draft-ietf-idr-ls-distribution-01.txt   draft-ietf-idr-ls-distribution-02.txt 
Inter-Domain Routing H. Gredler Inter-Domain Routing H. Gredler
Internet-Draft Juniper Networks, Inc. Internet-Draft Juniper Networks, Inc.
Intended status: Standards Track J. Medved Intended status: Standards Track J. Medved
Expires: April 25, 2013 S. Previdi Expires: August 28, 2013 S. Previdi
Cisco Systems, Inc. Cisco Systems, Inc.
A. Farrel A. Farrel
Juniper Networks, Inc. Juniper Networks, Inc.
S. Ray S. Ray
Cisco Systems, Inc. Cisco Systems, Inc.
October 22, 2012 February 24, 2013
North-Bound Distribution of Link-State and TE Information using BGP North-Bound Distribution of Link-State and TE Information using BGP
draft-ietf-idr-ls-distribution-01 draft-ietf-idr-ls-distribution-02
Abstract Abstract
In a number of environments, a component external to a network is In a number of environments, a component external to a network is
called upon to perform computations based on the network topology and called upon to perform computations based on the network topology and
current state of the connections within the network, including current state of the connections within the network, including
traffic engineering information. This is information typically traffic engineering information. This is information typically
distributed by IGP routing protocols within the network distributed by IGP routing protocols within the network
This document describes a mechanism by which links state and traffic This document describes a mechanism by which links state and traffic
skipping to change at page 2, line 10 skipping to change at page 2, line 10
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 25, 2013. This Internet-Draft will expire on August 28, 2013.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
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the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Motivation and Applicability . . . . . . . . . . . . . . . . . 5 2. Motivation and Applicability . . . . . . . . . . . . . . . . . 5
2.1. MPLS-TE with PCE . . . . . . . . . . . . . . . . . . . . . 5 2.1. MPLS-TE with PCE . . . . . . . . . . . . . . . . . . . . . 5
2.2. ALTO Server Network API . . . . . . . . . . . . . . . . . 7 2.2. ALTO Server Network API . . . . . . . . . . . . . . . . . 7
3. Carrying Link State Information in BGP . . . . . . . . . . . . 8 3. Carrying Link State Information in BGP . . . . . . . . . . . . 8
3.1. TLV Format . . . . . . . . . . . . . . . . . . . . . . . . 8 3.1. TLV Format . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2. The Link State NLRI . . . . . . . . . . . . . . . . . . . 9 3.2. The Link State NLRI . . . . . . . . . . . . . . . . . . . 9
3.2.1. Node Descriptors . . . . . . . . . . . . . . . . . . . 11 3.2.1. Identifier TLV . . . . . . . . . . . . . . . . . . . . 12
3.2.2. Link Descriptors . . . . . . . . . . . . . . . . . . . 15 3.2.2. Node Descriptors . . . . . . . . . . . . . . . . . . . 14
3.2.3. The Prefix NLRI . . . . . . . . . . . . . . . . . . . 16 3.2.3. Link Descriptors . . . . . . . . . . . . . . . . . . . 22
3.3. The LINK_STATE Attribute . . . . . . . . . . . . . . . . . 16 3.2.4. Prefix Descriptors . . . . . . . . . . . . . . . . . . 23
3.3.1. Link Attribute TLVs . . . . . . . . . . . . . . . . . 16 3.3. The LINK_STATE Attribute . . . . . . . . . . . . . . . . . 23
3.3.2. Node Attribute TLVs . . . . . . . . . . . . . . . . . 20 3.3.1. Link Attribute TLVs . . . . . . . . . . . . . . . . . 24
3.3.3. Prefix Attributes TLVs . . . . . . . . . . . . . . . . 23 3.3.2. Node Attribute TLVs . . . . . . . . . . . . . . . . . 27
3.4. BGP Next Hop Information . . . . . . . . . . . . . . . . . 27 3.3.3. Prefix Attributes TLVs . . . . . . . . . . . . . . . . 29
3.5. Inter-AS Links . . . . . . . . . . . . . . . . . . . . . . 27 3.4. BGP Next Hop Information . . . . . . . . . . . . . . . . . 33
4. Link to Path Aggregation . . . . . . . . . . . . . . . . . . . 27 3.5. Inter-AS Links . . . . . . . . . . . . . . . . . . . . . . 33
4.1. Example: No Link Aggregation . . . . . . . . . . . . . . . 27 4. Link to Path Aggregation . . . . . . . . . . . . . . . . . . . 33
4.2. Example: ASBR to ASBR Path Aggregation . . . . . . . . . . 28 4.1. Example: No Link Aggregation . . . . . . . . . . . . . . . 34
4.3. Example: Multi-AS Path Aggregation . . . . . . . . . . . . 28 4.2. Example: ASBR to ASBR Path Aggregation . . . . . . . . . . 34
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 29 4.3. Example: Multi-AS Path Aggregation . . . . . . . . . . . . 35
6. Manageability Considerations . . . . . . . . . . . . . . . . . 29 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35
6.1. Operational Considerations . . . . . . . . . . . . . . . . 29 6. Manageability Considerations . . . . . . . . . . . . . . . . . 35
6.1.1. Operations . . . . . . . . . . . . . . . . . . . . . . 29 6.1. Operational Considerations . . . . . . . . . . . . . . . . 35
6.1.2. Installation and Initial Setup . . . . . . . . . . . . 30 6.1.1. Operations . . . . . . . . . . . . . . . . . . . . . . 36
6.1.3. Migration Path . . . . . . . . . . . . . . . . . . . . 30 6.1.2. Installation and Initial Setup . . . . . . . . . . . . 36
6.1.3. Migration Path . . . . . . . . . . . . . . . . . . . . 36
6.1.4. Requirements on Other Protocols and Functional 6.1.4. Requirements on Other Protocols and Functional
Components . . . . . . . . . . . . . . . . . . . . . . 30 Components . . . . . . . . . . . . . . . . . . . . . . 36
6.1.5. Impact on Network Operation . . . . . . . . . . . . . 30 6.1.5. Impact on Network Operation . . . . . . . . . . . . . 36
6.1.6. Verifying Correct Operation . . . . . . . . . . . . . 30 6.1.6. Verifying Correct Operation . . . . . . . . . . . . . 37
6.2. Management Considerations . . . . . . . . . . . . . . . . 31 6.2. Management Considerations . . . . . . . . . . . . . . . . 37
6.2.1. Management Information . . . . . . . . . . . . . . . . 31 6.2.1. Management Information . . . . . . . . . . . . . . . . 37
6.2.2. Fault Management . . . . . . . . . . . . . . . . . . . 31 6.2.2. Fault Management . . . . . . . . . . . . . . . . . . . 37
6.2.3. Configuration Management . . . . . . . . . . . . . . . 31 6.2.3. Configuration Management . . . . . . . . . . . . . . . 37
6.2.4. Accounting Management . . . . . . . . . . . . . . . . 31 6.2.4. Accounting Management . . . . . . . . . . . . . . . . 37
6.2.5. Performance Management . . . . . . . . . . . . . . . . 31 6.2.5. Performance Management . . . . . . . . . . . . . . . . 37
6.2.6. Security Management . . . . . . . . . . . . . . . . . 32 6.2.6. Security Management . . . . . . . . . . . . . . . . . 38
7. Security Considerations . . . . . . . . . . . . . . . . . . . 32 7. TLV/SubTLV Code Points Summary . . . . . . . . . . . . . . . . 38
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 32 8. Security Considerations . . . . . . . . . . . . . . . . . . . 40
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 32 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 40
9.1. Normative References . . . . . . . . . . . . . . . . . . . 32 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 40
9.2. Informative References . . . . . . . . . . . . . . . . . . 34 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 34 11.1. Normative References . . . . . . . . . . . . . . . . . . . 40
11.2. Informative References . . . . . . . . . . . . . . . . . . 42
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 43
1. Introduction 1. Introduction
The contents of a Link State Database (LSDB) or a Traffic Engineering The contents of a Link State Database (LSDB) or a Traffic Engineering
Database (TED) has the scope of an IGP area. Some applications, such Database (TED) has the scope of an IGP area. Some applications, such
as end-to-end Traffic Engineering (TE), would benefit from visibility as end-to-end Traffic Engineering (TE), would benefit from visibility
outside one area or Autonomous System (AS) in order to make better outside one area or Autonomous System (AS) in order to make better
decisions. decisions.
The IETF has defined the Path Computation Element (PCE) [RFC4655] as The IETF has defined the Path Computation Element (PCE) [RFC4655] as
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to be collected from the IGP within the network, filtered according to be collected from the IGP within the network, filtered according
to configurable policy, and distributed to the PCE as necessary. to configurable policy, and distributed to the PCE as necessary.
2.2. ALTO Server Network API 2.2. ALTO Server Network API
An ALTO Server [RFC5693] is an entity that generates an abstracted An ALTO Server [RFC5693] is an entity that generates an abstracted
network topology and provides it to network-aware applications over a network topology and provides it to network-aware applications over a
web service based API. Example applications are p2p clients or web service based API. Example applications are p2p clients or
trackers, or CDNs. The abstracted network topology comes in the form trackers, or CDNs. The abstracted network topology comes in the form
of two maps: a Network Map that specifies allocation of prefixes to of two maps: a Network Map that specifies allocation of prefixes to
PIDs, and a Cost Map that specifies the cost between PIDs listed in Partition Identifiers (PIDs), and a Cost Map that specifies the cost
the Network Map. For more details, see [I-D.ietf-alto-protocol]. between PIDs listed in the Network Map. For more details, see
[I-D.ietf-alto-protocol].
ALTO abstract network topologies can be auto-generated from the ALTO abstract network topologies can be auto-generated from the
physical topology of the underlying network. The generation would physical topology of the underlying network. The generation would
typically be based on policies and rules set by the operator. Both typically be based on policies and rules set by the operator. Both
prefix and TE data are required: prefix data is required to generate prefix and TE data are required: prefix data is required to generate
ALTO Network Maps, TE (topology) data is required to generate ALTO ALTO Network Maps, TE (topology) data is required to generate ALTO
Cost Maps. Prefix data is carried and originated in BGP, TE data is Cost Maps. Prefix data is carried and originated in BGP, TE data is
originated and carried in an IGP. The mechanism defined in this originated and carried in an IGP. The mechanism defined in this
document provides a single interface through which an ALTO Server can document provides a single interface through which an ALTO Server can
retrieve all the necessary prefix and network topology data from the retrieve all the necessary prefix and network topology data from the
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+--------+ | | | | | +--------+ | | | | |
| +--------+ +---------+ | +--------+ +---------+
+--------+ | +--------+ |
| Client |<--+ | Client |<--+
+--------+ +--------+
Figure 3: ALTO Server using network topology information Figure 3: ALTO Server using network topology information
3. Carrying Link State Information in BGP 3. Carrying Link State Information in BGP
Two parts: a new BGP NLRI that describes links and nodes comprising This specification contains two parts: definition of a new BGP NLRI
IGP link state information, and a new BGP path attribute that carries that describes links, nodes and prefixes comprising IGP link state
link and node properties and attributes, such as the link metric or information, and definition of a new BGP path attribute that carries
node properties. link, node and prefix properties and attributes, such as the link and
prefix metric or node properties.
3.1. TLV Format 3.1. TLV Format
Information in the new link state NLRIs and attributes is encoded in Information in the new link state NLRIs and attributes is encoded in
Type/Length/Value triplets. The TLV format is shown in Figure 4. Type/Length/Value triplets. The TLV format is shown in Figure 4.
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| Value (variable) | | Value (variable) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: TLV format Figure 4: TLV format
The Length field defines the length of the value portion in octets The Length field defines the length of the value portion in octets
(thus a TLV with no value portion would have a length of zero). The (thus a TLV with no value portion would have a length of zero). The
TLV is not padded to four-octet alignment; Unrecognized types are TLV is not padded to four-octet alignment. Unrecognized types are
ignored. ignored.
3.2. The Link State NLRI 3.2. The Link State NLRI
The MP_REACH and MP_UNREACH attributes are BGP's containers for The MP_REACH and MP_UNREACH attributes are BGP's containers for
carrying opaque information. Each Link State NLRI describes either a carrying opaque information. Each Link State NLRI describes either a
single node or link. node, a link or a prefix.
All link, node and prefix information SHALL be encoded using a TBD All link, node and prefix information SHALL be encoded using a TBD
AFI / TBD SAFI header into those attributes. AFI / TBD SAFI header into those attributes.
In order for two BGP speakers to exchange Link-State NLRI, they MUST In order for two BGP speakers to exchange Link-State NLRI, they MUST
use BGP Capabilities Advertisement to ensure that they both are use BGP Capabilities Advertisement to ensure that they both are
capable of properly processing such NLRI. This is done as specified capable of properly processing such NLRI. This is done as specified
in [RFC4760], by using capability code 1 (multi-protocol BGP), with in [RFC4760], by using capability code 1 (multi-protocol BGP), with
an AFI/SAFI TBD. an AFI/SAFI TBD.
skipping to change at page 9, line 32 skipping to change at page 9, line 34
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NLRI Type | Total NLRI Length | | NLRI Type | Total NLRI Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| Link-State NLRI (variable) | | Link-State NLRI (variable) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 5: Link State SAFI 1 NLRI Format Figure 5: Link State SAFI (TBD) NLRI Format
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NLRI Type | Total NLRI Length | | NLRI Type | Total NLRI Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
+ Route Distinguisher + + Route Distinguisher +
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| Link-State NLRI (variable) | | Link-State NLRI (variable) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 6: Link State SAFI 128 NLRI Format Figure 6: Link State SAFI 128 NLRI Format
The 'Total NLRI Length' field contains the cumulative length of all The 'Total NLRI Length' field contains the cumulative length of rest
the TLVs in the NLRI. For VPN applications it also includes the of the NLRI not including the NLRI Type field or itself. For VPN
length of the Route Distinguisher. applications it also includes the length of the Route Distinguisher.
The 'NLRI Type' field can contain one of the following values: The 'NLRI Type' field can contain one of the following values:
Type = 1: Link NLRI, contains link descriptors and link attributes Type = 1: Link NLRI, contains link descriptors and link attributes
Type = 2: Node NLRI, contains node attributes Type = 2: Node NLRI, contains node attributes
Type = 3: IPv4 Topology Prefix NLRI Type = 3: IPv4 Topology Prefix NLRI
Type = 4: IPv6 Topology Prefix NLRI Type = 4: IPv6 Topology Prefix NLRI
The Link NLRI (NLRI Type = 1) is shown in the following figure. The Link NLRI (NLRI Type = 1) is shown in the following figure.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protocol-ID | Reserved | Instance Identifier | | Protocol-ID | Reserved | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| Identifier (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Node Descriptors (variable) | | Local Node Descriptors (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Remote Node Descriptors (variable) | | Remote Node Descriptors (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Link Descriptors (variable) | | Link Descriptors (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: The Link NLRI format Figure 7: The Link NLRI format
The Node NLRI (NLRI Type = 2) is shown in the following figure. The Node NLRI (NLRI Type = 2) is shown in the following figure.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protocol-ID | Reserved | Instance Identifier | | Protocol-ID | Reserved | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| Identifier (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Local Node Descriptors (variable) | | Local Node Descriptors (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: The Node NLRI format Figure 8: The Node NLRI format
The IPv4 and IPv6 Prefix NLRIs (NLRI Type = 3 and Type = 4) use the The IPv4 and IPv6 Prefix NLRIs (NLRI Type = 3 and Type = 4) use the
same format as shown in the following figure. same format as shown in the following figure.
0 1 2 3 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 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protocol-ID | Reserved | Instance Identifier | | Protocol-ID | Reserved | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +
| Identifier (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Node Descriptor | | Local Node Descriptor (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix NLRI (variable) | | Reachability information (variable; one or more prefixes) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 9: The IPv4/IPv6 Topology Prefix NLRI format Figure 9: The IPv4/IPv6 Topology Prefix NLRI format
The 'Protocol-ID' field can contain one of the following values: The 'Protocol-ID' field can contain one of the following values:
Protocol-ID = 0: Unknown, The source of NLRI information could not Protocol-ID = 0: Unknown, The source of NLRI information could not
be determined be determined
Protocol-ID: IS-IS Level 1, The NLRI information has been sourced Protocol-ID = 1: IS-IS Level 1, The NLRI information has been
by IS-IS Level 1 sourced by IS-IS Level 1
Protocol-ID: IS-IS Level 2, The NLRI information has been sourced Protocol-ID = 2: IS-IS Level 2, The NLRI information has been
by IS-IS Level 2 sourced by IS-IS Level 2
Protocol-ID = 3: OSPF, The NLRI information has been sourced by Protocol-ID = 3: OSPF, The NLRI information has been sourced by
OSPF OSPF
Protocol-ID = 4: Direct, The NLRI information has been sourced Protocol-ID = 4: Direct, The NLRI information has been sourced
from local interface state from local interface state
Protocol-ID = 5: Static, The NLRI information has been sourced by Protocol-ID = 5: Static, The NLRI information has been sourced by
static configuration static configuration
Both OSPF and IS-IS may run multiple routing protocol instances over Both OSPF and IS-IS may run multiple routing protocol instances over
the same link. See [I-D.ietf-isis-mi] and [RFC6549]. The 'Instance the same link. See [RFC6822] and [RFC6549].
Identifier' field identifies the protocol instance.
Identifier TLV is a mandatory TLV containing identifiers of the NLRI
and used to associate the NLRI to an instance, a domain, an area or a
prefix.
Each Node Descriptor and Link Descriptor consists of one or more TLVs Each Node Descriptor and Link Descriptor consists of one or more TLVs
described in the following sections. The sender of an UPDATE message described in the following sections. The sender of an UPDATE message
MUST order the TLVs within a Node Descriptor or a Link Descriptor in MUST order the TLVs within a Node Descriptor or a Link Descriptor in
ascending order of TLV type." ascending order of TLV type.
3.2.1. Node Descriptors 3.2.1. Identifier TLV
Identifier TLV (Type 256) is a mandatory TLV that appear in Node,
Link and Prefix NLRIs. Identifier TLV carries all identifiers
associated with the NLRI in a SubTLV format. Possible Sub TLVs are
Instance Identifier, Domain Identifier, Area Identifier, OSPF Route
Type and Multi-Topology ID.
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identifier Sub-TLVs (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Where:
Type: 256
Length: variable
Identifier Sub-TLVs: Identifiers
Figure 10: Identifier TLV Format
An Identifier may be used to distinguish a Node, a Link or a Prefix
with different types of identifiers. Therefore different SubTLVs are
defined here below in order to address the different requirements.
3.2.1.1. Instance Identifier SubTLV
Instance Identifier is a mandatory SubTLV that MUST be present in all
NLRIs. It is used to identify the topology instance the content of
the NLRI and attributes refers to.
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Instance Identifier (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Where:
Type: 1
Length: variable
Figure 11: Instance Identifier Sub-TLV Format
3.2.1.2. Domain Identifier SubTLV
Domain Identifier is an optional SubTLV that MAY be present in all
NLRIs. It is used to identify the domain (or sub-domain) to which
the NLRI belongs.
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Domain Identifier (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Where:
Type: 2
Length: variable
Figure 12: Domain Identifier Sub-TLV Format
3.2.1.3. Area Identifier SubTLV
Area Identifier is an optional SubTLV that MAY be present in all
NLRIs. It is used to identify the area to which the NLRI belongs.
Example: an OSPF ABR router advertises itself multiple time (one for
each area it participates into). Area Identifier allows the
different NLRIs of the same router to be discriminated.
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Area Identifier (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Where:
Type: 3
Length:variable
Figure 13: Area Identifier Sub-TLV Format
3.2.1.4. OSPF Route Type SubTLV
Route Type is an optional SubTLV that MAY be present in the Prefix
NLRIs. It is used to identify the OSPF route-type of the prefix. It
is used when an OSPF prefix is advertised in the OSPF domain with
multiple different route-types. The Route Type Identifier allows to
discriminate these advertisements.
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Type |
+-+-+-+-+-+-+-+-+
Where:
Type: 4
Length: 1
Figure 14: OSPF Route Type Sub-TLV Format
OSPF Route Type can be either: Intra-Area (0x1), Inter-Area (0x2),
External 1 (0x3), External 2 (0x4), NSSA (0x5) and is encoded in a 3
bits number. For prefixes learned from IS-IS, this field MUST to be
set to 0x0 on transmission.
3.2.1.5. Multi Topology ID SubTLV
The Multi Topology ID SubTLV (type: 5) carries the Multi Topology ID
for the link, node or prefix. The semantics of the Multi Topology ID
are defined in RFC5120, Section 7.2 [RFC5120], and the OSPF Multi
Topology ID), defined in RFC4915, Section 3.7 [RFC4915]. If the
value in the Multi Topology ID TLV is derived from OSPF, then the
upper 9 bits of the Multi Topology ID are set to 0.
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R R R R| Multi Topology ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 15: Multi Topology ID SubTLV format
The Multi Topology Identifier SubTLV is present in any NLRI Type.
3.2.2. Node Descriptors
Each link gets anchored by at least a pair of router-IDs. Since Each link gets anchored by at least a pair of router-IDs. Since
there are many Router-IDs formats (32 Bit IPv4 router-ID, 56 Bit ISO there are many Router-IDs formats (32 Bit IPv4 router-ID, 56 Bit ISO
Node-ID and 128 Bit IPv6 router-ID) a link may be anchored by more Node-ID and 128 Bit IPv6 router-ID) a link may be anchored by more
than one Router-ID pair. The set of Local and Remote Node than one Router-ID pair. The set of Local and Remote Node
Descriptors describe which Protocols Router-IDs will be following to Descriptors describe which Protocols Router-IDs will be following to
"anchor" the link described by the "Link attribute TLVs". There must "anchor" the link described by the "Link attribute TLVs". There must
be at least one "like" router-ID pair of a Local Node Descriptors and be at least one "like" router-ID pair of a Local Node Descriptors and
a Remote Node Descriptors per-protocol. If a peer sends an illegal a Remote Node Descriptors per-protocol. If a peer sends an illegal
combination in this respect, then this is handled as an NLRI error, combination in this respect, then this is handled as an NLRI error,
described in [RFC4760]. described in [RFC4760].
It is desirable that the Router-ID assignments inside the Node anchor It is desirable that the Router-ID assignments inside the Node anchor
are globally unique. However there may be router-ID spaces (e.g. are globally unique. However there may be router-ID spaces (e.g.
ISO) where not even a global registry exists, or worse, Router-IDs ISO) where not even a global registry exists, or worse, Router-IDs
have been allocated following private-IP RFC 1918 [RFC1918] have been allocated following private-IP RFC 1918 [RFC1918]
allocation. In order to disambiguate the Router-IDs the local and allocation. We use AS Number (or Confederation ID) and BGP
remote Autonomous System number TLVs of the anchor nodes MUST be Identifier in order to disambiguate the Router-IDs, as described in
included in the NLRI. If the anchor node's AS is a member of an AS Section 3.2.2.4.
Confederation ([RFC5065]), then the Autonomous System number TLV
contains the confederations' AS Confederation Identifier and the
Member-AS TLV is included in the NLRI. The Local and Remote
Autonomous System TLVs are 4 octets wide as described in [RFC4893].
2-octet AS Numbers SHALL be expanded to 4-octet AS Numbers by zeroing
the two MSB octets.
3.2.1.1. Local Node Descriptors 3.2.2.1. Local Node Descriptors
The Local Node Descriptors TLV (Type 256) contains Node Descriptors The Local Node Descriptors TLV (Type 257) contains Node Descriptors
for the node anchoring the local end of the link. The length of this for the node anchoring the local end of the link. The length of this
TLV is variable. The value contains one or more Node Descriptor Sub- TLV is variable. The value contains one or more Node Descriptor Sub-
TLVs defined in Section 3.2.1.3. TLVs defined in Section 3.2.2.3.
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| Node Descriptor Sub-TLVs (variable) | | Node Descriptor Sub-TLVs (variable) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: Local Node Descriptors TLV format Figure 16: Local Node Descriptors TLV format
3.2.1.2. Remote Node Descriptors 3.2.2.2. Remote Node Descriptors
The Remote Node Descriptors TLV (Type 257) contains Node Descriptors The Remote Node Descriptors TLV (Type 258) contains Node Descriptors
for the node anchoring the remote end of the link. The length of for the node anchoring the remote end of the link. The length of
this TLV is variable. The value contains one or more Node Descriptor this TLV is variable. The value contains one or more Node Descriptor
Sub-TLVs defined in Section 3.2.1.3. Sub-TLVs defined in Section 3.2.2.3.
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| Node Descriptor Sub-TLVs (variable) | | Node Descriptor Sub-TLVs (variable) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11: Remote Node Descriptors TLV format Figure 17: Remote Node Descriptors TLV format
3.2.1.3. Node Descriptor Sub-TLVs 3.2.2.3. Node Descriptor Sub-TLVs
The Node Descriptor Sub-TLV type codepoints and lengths are listed in The Node Descriptor Sub-TLV type codepoints and lengths are listed in
the following table: the following table:
+------+-------------------+--------+ +------------+-------------------+----------+
| Type | Description | Length | | TLV/SubTLV | Description | Length |
+------+-------------------+--------+ +------------+-------------------+----------+
| 258 | Autonomous System | 4 | | 259 | Autonomous System | 4 |
| 259 | Member-AS | 4 | | 260 | BGP Identifier | 4 |
| 260 | ISO Node-ID | 7 | | 261 | ISO Node-ID | 7 |
| 261 | IPv4 Router-ID | 5 | | 262 | IPv4 Router-ID | variable |
| 262 | IPv4 Router-ID | 17 | | 263 | IPv6 Router-ID | 16 |
+------+-------------------+--------+ +------------+-------------------+----------+
Table 1: Node Descriptor Sub-TLVs Table 1: Node Descriptor Sub-TLVs
The TLV values in Node Descriptor Sub-TLVs are defined as follows: The TLV values in Node Descriptor Sub-TLVs are defined as follows:
Autonomous System: opaque value (32 Bit AS ID) Autonomous System: opaque value (32 Bit AS Number)
Member-AS: opaque value (32 Bit AS ID); only included if the node is BGP-Identifier: opaque value (32 Bit AS ID); uniquely identifying
in an AS confederation. the BGP-LS speaker within an AS.
IPv4 Router ID: opaque value (can be an IPv4 address or an 32 Bit IPv4 Router ID: opaque value (can be an IPv4 address or an 32 Bit
router ID). router ID). When encoding an OSPF Designated Router ID, the
length is 8 (first 4 bytes is the Router-ID originating the Type-2
LSA and next 4 bytes are taken from the Type-2 LSA ID). In other
cases, the length is 4.
IPv6 Router ID: opaque value (can be an IPv6 address or 128 Bit IPv6 Router ID: opaque value (can be an IPv6 address or 128 Bit
router ID). router ID).
ISO Node ID: ISO node-ID (6 octets ISO system-ID) followed by a PSN ISO Node ID: ISO node-ID (6 octets ISO system-ID) followed by a PSN
octet in case LAN "Pseudonode" information gets advertised. The octet in case LAN "Pseudonode" information gets advertised. The
PSN octet must be zero for non-LAN "Pseudonodes". PSN octet must be zero for non-LAN "Pseudonodes".
There can be at most one instance of each TLV type present in any There can be at most one instance of each TLV type present in any
Node Descriptor. The TLV ordering within a Node descriptor MUST Node Descriptor. The TLV ordering within a Node descriptor MUST
be kept in order of increasing numeric value of type. TLVs 258 be kept in order of increasing numeric value of type. TLVs 259
and 259 specify administrative context in which TLVs 260-262 are and 260 specify administrative context in which TLVs 261-263 are
to be evaluated. The first TLV from range 260-262 is to be to be evaluated. The first TLV from range 261-263 is to be
interpreted as the primary node identifier, e.g. it acts as the interpreted as the primary node identifier by which the node can
unique key by which the node can be referenced within its be referenced within its administrative contexts. Any further
administrative contexts. Any further TLVs are to be treated as TLVs are to be treated as secondary identifiers, which may be used
secondary identifiers, which may be used for cross-reference, but for cross-reference, but are to be treated as if they are object
are to be treated as if they are object attributes. attributes.
3.2.1.4. Router-ID Anchoring Example: ISO Pseudonode 3.2.2.4. Globally Unique BGP-LS Identifiers
One problem that needs to be addressed is the ability to identify an
IGP node globally (by "global", we mean within the BGP-LS database
collected by all BGP-LS speakers that talk to each other). This can
be expressed through the following two requirements:
(A) The same node must not be represented by two keys (otherwise one
node will look like two nodes).
(B) Two different nodes must not be represented by the same key
(otherwise, two nodes will look like one node).
We define an "IGP domain" to be the set of nodes (and links), within
which, each node has a unique IGP representation by using the
combination of area-id, IGP router-id, Level, instance ID, etc. The
problem is that BGP brings nodes from multiple independent "IGP
domains" and we need to distinguish between them. Moreover, we can't
assume there is always one and only one IGP domain per Autonomous
System (or Autonomous System confederation member). Following cases
illustrate scenario's where IGP domain and ASs boundaries do not
match.
(i) Stub ASs or non-contiguous AS: One can have an AS that has
disjoint parts, each running an independent IGP domain.
IGP domain 1 IGP domain 2
AS 1 AS 1
+---+ +---+
| | | |
+---+ +---+
\ /
+---------+
| |
+---------+
Transit AS
Figure 18: Stub-ASs or non-contiguous AS
Using ASN to globally identify IGP node may break requirement (B).
(ii) It is possible to run the same IGP domain across multiple AS.
+----------------------+
| +------+ +------+ |
| | AS 1 | | AS 2 | |
| +------+ +------+ |
+----------------------+
IGP domain
Figure 19: IGP Domain
Using ASN to globally identify IGP node will break requirement (A).
(iii) It is possible to run IGP across member-ASs in a confederation.
+-------------------------------+
| +--------------------------+ |
| | +--------+ +--------+ | |
| | | member | | member | | |
| | | AS 1 | | AS 2 | | |
| | +--------+ +--------+ | |
| +--------------------------+ |
| IGP domain |
+-------------------------------+
Confederation (confed-id 1)
Figure 20: Confederation
Using a Confederation/MemberAS identifier to globally identify IGP
node will break requirement (A).
(iv) It is possible to run more than one IGP domain within an AS by
setting up "transit BGP speakers".
+---------------------------------+
| +----------+ +----------+ |
| | IGP | +---+ | IGP | |
| | domain 1 +-+ +-+ domain 2 | |
| +----------+ +---+ +----------+ |
| ^ |
| | |
| Transit BGP node |
+---------------------------------+
AS 1
Figure 21: Transit BGP Node
Using ASN to globally identify IGP node may break requirement (A).
In summary, there is no strict relation between BGP AS division and
IGP domains. Therefore, the following mechanism is proposed to
address the requirements. We assume that a BGP-LS speaker is
collocated with one and only one IGP node. The BGP-LS speaker
originates BGP-LS NLRIs that correspond to the objects in the LSDB of
that IGP node.
We embed a "string" (identifier) in the node descriptor to globally
identify the node. The question is how we construct such a string,
and what should be the scope of such a string so that the
construction of the string can be simple. Let the set of IGP nodes
within which LSA/LSP flooding is limited to be the "flooding set".
Consider a given "flooding set". We have the following three
possibilities:
Case a) There is no BGP LS speaker running on any node in the
flooding set.
Case b) There is one BGP LS speaker running on one node in the
flooding set.
Case c) There is more than one BGP LS speakers running on the nodes
in the flooding set.
For Case a), the nodes in that flooding set do not appear in BGP LS
database. So we can ignore that case for this discussion. To
satisfy requirement (B), the string we use in different IGP domains
must be different. One possible approach is as follows:
Approach 1) The user configures a unique "string" on all BGP LS
speakers within one IGP domain.
Now we make an observation that simplifies the task: it is sufficient
to have a unique "string" per flooding set.
When we have a unique string per flooding set, then two nodes in
different IGP domains, which by definition belong to different
flooding sets, would have different "strings". So requirement B) is
satisfied. On the other hand, a given node appears only in the LSDB
of the nodes in the same flooding set. So a given node will always
have only one "string" and we satisfy requirement A). Given this, we
have:
Approach 2) Each BGP LS speaker uses the <Autonomous System Number,
BGP Identifier> as the string.
The combination of <Autonomous System, BGP Identifier> is globally
unique, as per [RFC6286].
For Case b), which is the simplest BGP-LS deployment scenario, this
approach requires no additional configuration from the user.
For Case c), however, if each BGP-LS speaker in the given flooding
set attaches its own <Autonomous System, BGP Identifier>, then we
will violate requirement A). So that case, the user needs to choose
one of the BGP-LS speakers in the flooding set as the "chosen
speaker" and configure the rest of the BGP-LS speakers in that
flooding set to use the <Autonomous System, BGP Identifier>
combination of the "chosen speaker".
When an IGP node belongs to two or more flooding sets, it views
itself as a collocation of one node per flooding set and accordingly
encodes the NLRIs. Consider the following example:
Level-1 level-1-2 level-1
N1 N0 N2
+---+ link1 +---+ link 2 +---+
| +-------+ +---------+ |
+---+ +---+ +---+
|<- Level 1 ->| |<- level 2 ->|
L11 L12
"str1" "str2"
Figure 22: IGP Node in multiple flooding sets
The node N0 is a level 1-2 node. Link1 belongs to level 1 area L11,
which has string "str1". Link2 belongs to level 1 area L12 which has
string "str2". N0 has both link1 and link2 in its LSDB. If BGP LS
speaker is running on N0, then N0 views itself as a collocation of
two nodes: N0(L11) and N0(L12) and originate <str1, N1, N0> and
<str2, N0, N2>.
To sum up, the mechanism works as follows:
1. We use <Autonomous System, BGP Identifier> as the
disambiguating string.
2. By default, a BGP-LS speaker uses its own ASN, BGP identifier
(router-id) for these fields for the NLRIs it originates.
3. Operator has the ability to configure other <ASN, BGP ID> per
flooding set the IGP node underneath belongs to. In that case,
the node descriptor(s) for a given NLRI uses the string
corresponding to the flooding set where the node belongs.
The operator needs to provide the configuration if there are multiple
BGP-LS speakers running in the same flooding set.
3.2.2.5. Router-ID Anchoring Example: ISO Pseudonode
IS-IS Pseudonodes are a good example for the variable Router-ID IS-IS Pseudonodes are a good example for the variable Router-ID
anchoring. Consider Figure 12. This represents a Broadcast LAN anchoring. Consider Figure 23. This represents a Broadcast LAN
between a pair of routers. The "real" (=non pseudonode) routers have between a pair of routers. The "real" (=non pseudonode) routers have
both an IPv4 Router-ID and IS-IS Node-ID. The pseudonode does not both an IPv4 Router-ID and IS-IS Node-ID. The pseudonode does not
have an IPv4 Router-ID. Two unidirectional links (Node1, Pseudonode have an IPv4 Router-ID. Two unidirectional links (Node1, Pseudonode
1) and (Pseudonode 1, Node 2) are being generated. 1) and (Pseudonode 1, Node 2) are being generated.
The NRLI for (Node1, Pseudonode1) encodes local IPv4 router-ID, local The NRLI for (Node1, Pseudonode1) encodes local IPv4 router-ID, local
ISO node-ID and remote ISO node-id) ISO node-ID and remote ISO node-id)
The NLRI for (Pseudonode1, Node2) encodes a local ISO node-ID and The NLRI for (Pseudonode1, Node2) encodes a local ISO node-ID and
remote ISO node-id. remote ISO node-id.
+-----------------+ +-----------------+ +-----------------+ +-----------------+ +-----------------+ +-----------------+
| Node1 | | Pseudonode 1 | | Node2 | | Node1 | | Pseudonode 1 | | Node2 |
|1920.0000.2001.00|--->|1921.6800.1001.02|--->|1920.0000.2002.00| |1920.0000.2001.00|--->|1920.0000.2001.02|--->|1920.0000.2002.00|
| 192.0.2.1 | | | | 192.0.2.2 | | 192.0.2.1 | | | | 192.0.2.2 |
+-----------------+ +-----------------+ +-----------------+ +-----------------+ +-----------------+ +-----------------+
Figure 12: IS-IS Pseudonodes Figure 23: IS-IS Pseudonodes
3.2.1.5. Router-ID Anchoring Example: OSPFv2 to IS-IS Migration 3.2.2.6. Router-ID Anchoring Example: OSPFv2 to IS-IS Migration
Migrating gracefully from one IGP to another requires congruent Migrating gracefully from one IGP to another requires congruent
operation of both routing protocols during the migration period. The operation of both routing protocols during the migration period. The
target protocol (IS-IS) supports more router-ID spaces than the target protocol (IS-IS) supports more router-ID spaces than the
source (OSPFv2) protocol. When advertising a point-to-point link source (OSPFv2) protocol. When advertising a point-to-point link
between an OSPFv2-only router and an OSPFv2 and IS-IS enabled router between an OSPFv2-only router and an OSPFv2 and IS-IS enabled router
the following link information may be generated. Note that the IS-IS the following link information may be generated. Note that the IS-IS
router also supports the IPv6 traffic engineering extensions RFC 6119 router also supports the IPv6 traffic engineering extensions RFC 6119
[RFC6119] for IS-IS. [RFC6119] for IS-IS.
The NRLI encodes local IPv4 router-id, remote IPv4 router-id, remote The NRLI encodes local IPv4 router-id, remote IPv4 router-id, remote
ISO node-id and remote IPv6 node-id. ISO node-id and remote IPv6 node-id.
3.2.2. Link Descriptors 3.2.3. Link Descriptors
The 'Link Descriptor' field is a set of Type/Length/Value (TLV) The 'Link Descriptor' field is a set of Type/Length/Value (TLV)
triplets. The format of each TLV is shown in Section 3.1. The 'Link triplets. The format of each TLV is shown in Section 3.1. The 'Link
descriptor' TLVs uniquely identify a link between a pair of anchor descriptor' TLVs uniquely identify a link between a pair of anchor
Routers. A link described by the Link descriptor TLVs actually is a Routers. A link described by the Link descriptor TLVs actually is a
"half-link", a unidirectional representation of a logical link. In "half-link", a unidirectional representation of a logical link. In
order to fully describe a single logical link two originating routers order to fully describe a single logical link two originating routers
need to advertise a half-link each, i.e. two link NLRIs will be need to advertise a half-link each, i.e. two link NLRIs will be
advertised. advertised.
The format and semantics of the 'value' fields in most 'Link The format and semantics of the 'value' fields in most 'Link
Descriptor' TLVs correspond to the format and semantics of value Descriptor' TLVs correspond to the format and semantics of value
fields in IS-IS Extended IS Reachability sub-TLVs, defined in fields in IS-IS Extended IS Reachability sub-TLVs, defined in
[RFC5305], [RFC5307] and [RFC6119]. Although the encodings for 'Link [RFC5305], [RFC5307] and [RFC6119]. Although the encodings for 'Link
Descriptor' TLVs were originally defined for IS-IS, the TLVs can Descriptor' TLVs were originally defined for IS-IS, the TLVs can
carry data sourced either by IS-IS or OSPF. carry data sourced either by IS-IS or OSPF.
The following link descriptor TLVs are valid in the Link NLRI: The following link descriptor TLVs are valid in the Link NLRI:
+------+------------------------+-----------------+-----------------+ +------------+--------------------+---------------+-----------------+
| Type | Description | IS-IS | Value defined | | TLV/SubTLV | Description | IS-IS | Value defined |
| | | TLV/Sub-TLV | in: | | | | TLV/Sub-TLV | in: |
+------+------------------------+-----------------+-----------------+ +------------+--------------------+---------------+-----------------+
| 263 | Link Local/Remote | 22/4 | [RFC5307]/1.1 | | 264 | Link Local/Remote | 22/4 | [RFC5307]/1.1 |
| | Identifiers | | | | | Identifiers | | |
| 264 | IPv4 interface address | 22/6 | [RFC5305]/3.2 | | 265 | IPv4 interface | 22/6 | [RFC5305]/3.2 |
| 265 | IPv4 neighbor address | 22/8 | [RFC5305]/3.3 | | | address | | |
| 266 | IPv6 interface address | 22/12 | [RFC6119]/4.2 | | 266 | IPv4 neighbor | 22/8 | [RFC5305]/3.3 |
| 267 | IPv6 neighbor address | 22/13 | [RFC6119]/4.3 | | | address | | |
| 268 | Multi Topology ID | --- | Section 3.2.2.1 | | 267 | IPv6 interface | 22/12 | [RFC6119]/4.2 |
+------+------------------------+-----------------+-----------------+ | | address | | |
| 268 | IPv6 neighbor | 22/13 | [RFC6119]/4.3 |
| | address | | |
| 256/5 | Multi Topology ID | --- | Section 3.2.1.5 |
+------------+--------------------+---------------+-----------------+
Table 2: Link Descriptor TLVs Table 2: Link Descriptor TLVs
3.2.2.1. Multi Topology ID TLV 3.2.4. Prefix Descriptors
The Multi Topology ID TLV (Type 268) carries the Multi Topology ID The 'Prefix descriptor' TLVs uniquely identify a Prefix (IPv4 or
for this link. The semantics of the Multi Topology ID are defined in IPv6) originated by a Node.
RFC5120, Section 7.2 [RFC5120], and the OSPF Multi Topology ID),
defined in RFC4915, Section 3.7 [RFC4915]. If the value in the Multi
Topology ID TLV is derived from OSPF, then the upper 9 bits of the
Multi Topology ID are set to 0.
0 1 2 3 The following Prefix descriptor TLVs are valid in the IPv4/IPv6
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 Prefix NLRI:
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R R R R| Multi Topology ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 13: Multi Topology ID TLV format +------------+-----------------+-----------------+------------------+
| TLV/SubTLV | Description | IS-IS | Value defined |
| | | TLV/Sub-TLV | in: |
+------------+-----------------+-----------------+------------------+
| 256/5 | Multi Topology | --- | Section 3.2.1.5 |
| | ID | | |
+------------+-----------------+-----------------+------------------+
3.2.3. The Prefix NLRI Table 3: Prefix Descriptor TLVs
The Prefix NLRI is a variable length field that contains an IP 3.2.4.1. The Prefix NLRI
address prefix (IPv4 or IPv6) originally advertised in the IGP
topology. The distinction between IPv4 and IPv6 prefixes is given by The Prefix NLRI is a variable length field that contains one or more
the NLRI Type filed in the Link State NLRI. Reachability information IP address prefixes (IPv4 or IPv6) originally advertised in the IGP
is encoded as one or more 2-tuples of the form <length, prefix>, topology. The NLRI Type determines the address-family. Reachability
whose fields are described below: information is encoded as one or more 2-tuples of the form <length,
prefix>, whose fields are described below:
+---------------------------+ +---------------------------+
| Length (1 octet) | | Length (1 octet) |
+---------------------------+ +---------------------------+
| Prefix (variable) | | Prefix (variable) |
+---------------------------+ +---------------------------+
Figure 14: Prefix NLRI format Figure 24: Prefix NLRI format
The 'Length' field contains the length of the prefix in bits. Only
the most significant octets of the prefix are encoded. I.e. 1 octet
for prefix length 1 up to 8, 2 octets for prefix length 9 to 16, 3
octets for prefix length 17 up to 24 and 4 octets for prefix length
25 up to 32, etc.
3.3. The LINK_STATE Attribute 3.3. The LINK_STATE Attribute
This is an optional, transitive BGP attribute that is used to carry This is an optional, non-transitive BGP attribute that is used to
link, node and prefix parameters and attributes. It is defined as a carry link, node and prefix parameters and attributes. It is defined
set of Type/Length/Value (TLV) triplets, described in the following as a set of Type/Length/Value (TLV) triplets, described in the
section. This attribute SHOULD only be included with Link State following section. This attribute SHOULD only be included with Link
NLRIs. This attribute MUST be ignored for all other NLRIs. State NLRIs. This attribute MUST be ignored for all other NLRIs.
3.3.1. Link Attribute TLVs 3.3.1. Link Attribute TLVs
Each 'Link Attribute' is a Type/Length/Value (TLV) triplet formatted Each 'Link Attribute' is a Type/Length/Value (TLV) triplet formatted
as defined in Section 3.1. The format and semantics of the 'value' as defined in Section 3.1. The format and semantics of the 'value'
fields in some 'Link Attribute' TLVs correspond to the format and fields in some 'Link Attribute' TLVs correspond to the format and
semantics of value fields in IS-IS Extended IS Reachability sub-TLVs, semantics of value fields in IS-IS Extended IS Reachability sub-TLVs,
defined in [RFC5305] and [RFC5307]. Other 'Link Attribute' TLVs are defined in [RFC5305] and [RFC5307]. Other 'Link Attribute' TLVs are
defined in this document. Although the encodings for 'Link defined in this document. Although the encodings for 'Link
Attribute' TLVs were originally defined for IS-IS, the TLVs can carry Attribute' TLVs were originally defined for IS-IS, the TLVs can carry
data sourced either by IS-IS or OSPF. data sourced either by IS-IS or OSPF.
The following 'Link Attribute' TLVs are are valid in the LINK_STATE The following 'Link Attribute' TLVs are are valid in the LINK_STATE
attribute: attribute:
+------+-------------------------+----------------+-----------------+ +------------+---------------------+--------------+-----------------+
| Type | Description | IS-IS | Defined in: | | TLV/SubTLV | Description | IS-IS | Defined in: |
| | | TLV/Sub-TLV | | | | | TLV/Sub-TLV | |
+------+-------------------------+----------------+-----------------+ +------------+---------------------+--------------+-----------------+
| 269 | Administrative group | 22/3 | [RFC5305]/3.1 | | 256/3 | Area Identifier | --- | Section 3.2.1.3 |
| | (color) | | | | 269 | Administrative | 22/3 | [RFC5305]/3.1 |
| 270 | Maximum link bandwidth | 22/9 | [RFC5305]/3.3 | | | group (color) | | |
| 271 | Max. reservable link | 22/10 | [RFC5305]/3.5 | | 270 | Maximum link | 22/9 | [RFC5305]/3.3 |
| | bandwidth | | | | | bandwidth | | |
| 272 | Unreserved bandwidth | 22/11 | [RFC5305]/3.6 | | 271 | Max. reservable | 22/10 | [RFC5305]/3.5 |
| 273 | Link Protection Type | 22/20 | [RFC5307]/1.2 | | | link bandwidth | | |
| 274 | MPLS Protocol Mask | --- | Section 3.3.1.1 | | 272 | Unreserved | 22/11 | [RFC5305]/3.6 |
| 275 | Metric | --- | Section 3.3.1.2 | | | bandwidth | | |
| 276 | Shared Risk Link Group | --- | Section 3.3.1.3 | | 273 | TE Default Metric | 22/18 | [RFC5305]/3.7 |
| 277 | OSPF specific link | --- | Section 3.3.1.4 | | 274 | Link Protection | 22/20 | [RFC5307]/1.2 |
| | attribute | | | | | Type | | |
| 278 | IS-IS Specific Link | --- | Section 3.3.1.5 | | 275 | MPLS Protocol Mask | --- | Section 3.3.1.1 |
| | Attribute | | | | 276 | Metric | --- | Section 3.3.1.2 |
| 279 | Area ID | --- | Section 3.3.1.6 | | 277 | Shared Risk Link | --- | Section 3.3.1.3 |
+------+-------------------------+----------------+-----------------+ | | Group | | |
| 278 | OSPF specific link | --- | Section 3.3.1.4 |
| | attribute | | |
| 279 | IS-IS Specific Link | --- | Section 3.3.1.5 |
| | Attribute | | |
+------------+---------------------+--------------+-----------------+
Table 3: Link Attribute TLVs Table 4: Link Attribute TLVs
3.3.1.1. MPLS Protocol Mask TLV 3.3.1.1. MPLS Protocol Mask TLV
The MPLS Protocol TLV (Type 274) carries a bit mask describing which The MPLS Protocol TLV (Type 275) carries a bit mask describing which
MPLS signaling protocols are enabled. The length of this TLV is 1. MPLS signaling protocols are enabled. The length of this TLV is 1.
The value is a bit array of 8 flags, where each bit represents an The value is a bit array of 8 flags, where each bit represents an
MPLS Protocol capability. MPLS Protocol capability.
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L R | |L R |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Figure 15: MPLS Protocol TLV Figure 25: MPLS Protocol TLV
The following bits are defined: The following bits are defined:
+-----+---------------------------------------------+-----------+ +-----+---------------------------------------------+-----------+
| Bit | Description | Reference | | Bit | Description | Reference |
+-----+---------------------------------------------+-----------+ +-----+---------------------------------------------+-----------+
| 0 | Label Distribution Protocol (LDP) | [RFC5036] | | 0 | Label Distribution Protocol (LDP) | [RFC5036] |
| 1 | Extension to RSVP for LSP Tunnels (RSVP-TE) | [RFC3209] | | 1 | Extension to RSVP for LSP Tunnels (RSVP-TE) | [RFC3209] |
| 2-7 | Reserved for future use | | | 2-7 | Reserved for future use | |
+-----+---------------------------------------------+-----------+ +-----+---------------------------------------------+-----------+
Table 4: MPLS Protocol Mask TLV Codes Table 5: MPLS Protocol Mask TLV Codes
3.3.1.2. Metric TLV 3.3.1.2. Metric TLV
The IGP Metric TLV (Type 275) carries the metric for this link. The The IGP Metric TLV (Type 276) carries the metric for this link. The
length of this TLV is 3. If the length of the metric from which the length of this TLV is 3. If the length of the metric from which the
IGP Metric value is derived is less than 3 (e.g. for OSPF link IGP Metric value is derived is less than 3 (e.g. for OSPF link
metrics or non-wide IS-IS metric), then the upper bits of the TLV are metrics or non-wide IS-IS metric), then the upper bits of the TLV are
set to 0. set to 0.
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IGP Link Metric | | IGP Link Metric |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 16: Metric TLV format Figure 26: Metric TLV format
3.3.1.3. Shared Risk Link Group TLV 3.3.1.3. Shared Risk Link Group TLV
The Shared Risk Link Group (SRLG) TLV (Type 276) carries the Shared The Shared Risk Link Group (SRLG) TLV (Type 277) carries the Shared
Risk Link Group information (see Section 2.3, "Shared Risk Link Group Risk Link Group information (see Section 2.3, "Shared Risk Link Group
Information", of [RFC4202]). It contains a data structure consisting Information", of [RFC4202]). It contains a data structure consisting
of a (variable) list of SRLG values, where each element in the list of a (variable) list of SRLG values, where each element in the list
has 4 octets, as shown in Figure 17. The length of this TLV is 4 * has 4 octets, as shown in Figure 27. The length of this TLV is 4 *
(number of SRLG values). (number of SRLG values).
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Shared Risk Link Group Value | | Shared Risk Link Group Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| ............ | | ............ |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Shared Risk Link Group Value | | Shared Risk Link Group Value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 17: Shared Risk Link Group TLV format Figure 27: Shared Risk Link Group TLV format
Note that there is no SRLG TLV in OSPF-TE. In IS-IS the SRLG Note that there is no SRLG TLV in OSPF-TE. In IS-IS the SRLG
information is carried in two different TLVs: the IPv4 (SRLG) TLV information is carried in two different TLVs: the IPv4 (SRLG) TLV
(Type 138) defined in [RFC5307], and the IPv6 SRLG TLV (Type 139) (Type 138) defined in [RFC5307], and the IPv6 SRLG TLV (Type 139)
defined in [RFC6119]. Since the Link State NLRI uses variable defined in [RFC6119]. Since the Link State NLRI uses variable
Router-ID anchoring, both IPv4 and IPv6 SRLG information can be Router-ID anchoring, both IPv4 and IPv6 SRLG information can be
carried in a single TLV. carried in a single TLV.
3.3.1.4. OSPF Specific Link Attribute TLV 3.3.1.4. OSPF Specific Link Attribute TLV
The OSPF specific link attribute TLV (Type 277) is an envelope that The OSPF specific link attribute TLV (Type 278) is an envelope that
transparently carries optional link properties TLVs advertised by an transparently carries optional link properties TLVs advertised by an
OSPF router. The value field contains one or more optional OSPF link OSPF router. The value field contains one or more optional OSPF link
attribute TLVs. An originating router shall use this TLV for attribute TLVs. An originating router shall use this TLV for
encoding information specific to the OSPF protocol or new OSPF encoding information specific to the OSPF protocol or new OSPF
extensions for which there is no protocol neutral representation in extensions for which there is no protocol neutral representation in
the BGP link-state NLRI. the BGP link-state NLRI.
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| OSPF specific link attributes (variable) | | OSPF specific link attributes (variable) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 18: OSPF specific link attribute format Figure 28: OSPF specific link attribute format
3.3.1.5. IS-IS specific link attribute TLV 3.3.1.5. IS-IS specific link attribute TLV
The IS-IS specific link attribute TLV (Type 278) is an envelope that The IS-IS specific link attribute TLV (Type 279) is an envelope that
transparently carries optional link properties TLVs advertised by an transparently carries optional link properties TLVs advertised by an
IS-IS router. The value field contains one or more optional IS-IS IS-IS router. The value field contains one or more optional IS-IS
link attribute TLVs. An originating router shall use this TLV for link attribute TLVs. An originating router shall use this TLV for
encoding information specific to the IS-IS protocol or new IS-IS encoding information specific to the IS-IS protocol or new IS-IS
extensions for which there is no protocol neutral representation in extensions for which there is no protocol neutral representation in
the BGP link-state NLRI. the BGP link-state NLRI.
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| IS-IS specific link attributes (variable) | | IS-IS specific link attributes (variable) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 19: IS-IS specific link attribute format Figure 29: IS-IS specific link attribute format
3.3.1.6. Link Area TLV
The Area TLV (Type 279) carries the Area ID which is assigned on this
link. If a link is present in more than one Area then several
occurrences of this TLV may be generated. Since only the OSPF
protocol carries the notion of link specific areas, the Area ID has a
fixed length of 4 octets.
0 1 2 3 3.3.1.6. IS-IS Area Address attribute TLV
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Area ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 20: Link Area TLV format The area address is carried in the Area Identifier SubTLV of the
Identifier TLV and consists of the Area Address which is assigned to
the link. If more than one Area Addresses are present, only the
lower address is encoded. Note that the Area Identifier SubTLV may
appear in all NLRI types (Link, Node and Prefix) and is defined in
Section 3.2.1.3.
3.3.2. Node Attribute TLVs 3.3.2. Node Attribute TLVs
The following node attribute TLVs are defined: The following node attribute TLVs are defined:
+------+--------------------------------+----------+ +------------+--------------------------------------+----------+
| Type | Description | Length | | TLV/SubTLV | Description | Length |
+------+--------------------------------+----------+ +------------+--------------------------------------+----------+
| 280 | Multi Topology | 2 | | 256/5 | Multi Topology | 2 |
| 281 | Node Flag Bits | 1 | | 280 | Node Flag Bits | 1 |
| 282 | OSPF Specific Node Properties | variable | | 281 | OSPF Specific Node Properties | variable |
| 283 | IS-IS Specific Node Properties | variable | | 282 | IS-IS Specific Node Properties | variable |
| 284 | Node Area ID | variable | | 256 | IS-IS Area Address/Domain Identifier | variable |
+------+--------------------------------+----------+ +------------+--------------------------------------+----------+
Table 5: Node Attribute TLVs
3.3.2.1. Multi Topology Node TLV
The Multi Topology TLV (Type 280) carries the Multi Topology ID and Table 6: Node Attribute TLVs
topology specific flags for this node. The format and semantics of
the 'value' field in the Multi Topology TLV is defined in RFC5120,
Section 7.1 [RFC5120]. If the value in the Multi Topology TLV is
derived from OSPF, then the upper 9 bits of the Multi Topology ID and
the 'O' and 'A' bits are set to 0.
0 1 2 3 3.3.2.1. Node Multi Topology ID
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|O A R R| Multi Topology ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 21: Multi Topology Node TLV format The Node Multi Topology ID is carried in the Multi Topolofy ID SubTLV
(type 5) of Identifier ID TLV TLV (Type 256) and carries the Multi
Topology ID and topology specific flags for this node. The format
and semantics of the 'value' field in the Multi Topology TLV is
defined in Section 3.2.1.5. If the value in the Multi Topology TLV
is derived from OSPF, then the upper 9 bits of the Multi Topology ID
and the 'O' and 'A' bits are set to 0.
3.3.2.2. Node Flag Bits TLV 3.3.2.2. Node Flag Bits TLV
The Node Flag Bits TLV (Type 281) carries a bit mask describing node The Node Flag Bits TLV (Type 280) carries a bit mask describing node
attributes. The value is a bit array of 8 flags, where each bit attributes. The value is a variable length bit array of flags, where
represents a node capability. each bit represents a node capability.
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Flags | | Flags (variable) |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 22: Node Flag Bits TLV format Figure 30: Node Flag Bits TLV format
The bits are defined as follows: The bits are defined as follows:
+-----+--------------+-----------+ +-----+--------------+-----------+
| Bit | Description | Reference | | Bit | Description | Reference |
+-----+--------------+-----------+ +-----+--------------+-----------+
| 0 | Overload Bit | [RFC1195] | | 0 | Overload Bit | [RFC1195] |
| 1 | Attached Bit | [RFC1195] | | 1 | Attached Bit | [RFC1195] |
| 2 | External Bit | [RFC2328] | | 2 | External Bit | [RFC2328] |
| 3 | ABR Bit | [RFC2328] | | 3 | ABR Bit | [RFC2328] |
+-----+--------------+-----------+ +-----+--------------+-----------+
Table 6: Node Flag Bits Definitions Table 7: Node Flag Bits Definitions
3.3.2.3. OSPF Specific Node Properties TLV 3.3.2.3. OSPF Specific Node Properties TLV
The OSPF Specific Node Properties TLV (Type 282) is an envelope that The OSPF Specific Node Properties TLV (Type 281) is an envelope that
transparently carries optional node properties TLVs advertised by an transparently carries optional node properties TLVs advertised by an
OSPF router. The value field contains one or more optional OSPF node OSPF router. The value field contains one or more optional OSPF node
property TLVs, such as the OSPF Router Informational Capabilities TLV property TLVs, such as the OSPF Router Informational Capabilities TLV
defined in [RFC4970], or the OSPF TE Node Capability Descriptor TLV defined in [RFC4970], or the OSPF TE Node Capability Descriptor TLV
described in [RFC5073]. An originating router shall use this TLV for described in [RFC5073]. An originating router shall use this TLV for
encoding information specific to the OSPF protocol or new OSPF encoding information specific to the OSPF protocol or new OSPF
extensions for which there is no protocol neutral representation in extensions for which there is no protocol neutral representation in
the BGP link-state NLRI. the BGP link-state NLRI.
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| OSPF specific node properties (variable) | | OSPF specific node properties (variable) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 23: OSPF specific Node property format Figure 31: OSPF specific Node property format
3.3.2.4. IS-IS Specific Node Properties TLV 3.3.2.4. IS-IS Specific Node Properties TLV
The IS-IS Router Specific Node Properties TLV (Type 283) is an The IS-IS Router Specific Node Properties TLV (Type 282) is an
envelope that transparently carries optional node specific TLVs envelope that transparently carries optional node specific TLVs
advertised by an IS-IS router. The value field contains one or more advertised by an IS-IS router. The value field contains one or more
optional IS-IS node property TLVs, such as the IS-IS TE Node optional IS-IS node property TLVs, such as the IS-IS TE Node
Capability Descriptor TLV described in [RFC5073]. An originating Capability Descriptor TLV described in [RFC5073]. An originating
router shall use this TLV for encoding information specific to the router shall use this TLV for encoding information specific to the
IS-IS protocol or new IS-IS extensions for which there is no protocol IS-IS protocol or new IS-IS extensions for which there is no protocol
neutral representation in the BGP link-state NLRI. neutral representation in the BGP link-state NLRI.
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
| IS-IS specific node properties (variable) | | IS-IS specific node properties (variable) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 24: IS-IS specific Node property format Figure 32: IS-IS specific Node property format
3.3.2.5. Area Node TLV
The Area TLV (Type 284) carries the Area ID which is assigned to this
node. If a node is present in more than one Area then several
occurrences of this TLV may be generated. Since only the IS-IS
protocol carries the notion of per-node areas, the Area ID has a
variable length of 1 to 20 octets.
0 1 2 3 3.3.2.5. ISIS Area Address TLV
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 | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Area ID (variable) |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 25: Area Node TLV format The area address is carried in the Area Identifier SubTLV of the
Identifier TLV and consists of the Area Address which is assigned to
the node. If more than one Area Addresses are present, only the
lower address is encoded. Note that the Area Identifier SubTLV may
appear in all NLRI types (Link, Node and Prefix) and is defined in
Section 3.2.1.3.
3.3.3. Prefix Attributes TLVs 3.3.3. Prefix Attributes TLVs
Prefixes are learned from the IGP topology (ISIS or OSPF) with a set Prefixes are learned from the IGP topology (ISIS or OSPF) with a set
of IGP attributes (such as metric, route tags, route type, etc.) that of IGP attributes (such as metric, route tags, etc.) that MUST be
MUST be reflected into the LINK_STATE attribute. This section reflected into the LINK_STATE attribute. This section describes the
describes the different attributes related to the IPv4/IPv6 prefixes. different attributes related to the IPv4/IPv6 prefixes. Prefix
Prefix Attributes TLVs SHOULD be used when advertising NLRI types 3 Attributes TLVs SHOULD be used when advertising NLRI types 3 and 4
and 4 only. The following attributes TLVs are defined: only. The following attributes TLVs are defined:
+------+-------------------------+--------+-----------+ +-------------------------+-------------+-----------+-----------+
| Type | Description | Length | Reference | | TLV/SubTLV | Description | Length | Reference |
+------+-------------------------+--------+-----------+ +-------------------------+-------------+-----------+-----------+
| 285 | IGP Flags | 4 | | | 283 | IGP Flags | 4 | 284 |
| 286 | Route Tag | 4 | [RFC5130] | | Route Tag | 4*n | [RFC5130] | 285 |
| 287 | Extended Tag | 8 | [RFC5130] | | Extended Tag | 8*n | [RFC5130] | 286 |
| 288 | Metric | 4 | [RFC5305] | | Prefix Metric | 4 | [RFC5305] | 287 |
| 289 | OSPF Forwarding Address | 4 | [RFC2328] | | OSPF Forwarding Address | 4 | [RFC2328] | |
+------+-------------------------+--------+-----------+ +-------------------------+-------------+-----------+-----------+
Table 7: Prefix Attribute TLVs Table 8: Prefix Attribute TLVs
3.3.3.1. IGP Flags TLV 3.3.3.1. IGP Flags TLV
IGP Flags TLV contains ISIS and OSPF flags and bits originally IGP Flags TLV contains ISIS and OSPF flags and bits originally
assigned to the prefix. The IGP Flags TLV is encoded as follows: assigned to the prefix. The IGP Flags TLV is encoded as follows:
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| IGP Flags | | IGP Flags (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 26: IGP Flag TLV format Figure 33: IGP Flag TLV format
where: where:
Type is 285 Type is 283
Length is 4 Length is variable
The following bits are defined according to the table here below: The following bits are defined according to the table here below:
+------+------------------+-----------+ +------+------------------+-----------+
| Bit | Description | Reference | | Bit | Description | Reference |
+------+------------------+-----------+ +------+------------------+-----------+
| 0 | ISIS Up/Down Bit | [RFC5305] | | 0 | ISIS Up/Down Bit | [RFC5305] |
| 1-3 | OSPF Route Type | [RFC2328] | | 1-3 | OSPF Route Type | [RFC2328] |
| 4-15 | RESERVED | | | 4-15 | RESERVED | |
+------+------------------+-----------+ +------+------------------+-----------+
Table 9: IGP Flag Bits Definitions
Table 8: IGP Flag Bits Definitions
OSPF Route Type can be either: Intra-Area (0x1), Inter-Area (0x2), OSPF Route Type can be either: Intra-Area (0x1), Inter-Area (0x2),
External 1 (0x3), External 2 (0x4), NSSA (0x5) and is encoded in a 3 External 1 (0x3), External 2 (0x4), NSSA (0x5) and is encoded in a 3
bits number. For prefixes learned from IS-IS, this field MUST to be bits number. For prefixes learned from IS-IS, this field MUST to be
set to 0x0 on transmission. set to 0x0 on transmission.
3.3.3.2. Route Tag 3.3.3.2. Route Tag
Route Tag TLV carries the original IGP TAG (ISIS or OSPF) of the Route Tag TLV carries the original IGP TAG (ISIS or OSPF) of the
prefix and is encoded as follows: prefix and is encoded as follows:
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Tag | | Route Tags (one or more) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 27: IGP Route TAG TLV format Figure 34: IGP Route TAG TLV format
where: where:
Type is 286 Type is 284
Length is 4 Length is a multiple of 4
Route Tag contains the original tags as learned in the IGP topology. One or more Route Tags as learned in the IGP topology.
3.3.3.3. Extended Route Tag 3.3.3.3. Extended Route Tag
Extended Route Tag TLV carries the ISIS Extended Route TAG of the Extended Route Tag TLV carries the ISIS Extended Route TAG of the
prefix and is encoded as follows: prefix and is encoded as follows:
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Extended Route Tag | | Extended Route Tag (one or more) |
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 28: Extended IGP Route TAG TLV format Figure 35: Extended IGP Route TAG TLV format
where: where:
Type is 287 Type is 285
Length is 8 Length is a multiple of 8
Extended Route Tag contains the original ISIS Extended Tag as learned Extended Route Tag contains one or more Extended Route Tags as
in the IGP topology. learned in the IGP topology.
3.3.3.4. Prefix Metric TLV 3.3.3.4. Prefix Metric TLV
Prefix Metric TLV carries the metric of the prefix as known in the Prefix Metric TLV carries the metric of the prefix as known in the
IGP topology. The attribute is mandatory and can only appear once. IGP topology. The attribute is mandatory and can only appear once.
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Metric | | Metric |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 29: Prefix Metric TLV Format Figure 36: Prefix Metric TLV Format
where: where:
Type is 288 Type is 286
Length is 4 Length is 4
3.3.3.5. OSPF Forwarding Address TLV 3.3.3.5. OSPF Forwarding Address TLV
OSPF Forwarding Address TLV carries the OSPF forwarding address as OSPF Forwarding Address TLV carries the OSPF forwarding address as
known in the original OSPF advertisement. Forwarding address can be known in the original OSPF advertisement. Forwarding address can be
either IPv4 or IPv6. either IPv4 or IPv6.
0 1 2 3 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 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 | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Forwarding Address (variable) | | Forwarding Address (variable) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 30: OSPF Forwarding Address TLV Format Figure 37: OSPF Forwarding Address TLV Format
where: where:
Type is 289 Type is 287
Length is 4 for an IPv4 forwarding address an 16 for an IPv6 Length is 4 for an IPv4 forwarding address an 16 for an IPv6
forwarding address forwarding address
3.4. BGP Next Hop Information 3.4. BGP Next Hop Information
BGP link-state information for both IPv4 and IPv6 networks can be BGP link-state information for both IPv4 and IPv6 networks can be
carried over either an IPv4 BGP session, or an IPv6 BGP session. If carried over either an IPv4 BGP session, or an IPv6 BGP session. If
IPv4 BGP session is used, then the next hop in the MP_REACH_NLRI IPv4 BGP session is used, then the next hop in the MP_REACH_NLRI
SHOULD be an IPv4 address. Similarly, if IPv6 BGP session is used, SHOULD be an IPv4 address. Similarly, if IPv6 BGP session is used,
then the next hop in the MP_REACH_NLRI SHOULD be an IPv6 address. then the next hop in the MP_REACH_NLRI SHOULD be an IPv6 address.
Usually the next hop will be set to the local end-point address of Usually the next hop will be set to the local end-point address of
the BGP session. The next hop address MUST be encoded as described the BGP session. The next hop address MUST be encoded as described
in [RFC4760]. The length field of the next hop address will specify in [RFC4760]. The length field of the next hop address will specify
the next hop address-family. If the next hop length is 4, then the the next hop address-family. If the next hop length is 4, then the
next hop is an IPv4 address; if the next hop length is 16, then it is next hop is an IPv4 address; if the next hop length is 16, then it is
a global IPv6 address and if the next hop length is 32, then there is a global IPv6 address and if the next hop length is 32, then there is
one global IPv6 address followed by a link-local IPv6 address. The one global IPv6 address followed by a link-local IPv6 address. The
link-local IPv6 address should be used as described in [RFC2545]. link-local IPv6 address should be used as described in [RFC2545].
The BGP Next Hop attribute is used by each BGP-LS spaker to validate
the NLRI it receives. However, this specification doesn't mandate
any rule regarding the re-write of the BGP Next Hop attribute.
3.5. Inter-AS Links 3.5. Inter-AS Links
The main source of TE information is the IGP, which is not active on The main source of TE information is the IGP, which is not active on
inter-AS links. In order to inject a non-IGP enabled link into the inter-AS links. In order to inject a non-IGP enabled link into the
BGP link-state RIB an implementation must support configuration of BGP link-state RIB an implementation must support configuration of
static links. static links.
4. Link to Path Aggregation 4. Link to Path Aggregation
Distribution of all links available in the global Internet is Distribution of all links available in the global Internet is
skipping to change at page 27, line 45 skipping to change at page 34, line 7
of nodes. The "aggregate link" represents the aggregated set of link of nodes. The "aggregate link" represents the aggregated set of link
properties between a pair of non-adjacent nodes. The actual methods properties between a pair of non-adjacent nodes. The actual methods
to compute the path properties (of bandwidth, metric) are outside the to compute the path properties (of bandwidth, metric) are outside the
scope of this document. The decision whether to advertise all scope of this document. The decision whether to advertise all
specific links or aggregated links is an operator's policy choice. specific links or aggregated links is an operator's policy choice.
To highlight the varying levels of exposure, the following deployment To highlight the varying levels of exposure, the following deployment
examples shall be discussed. examples shall be discussed.
4.1. Example: No Link Aggregation 4.1. Example: No Link Aggregation
Consider Figure 31. Both AS1 and AS2 operators want to protect their Consider Figure 38. Both AS1 and AS2 operators want to protect their
inter-AS {R1,R3}, {R2, R4} links using RSVP-FRR LSPs. If R1 wants to inter-AS {R1,R3}, {R2, R4} links using RSVP-FRR LSPs. If R1 wants to
compute its link-protection LSP to R3 it needs to "see" an alternate compute its link-protection LSP to R3 it needs to "see" an alternate
path to R3. Therefore the AS2 operator exposes its topology. All path to R3. Therefore the AS2 operator exposes its topology. All
BGP TE enabled routers in AS1 "see" the full topology of AS and BGP TE enabled routers in AS1 "see" the full topology of AS and
therefore can compute a backup path. Note that the decision if the therefore can compute a backup path. Note that the decision if the
direct link between {R3, R4} or the {R4, R5, R3) path is used is made direct link between {R3, R4} or the {R4, R5, R3) path is used is made
by the computing router. by the computing router.
AS1 : AS2 AS1 : AS2
: :
R1-------R3 R1-------R3
| : | \ | : | \
| : | R5 | : | R5
| : | / | : | /
R2-------R4 R2-------R4
: :
: :
Figure 31: no-link-aggregation Figure 38: no-link-aggregation
4.2. Example: ASBR to ASBR Path Aggregation 4.2. Example: ASBR to ASBR Path Aggregation
The brief difference between the "no-link aggregation" example and The brief difference between the "no-link aggregation" example and
this example is that no specific link gets exposed. Consider this example is that no specific link gets exposed. Consider
Figure 32. The only link which gets advertised by AS2 is an Figure 39. The only link which gets advertised by AS2 is an
"aggregate" link between R3 and R4. This is enough to tell AS1 that "aggregate" link between R3 and R4. This is enough to tell AS1 that
there is a backup path. However the actual links being used are there is a backup path. However the actual links being used are
hidden from the topology. hidden from the topology.
AS1 : AS2 AS1 : AS2
: :
R1-------R3 R1-------R3
| : | | : |
| : | | : |
| : | | : |
R2-------R4 R2-------R4
: :
: :
Figure 32: asbr-link-aggregation Figure 39: asbr-link-aggregation
4.3. Example: Multi-AS Path Aggregation 4.3. Example: Multi-AS Path Aggregation
Service providers in control of multiple ASes may even decide to not Service providers in control of multiple ASes may even decide to not
expose their internal inter-AS links. Consider Figure 33. Rather expose their internal inter-AS links. Consider Figure 40. AS3 is
than exposing all specific R3 to R6 links, AS3 is modeled as a single modeled as a single node which connects to the border routers of the
node which connects to the border routers of the aggregated domain. aggregated domain.
AS1 : AS2 : AS3 AS1 : AS2 : AS3
: : : :
R1-------R3----- R1-------R3-----
| : : \ | : : \
| : : vR0 | : : vR0
| : : / | : : /
R2-------R4----- R2-------R4-----
: : : :
: : : :
Figure 33: multi-as-aggregation Figure 40: multi-as-aggregation
5. IANA Considerations 5. IANA Considerations
This document requests a code point from the registry of Address This document requests a code point from the registry of Address
Family Numbers. Family Numbers.
This document requests a code point from the BGP Path Attributes This document requests a code point from the BGP Path Attributes
registry. registry.
This document requests creation of a new registry for node anchor, This document requests creation of a new registry for node anchor,
link descriptor and link attribute TLVs. Values 0-255 are reserved. link descriptor and link attribute TLVs. Values 0-255 are reserved.
Values 256-65535 will be used for Codepoints. The registry will be Values 256-65535 will be used for Codepoints. The registry will be
initialized as shown in Table 2 and Table 3. Allocations within the initialized as shown in Table 2 and Table 4. Allocations within the
registry will require documentation of the proposed use of the registry will require documentation of the proposed use of the
allocated value and approval by the Designated Expert assigned by the allocated value and approval by the Designated Expert assigned by the
IESG (see [RFC5226]). IESG (see [RFC5226]).
Note to RFC Editor: this section may be removed on publication as an Note to RFC Editor: this section may be removed on publication as an
RFC. RFC.
6. Manageability Considerations 6. Manageability Considerations
This section is structured as recommended in [RFC5706]. This section is structured as recommended in [RFC5706].
skipping to change at page 29, line 41 skipping to change at page 36, line 4
IESG (see [RFC5226]). IESG (see [RFC5226]).
Note to RFC Editor: this section may be removed on publication as an Note to RFC Editor: this section may be removed on publication as an
RFC. RFC.
6. Manageability Considerations 6. Manageability Considerations
This section is structured as recommended in [RFC5706]. This section is structured as recommended in [RFC5706].
6.1. Operational Considerations 6.1. Operational Considerations
6.1.1. Operations 6.1.1. Operations
Existing BGP operation procedures apply. No new operation procedures Existing BGP operation procedures apply. No new operation procedures
are defined in this document. It shall be noted that the NLRI are defined in this document. It shall be noted that the NLRI
information present in this document purely carries application level information present in this document purely carries application level
data that have no immediate corresponding forwarding state impact. data that have no immediate corresponding forwarding state impact.
As such, any churn in reachability information has different impact As such, any churn in reachability information has different impact
than regular BGP update which needs to chaange forwarding state for than regular BGP update which needs to change forwarding state for an
an entire router. Furthermore it is anticipated that distribution of entire router. Furthermore it is anticipated that distribution of
this NLRI will be handled by dedicated route-reflectors providing a this NLRI will be handled by dedicated route-reflectors providing a
level of isolation and fault-containment between different NLRI level of isolation and fault-containment between different NLRI
types. types.
6.1.2. Installation and Initial Setup 6.1.2. Installation and Initial Setup
Configuration parameters defined in Section 6.2.3 SHOULD be Configuration parameters defined in Section 6.2.3 SHOULD be
initialized to the following default values: initialized to the following default values:
o The Link-State NLRI capability is turned off for all neighbors. o The Link-State NLRI capability is turned off for all neighbors.
skipping to change at page 31, line 24 skipping to change at page 37, line 32
An implementation SHOULD allow the operator to specify neighbors to An implementation SHOULD allow the operator to specify neighbors to
which Link-State NLRIs will be advertised and from which Link-State which Link-State NLRIs will be advertised and from which Link-State
NLRIs will be accepted. NLRIs will be accepted.
An implementation SHOULD allow the operator to specify the maximum An implementation SHOULD allow the operator to specify the maximum
rate at which Link State NLRIs will be advertised/withdrawn from rate at which Link State NLRIs will be advertised/withdrawn from
neighbors neighbors
An implementation SHOULD allow the operator to specify the maximum An implementation SHOULD allow the operator to specify the maximum
rate at which Link State NLRIs will be accepted from neighbors
An implementation SHOULD allow the operator to specify the maximum
number of Link State NLRIs stored in router's RIB. number of Link State NLRIs stored in router's RIB.
An implementation SHOULD allow the operator to create abstracted An implementation SHOULD allow the operator to create abstracted
topologies that are advertised to neighbors; Create different topologies that are advertised to neighbors; Create different
abstractions for different neighbors. abstractions for different neighbors.
An implementation SHOULD allow the operator to configure a pair of
ASN and BGP identifier per flooding set the node participates in.
6.2.4. Accounting Management 6.2.4. Accounting Management
Not Applicable. Not Applicable.
6.2.5. Performance Management 6.2.5. Performance Management
An implementation SHOULD provide the following statistics: An implementation SHOULD provide the following statistics:
o Total number of Link-State NLRI updates sent/received o Total number of Link-State NLRI updates sent/received
skipping to change at page 32, line 11 skipping to change at page 38, line 14
o Number of errored received Link-State NLRI updates, per neighbor o Number of errored received Link-State NLRI updates, per neighbor
o Total number of locally originated Link-State NLRIs o Total number of locally originated Link-State NLRIs
6.2.6. Security Management 6.2.6. Security Management
An operator SHOULD define ACLs to limit inbound updates as follows: An operator SHOULD define ACLs to limit inbound updates as follows:
o Drop all updates from Consumer peers o Drop all updates from Consumer peers
7. Security Considerations 7. TLV/SubTLV Code Points Summary
This section contains the global table of all TLVs/SubTLVs defined in
this document.
+------------+--------------------+---------------+-----------------+
| TLV/SubTLV | Description | IS-IS | Value defined |
| | | TLV/Sub-TLV | in: |
+------------+--------------------+---------------+-----------------+
| 256 | Identifier | -- | Section 3.2.1 |
| 257 | Local Node | -- | Section 3.2.2.1 |
| | Descriptors | | |
| 258 | Remote Node | -- | Section 3.2.2.2 |
| | Descriptors | | |
| 259 | Autonomous System | -- | Section 3.2.2.3 |
| 260 | BGP Identifier | -- | Section 3.2.2.3 |
| 261 | ISO Node-ID | -- | Section 3.2.2.3 |
| 262 | IPv4 Router-ID | -- | Section 3.2.2.3 |
| 263 | IPv6 Router-ID | -- | Section 3.2.2.3 |
| 264 | Link Local/Remote | 22/4 | [RFC5307]/1.1 |
| | Identifiers | | |
| 265 | IPv4 interface | 22/6 | [RFC5305]/3.2 |
| | address | | |
| 266 | IPv4 neighbor | 22/8 | [RFC5305]/3.3 |
| | address | | |
| 267 | IPv6 interface | 22/12 | [RFC6119]/4.2 |
| | address | | |
| 268 | IPv6 neighbor | 22/13 | [RFC6119]/4.3 |
| | address | | |
| 256/5 | Multi Topology ID | -- | Section 3.2.1.5 |
| 269 | Administrative | 22/3 | [RFC5305]/3.1 |
| | group (color) | | |
| 270 | Maximum link | 22/9 | [RFC5305]/3.3 |
| | bandwidth | | |
| 271 | Max. reservable | 22/10 | [RFC5305]/3.5 |
| | link bandwidth | | |
| 272 | Unreserved | 22/11 | [RFC5305]/3.6 |
| | bandwidth | | |
| 273 | TE Default Metric | 22/18 | [RFC5305]/3.7 |
| 274 | Link Protection | 22/20 | [RFC5307]/1.2 |
| | Type | | |
| 275 | MPLS Protocol Mask | -- | Section 3.3.1.1 |
| 276 | Metric | -- | Section 3.3.1.2 |
| 277 | Shared Risk Link | -- | Section 3.3.1.3 |
| | Group | | |
| 278 | OSPF specific link | -- | Section 3.3.1.4 |
| | attribute | | |
| 279 | IS-IS Specific | -- | Section 3.3.1.5 |
| | Link Attribute | | |
| 280 | Node Flag Bits | -- | Section 3.3.2.2 |
| 281 | OSPF Specific Node | -- | Section 3.3.2.3 |
| | Properties | | |
| 282 | IS-IS Specific | -- | Section 3.3.2.4 |
| | Node Properties | | |
| 283 | IGP Flags | -- | Section 3.3.3.1 |
| 284 | Route Tag | -- | [RFC5130] |
| 285 | Extended Tag | -- | [RFC5130] |
| 286 | Prefix Metric | -- | [RFC5305] |
| 287 | OSPF Forwarding | -- | [RFC2328] |
| | Address | | |
+------------+--------------------+---------------+-----------------+
Table 10: Summary Table of TLV/SubTLV Codepoints
8. Security Considerations
Procedures and protocol extensions defined in this document do not Procedures and protocol extensions defined in this document do not
affect the BGP security model. affect the BGP security model.
A BGP Speaker SHOULD NOT accept updates from a Consumer peer. A BGP Speaker SHOULD NOT accept updates from a Consumer peer.
An operator SHOULD employ a mechanism to protect a BGP Speaker An operator SHOULD employ a mechanism to protect a BGP Speaker
against DDOS attacks from Consumers. against DDOS attacks from Consumers.
8. Acknowledgements 9. Contributors
We would like to thank Nischal Sheth, Alia Atlas, Robert Varga, David We would like to thank Robert Varga for the significant contribution
Ward, Derek Yeung, Murtuza Lightwala, John Scudder, Kaliraj he gave to this document.
Vairavakkalai, Les Ginsberg, Liem Nguyen, Manish Bhardwaj, Mike
Shand, Peter Psenak, Rex Fernando, Richard Woundy, Saikat Ray, Steven
Luong, Tamas Mondal, Waqas Alam, and Yakov Rekhter for their
comments.
9. References 10. Acknowledgements
9.1. Normative References We would like to thank Nischal Sheth, Alia Atlas, David Ward, Derek
Yeung, Murtuza Lightwala, John Scudder, Kaliraj Vairavakkalai, Les
Ginsberg, Liem Nguyen, Manish Bhardwaj, Mike Shand, Peter Psenak, Rex
Fernando, Richard Woundy, Steven Luong, Tamas Mondal, Waqas Alam,
Vipin Kumar, Naiming Shen and Yakov Rekhter for their comments.
11. References
11.1. Normative References
[RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and
dual environments", RFC 1195, December 1990. dual environments", RFC 1195, December 1990.
[RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and [RFC1918] Rekhter, Y., Moskowitz, R., Karrenberg, D., Groot, G., and
E. Lear, "Address Allocation for Private Internets", E. Lear, "Address Allocation for Private Internets",
BCP 5, RFC 1918, February 1996. BCP 5, RFC 1918, February 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
skipping to change at page 33, line 20 skipping to change at page 41, line 30
Support of Generalized Multi-Protocol Label Switching Support of Generalized Multi-Protocol Label Switching
(GMPLS)", RFC 4202, October 2005. (GMPLS)", RFC 4202, October 2005.
[RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway
Protocol 4 (BGP-4)", RFC 4271, January 2006. Protocol 4 (BGP-4)", RFC 4271, January 2006.
[RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter, [RFC4760] Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
"Multiprotocol Extensions for BGP-4", RFC 4760, "Multiprotocol Extensions for BGP-4", RFC 4760,
January 2007. January 2007.
[RFC4893] Vohra, Q. and E. Chen, "BGP Support for Four-octet AS
Number Space", RFC 4893, May 2007.
[RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P. [RFC4915] Psenak, P., Mirtorabi, S., Roy, A., Nguyen, L., and P.
Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF",
RFC 4915, June 2007. RFC 4915, June 2007.
[RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP [RFC5036] Andersson, L., Minei, I., and B. Thomas, "LDP
Specification", RFC 5036, October 2007. Specification", RFC 5036, October 2007.
[RFC5065] Traina, P., McPherson, D., and J. Scudder, "Autonomous
System Confederations for BGP", RFC 5065, August 2007.
[RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi [RFC5120] Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
Topology (MT) Routing in Intermediate System to Topology (MT) Routing in Intermediate System to
Intermediate Systems (IS-ISs)", RFC 5120, February 2008. Intermediate Systems (IS-ISs)", RFC 5120, February 2008.
[RFC5130] Previdi, S., Shand, M., and C. Martin, "A Policy Control [RFC5130] Previdi, S., Shand, M., and C. Martin, "A Policy Control
Mechanism in IS-IS Using Administrative Tags", RFC 5130, Mechanism in IS-IS Using Administrative Tags", RFC 5130,
February 2008. February 2008.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
skipping to change at page 34, line 6 skipping to change at page 42, line 12
[RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic
Engineering", RFC 5305, October 2008. Engineering", RFC 5305, October 2008.
[RFC5307] Kompella, K. and Y. Rekhter, "IS-IS Extensions in Support [RFC5307] Kompella, K. and Y. Rekhter, "IS-IS Extensions in Support
of Generalized Multi-Protocol Label Switching (GMPLS)", of Generalized Multi-Protocol Label Switching (GMPLS)",
RFC 5307, October 2008. RFC 5307, October 2008.
[RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic [RFC6119] Harrison, J., Berger, J., and M. Bartlett, "IPv6 Traffic
Engineering in IS-IS", RFC 6119, February 2011. Engineering in IS-IS", RFC 6119, February 2011.
9.2. Informative References [RFC6822] Previdi, S., Ginsberg, L., Shand, M., Roy, A., and D.
Ward, "IS-IS Multi-Instance", RFC 6822, December 2012.
11.2. Informative References
[I-D.ietf-alto-protocol] [I-D.ietf-alto-protocol]
Alimi, R., Penno, R., and Y. Yang, "ALTO Protocol", Alimi, R., Penno, R., and Y. Yang, "ALTO Protocol",
draft-ietf-alto-protocol-13 (work in progress), draft-ietf-alto-protocol-13 (work in progress),
September 2012. September 2012.
[I-D.ietf-isis-mi]
Previdi, S., Ginsberg, L., Shand, M., Roy, A., and D.
Ward, "IS-IS Multi-Instance", draft-ietf-isis-mi-08 (work
in progress), October 2012.
[RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation [RFC4655] Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
Element (PCE)-Based Architecture", RFC 4655, August 2006. Element (PCE)-Based Architecture", RFC 4655, August 2006.
[RFC4970] Lindem, A., Shen, N., Vasseur, JP., Aggarwal, R., and S. [RFC4970] Lindem, A., Shen, N., Vasseur, JP., Aggarwal, R., and S.
Shaffer, "Extensions to OSPF for Advertising Optional Shaffer, "Extensions to OSPF for Advertising Optional
Router Capabilities", RFC 4970, July 2007. Router Capabilities", RFC 4970, July 2007.
[RFC5073] Vasseur, J. and J. Le Roux, "IGP Routing Protocol [RFC5073] Vasseur, J. and J. Le Roux, "IGP Routing Protocol
Extensions for Discovery of Traffic Engineering Node Extensions for Discovery of Traffic Engineering Node
Capabilities", RFC 5073, December 2007. Capabilities", RFC 5073, December 2007.
skipping to change at page 34, line 42 skipping to change at page 42, line 46
RFC 5152, February 2008. RFC 5152, February 2008.
[RFC5693] Seedorf, J. and E. Burger, "Application-Layer Traffic [RFC5693] Seedorf, J. and E. Burger, "Application-Layer Traffic
Optimization (ALTO) Problem Statement", RFC 5693, Optimization (ALTO) Problem Statement", RFC 5693,
October 2009. October 2009.
[RFC5706] Harrington, D., "Guidelines for Considering Operations and [RFC5706] Harrington, D., "Guidelines for Considering Operations and
Management of New Protocols and Protocol Extensions", Management of New Protocols and Protocol Extensions",
RFC 5706, November 2009. RFC 5706, November 2009.
[RFC6286] Chen, E. and J. Yuan, "Autonomous-System-Wide Unique BGP
Identifier for BGP-4", RFC 6286, June 2011.
[RFC6549] Lindem, A., Roy, A., and S. Mirtorabi, "OSPFv2 Multi- [RFC6549] Lindem, A., Roy, A., and S. Mirtorabi, "OSPFv2 Multi-
Instance Extensions", RFC 6549, March 2012. Instance Extensions", RFC 6549, March 2012.
Authors' Addresses Authors' Addresses
Hannes Gredler Hannes Gredler
Juniper Networks, Inc. Juniper Networks, Inc.
1194 N. Mathilda Ave. 1194 N. Mathilda Ave.
Sunnyvale, CA 94089 Sunnyvale, CA 94089
US US
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