links
connecting these domains to other adjacent domains.
In another way, the child abstracts each of the domains that its
children are responsible as a cloud (or say abstract node) and these
clouds are connected by the inter-domain links attached to the
domains. The child sends its parent all the inter-domain links
attached to any of the domains.
In a third way, the child abstracts all the domains that its children
are responsible as a cloud. This abstraction is described below in
details.
If a parent P1 is also a child of another parent P2, P1 as a child
sends its parent P2 a message containing the information about the
connections and access points. P1 as a parent has the connections
among its children's domains. But these connections are hidden from
its parent P2. P1 may have connections from its children's domains
to other domains. P1 as a child sends its parent P2 these
connections.
P1 as a parent has the access points in its children's domains to be
accessible outside of the domains. P1 as child may not send all of
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these to its parent P2. It sends its parent some of these access
points according to some local policies.
From P2's point of view, its child P1 is responsible for one domain,
which has some connections to its adjacent domains and some access
points to be accessible.
5.2.2. Parent Procedures
A parent stores the connections and accesses for each of its children
according to the messages for connections and accesses received. For
a message containing updates on connections and accesses, it updates
the connections and accesses accordingly. For a message containing
withdraw connections and accesses, it removes the connections and
accesses.
When a child is down, its parent removes the connections and accesses
of the child's domain.
After receiving the messages for connections and accesses from its
children, a parent builds and maintains a TED for the topology of its
children's domains, in which each of the domains is seen as a cloud
or an abstract node. The information inside each of the domains is
hidden from the parent. There are connections among the domains and
the access points in the domains to be accessible in the topology.
6. Security Considerations
The mechanism described in this document does not raise any new
security issues for the PCEP protocols.
7. IANA Considerations
This section specifies requests for IANA allocation.
8. Acknowledgement
The authors would like to thank Eric Wu and others for their valuable
comments on this draft.
9. References
9.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/
RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
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[RFC6805] King, D., Ed. and A. Farrel, Ed., "The Application of the
Path Computation Element Architecture to the Determination
of a Sequence of Domains in MPLS and GMPLS", RFC 6805,
DOI 10.17487/RFC6805, November 2012,
<http://www.rfc-editor.org/info/rfc6805>.
[RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
Element (PCE) Communication Protocol (PCEP)", RFC 5440,
DOI 10.17487/RFC5440, March 2009,
<http://www.rfc-editor.org/info/rfc5440>.
[RFC3630] Katz, D., Kompella, K., and D. Yeung, "Traffic Engineering
(TE) Extensions to OSPF Version 2", RFC 3630,
DOI 10.17487/RFC3630, September 2003,
<http://www.rfc-editor.org/info/rfc3630>.
9.2. Informative References
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, DOI 10.17487/RFC5305,
October 2008, <http://www.rfc-editor.org/info/rfc5305>.
[RFC5392] Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in
Support of Inter-Autonomous System (AS) MPLS and GMPLS
Traffic Engineering", RFC 5392, DOI 10.17487/RFC5392,
January 2009, <http://www.rfc-editor.org/info/rfc5392>.
[RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in
Support of Inter-Autonomous System (AS) MPLS and GMPLS
Traffic Engineering", RFC 5316, DOI 10.17487/RFC5316,
December 2008, <http://www.rfc-editor.org/info/rfc5316>.
[RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and
S. Ray, "North-Bound Distribution of Link-State and
Traffic Engineering (TE) Information Using BGP", RFC 7752,
DOI 10.17487/RFC7752, March 2016,
<http://www.rfc-editor.org/info/rfc7752>.
Appendix A. New Message
A new message may be defined to advertise the connections and
accesses from a child to its parent. The format of the message
containing Connections and Access points (AC for short) is as
follows:
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<AC Message> ::= <Common Header>
<NRP>
<Connection-List>
[<Access-Address-List>]
where:
<Connection-List> ::= <Connection>
[<Connection-List>]
<Connection> ::= [<Inter-Domain-Link> | <ABR>]
<Access-Address-List> ::= <Access-Address>
[<Access-Address-List>]
Where the value of the Message-Type in the Common Header indicates
the new message type. The exact value is to be assigned by IANA. A
new RP (NRP) object will be defined, which follows the Common Header.
A new flag W (Withdraw) in the NRP object is defined to indicate
whether the connections and access points are withdrawn. When flag W
is set to one, the parent removes the connections and accesses
contained in the message after receiving it from its child. When
flag W is set to zero, the parent adds/updates the connections and
accesses in the message after receiving it.
An alternative to flag W in the NRP object is a similar flag in each
CONNECTION and ACCESS object such as using one bit in Res flags for
flag W. For example, when the flag is set to one in the object, the
parent removes the connections and accesses in the object after
receiving it. When the flag is set to zero in the object, the parent
adds/updates the connections and accesses in the object after
receiving it.
In another option, one byte in a CONNECTION and ACCESS Object is
defined as flags field and one bit is used as flag W. The other
undefined bits in the flags field MUST be set to zero.
The objects in the new message are defined below.
A.1. CONNECTION and ACCESS Object
A new object, called CONNECTION and ACCESS Object (CA for short), is
defined. It has Object-Class ocTBD1. Four Object-Types are defined
under CA object:
o CA Inter-Domain Link: CA Object-Type is 1.
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o CA ABR: CA Object-Type is 2.
o CA Access IPv4 Prefix: CA Object-Type is 3.
o CA Access IPv6 Prefix: CA Object-Type is 4.
Each of these objects are described below.
The format of Inter-Domain Link object body is as follows:
Object-Class = ocTBD1 (Connection and Access)
Object-Type = 1 (CA Inter-Domain Link)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|W| Flags | Router-ID TLV |
+-+-+-+-+-+-+-+-+ +
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inter-Domain Link TLVs |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Router-ID TLV indicates an ASBR in the domain, which is a local
end of inter-domain links. Each of the Inter-Domain Link TLVs
describes an inter-domain link and comprises a number of inter-domain
link Sub-TLVs. Flag W=1 indicates withdraw the links. W=0 indicates
new or changed links.
The format of ABR object body is illustrated below:
Object-Class = ocTBD1 (Connection and Access)
Object-Type = 2 (CA ABR)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|W| Flags | Router-ID TLVs |
+-+-+-+-+-+-+-+-+ +
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Each of the Router-ID TLVs indicates an ABR in the domain. Flag W=1
indicates withdraw the ABRs. W=0 indicates new ABRs.
The format of Access IPv4 Prefix object body is as follows:
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Object-Class = ocTBD1 (Connection and Access)
Object-Type = 3 (CA Access IPv4 Prefix)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|W| Flags | Access IPv4 Prefix TLVs |
+-+-+-+-+-+-+-+-+ +
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Each of the Access IPv4 Prefix TLVs describes an access IPv4 address
prefix in the domain, which is accessible to outside of the domain.
Flag W=1 indicates withdraw the address prefixes. W=0 indicates new
address prefixes.
The format of Access IPv6 Prefix object body is shown below:
Object-Class = ocTBD1 (Connection and Access)
Object-Type = 4 (CA Access IPv6 Prefix)
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|W| Flags | Access IPv6 Prefix TLVs |
+-+-+-+-+-+-+-+-+ +
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Each of the Access IPv6 Prefix TLVs describes an access IPv6 address
prefix in the domain, which is accessible to outside. Flag W=1
indicates withdraw the prefixes. W=0 indicates new prefixes.
A.2. TLVs in CONNECTION and ACCESS Object
The format of the Router-ID TLV is illustrated below:
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 (tTBD1) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 32-bit/48-bit ID ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format of the Access IPv4 Prefix TLV is shown as follows:
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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 (tTBD2) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Length | IPv4 Prefix (variable) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format of the Access IPv6 Prefix TLV is illustrated below:
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 (tTBD3) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Length | IPv6 Prefix (variable) ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The format of the Inter-Domain link TLV is shown below:
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 (tTBD4) | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Inter-Domain Link Sub-TLVs |
~ ~
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The inter-domain link sub-TLVs are for the information on a link
described in section 4.1, which are the sub-TLVs defined in RFC 3630
or their equivalents except for local IP address with mask length.
Authors' Addresses
Huaimo Chen
Huawei Technologies
Boston, MA,
USA
EMail: Huaimo.chen@huawei.com
Chen, et al. Expires May 4, 2017 [Page 17]
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Mehmet Toy
USA
EMail: mtoy054@yahoo.com
Lei Liu
Fujitsu
USA
EMail: lliu@us.fujitsu.com
Zhenqiang Li
China Mobile
No.32 Xuanwumenxi Ave., Xicheng District
Beijing 100032
P.R. China
EMail: li_zhenqiang@hotmail.com
Chen, et al. Expires May 4, 2017 [Page 18]