draft-ietf-idr-ls-distribution-05.txt   draft-ietf-idr-ls-distribution-06.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: November 20, 2014 S. Previdi Expires: March 20, 2015 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.
May 21, 2014 September 16, 2014
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-05 draft-ietf-idr-ls-distribution-06
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
engineering information can be collected from networks and shared engineering information can be collected from networks and shared
with external components using the BGP routing protocol. This is with external components using the BGP routing protocol. This is
achieved using a new BGP Network Layer Reachability Information achieved using a new BGP Network Layer Reachability Information
(NLRI) encoding format. The mechanism is applicable to physical and (NLRI) encoding format. The mechanism is applicable to physical and
virtual IGP links. The mechanism described is subject to policy virtual IGP links. The mechanism described is subject to policy
control. control.
Applications of this technique include Application Layer Traffic Applications of this technique include Application Layer Traffic
Optimization (ALTO) servers, and Path Computation Elements (PCEs). Optimization (ALTO) servers, and Path Computation Elements (PCEs).
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119]. document are to be interpreted as described in RFC 2119 [RFC2119].
Status of this Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
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 November 20, 2014. This Internet-Draft will expire on March 20, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
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 . . . . . . . . . . . . . . . . . 6 2.2. ALTO Server Network API . . . . . . . . . . . . . . . . . 6
3. Carrying Link State Information in BGP . . . . . . . . . . . . 7 3. Carrying Link State Information in BGP . . . . . . . . . . . 7
3.1. TLV Format . . . . . . . . . . . . . . . . . . . . . . . . 7 3.1. TLV Format . . . . . . . . . . . . . . . . . . . . . . . 8
3.2. The Link-State NLRI . . . . . . . . . . . . . . . . . . . 8 3.2. The Link-State NLRI . . . . . . . . . . . . . . . . . . . 8
3.2.1. Node Descriptors . . . . . . . . . . . . . . . . . . . 11 3.2.1. Node Descriptors . . . . . . . . . . . . . . . . . . 12
3.2.1.1. Globally Unique Node/Link/Prefix Identifiers . . . 11 3.2.2. Link Descriptors . . . . . . . . . . . . . . . . . . 16
3.2.1.2. Local Node Descriptors . . . . . . . . . . . . . . 12 3.2.3. Prefix Descriptors . . . . . . . . . . . . . . . . . 17
3.2.1.3. Remote Node Descriptors . . . . . . . . . . . . . 12 3.3. The BGP-LS Attribute . . . . . . . . . . . . . . . . . . 19
3.2.1.4. Node Descriptor Sub-TLVs . . . . . . . . . . . . . 13 3.3.1. Node Attribute TLVs . . . . . . . . . . . . . . . . . 19
3.2.1.5. Multi-Topology ID . . . . . . . . . . . . . . . . 14 3.3.2. Link Attribute TLVs . . . . . . . . . . . . . . . . . 22
3.2.2. Link Descriptors . . . . . . . . . . . . . . . . . . . 15 3.3.3. Prefix Attribute TLVs . . . . . . . . . . . . . . . . 27
3.2.3. Prefix Descriptors . . . . . . . . . . . . . . . . . . 16 3.4. BGP Next Hop Information . . . . . . . . . . . . . . . . 30
3.2.3.1. OSPF Route Type . . . . . . . . . . . . . . . . . 16 3.5. Inter-AS Links . . . . . . . . . . . . . . . . . . . . . 31
3.2.3.2. IP Reachability Information . . . . . . . . . . . 17 3.6. Router-ID Anchoring Example: ISO Pseudonode . . . . . . . 31
3.3. The BGP-LS Attribute . . . . . . . . . . . . . . . . . . . 17 3.7. Router-ID Anchoring Example: OSPF Pseudonode . . . . . . 32
3.3.1. Node Attribute TLVs . . . . . . . . . . . . . . . . . 17 3.8. Router-ID Anchoring Example: OSPFv2 to IS-IS Migration . 33
3.3.1.1. Node Flag Bits TLV . . . . . . . . . . . . . . . . 18 4. Link to Path Aggregation . . . . . . . . . . . . . . . . . . 33
3.3.1.2. IS-IS Area Identifier TLV . . . . . . . . . . . . 18 4.1. Example: No Link Aggregation . . . . . . . . . . . . . . 34
3.3.1.3. Node Name TLV . . . . . . . . . . . . . . . . . . 19 4.2. Example: ASBR to ASBR Path Aggregation . . . . . . . . . 34
3.3.1.4. Local IPv4/IPv6 Router-ID . . . . . . . . . . . . 19 4.3. Example: Multi-AS Path Aggregation . . . . . . . . . . . 35
3.3.1.5. Opaque Node Attribute TLV . . . . . . . . . . . . 19 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 35
3.3.2. Link Attribute TLVs . . . . . . . . . . . . . . . . . 20 6. Manageability Considerations . . . . . . . . . . . . . . . . 36
3.3.2.1. IPv4/IPv6 Router-ID . . . . . . . . . . . . . . . 21 6.1. Operational Considerations . . . . . . . . . . . . . . . 36
3.3.2.2. MPLS Protocol Mask TLV . . . . . . . . . . . . . . 21 6.1.1. Operations . . . . . . . . . . . . . . . . . . . . . 36
3.3.2.3. TE Default Metric TLV . . . . . . . . . . . . . . 22 6.1.2. Installation and Initial Setup . . . . . . . . . . . 36
3.3.2.4. IGP Metric TLV . . . . . . . . . . . . . . . . . . 22 6.1.3. Migration Path . . . . . . . . . . . . . . . . . . . 36
3.3.2.5. Shared Risk Link Group TLV . . . . . . . . . . . . 22 6.1.4. Requirements on Other Protocols and Functional
3.3.2.6. Opaque Link Attribute TLV . . . . . . . . . . . . 23 Components . . . . . . . . . . . . . . . . . . . . . 37
3.3.2.7. Link Name TLV . . . . . . . . . . . . . . . . . . 23 6.1.5. Impact on Network Operation . . . . . . . . . . . . . 37
3.3.3. Prefix Attribute TLVs . . . . . . . . . . . . . . . . 24 6.1.6. Verifying Correct Operation . . . . . . . . . . . . . 37
3.3.3.1. IGP Flags TLV . . . . . . . . . . . . . . . . . . 24 6.2. Management Considerations . . . . . . . . . . . . . . . . 37
3.3.3.2. Route Tag . . . . . . . . . . . . . . . . . . . . 25 6.2.1. Management Information . . . . . . . . . . . . . . . 37
3.3.3.3. Extended Route Tag . . . . . . . . . . . . . . . . 25 6.2.2. Fault Management . . . . . . . . . . . . . . . . . . 37
3.3.3.4. Prefix Metric TLV . . . . . . . . . . . . . . . . 26 6.2.3. Configuration Management . . . . . . . . . . . . . . 37
3.3.3.5. OSPF Forwarding Address TLV . . . . . . . . . . . 26 6.2.4. Accounting Management . . . . . . . . . . . . . . . . 38
3.3.3.6. Opaque Prefix Attribute TLV . . . . . . . . . . . 26 6.2.5. Performance Management . . . . . . . . . . . . . . . 38
3.4. BGP Next Hop Information . . . . . . . . . . . . . . . . . 27 6.2.6. Security Management . . . . . . . . . . . . . . . . . 38
3.5. Inter-AS Links . . . . . . . . . . . . . . . . . . . . . . 27 7. TLV/Sub-TLV Code Points Summary . . . . . . . . . . . . . . . 38
3.6. Router-ID Anchoring Example: ISO Pseudonode . . . . . . . 27 8. Security Considerations . . . . . . . . . . . . . . . . . . . 40
3.7. Router-ID Anchoring Example: OSPFv2 to IS-IS Migration . . 28 9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 41
4. Link to Path Aggregation . . . . . . . . . . . . . . . . . . . 28 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 41
4.1. Example: No Link Aggregation . . . . . . . . . . . . . . . 29 11. References . . . . . . . . . . . . . . . . . . . . . . . . . 41
4.2. Example: ASBR to ASBR Path Aggregation . . . . . . . . . . 29 11.1. Normative References . . . . . . . . . . . . . . . . . . 41
4.3. Example: Multi-AS Path Aggregation . . . . . . . . . . . . 29 11.2. Informative References . . . . . . . . . . . . . . . . . 43
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 44
6. Manageability Considerations . . . . . . . . . . . . . . . . . 30
6.1. Operational Considerations . . . . . . . . . . . . . . . . 30
6.1.1. Operations . . . . . . . . . . . . . . . . . . . . . . 30
6.1.2. Installation and Initial Setup . . . . . . . . . . . . 30
6.1.3. Migration Path . . . . . . . . . . . . . . . . . . . . 31
6.1.4. Requirements on Other Protocols and Functional Component 31
6.1.5. Impact on Network Operation . . . . . . . . . . . . . 31
6.1.6. Verifying Correct Operation . . . . . . . . . . . . . 31
6.2. Management Considerations . . . . . . . . . . . . . . . . 31
6.2.1. Management Information . . . . . . . . . . . . . . . . 31
6.2.2. Fault Management . . . . . . . . . . . . . . . . . . . 31
6.2.3. Configuration Management . . . . . . . . . . . . . . . 31
6.2.4. Accounting Management . . . . . . . . . . . . . . . . 32
6.2.5. Performance Management . . . . . . . . . . . . . . . . 32
6.2.6. Security Management . . . . . . . . . . . . . . . . . 32
7. TLV/Sub-TLV Code Points Summary . . . . . . . . . . . . . . . 32
8. Security Considerations . . . . . . . . . . . . . . . . . . . 34
9. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 34
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 34
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 35
11.1. Normative References . . . . . . . . . . . . . . . . . . 35
11.2. Informative References . . . . . . . . . . . . . . . . . 36
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 37
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
skipping to change at page 4, line 26 skipping to change at page 4, line 17
components using the BGP routing protocol [RFC4271]. This is components using the BGP routing protocol [RFC4271]. This is
achieved using a new BGP Network Layer Reachability Information achieved using a new BGP Network Layer Reachability Information
(NLRI) encoding format. The mechanism is applicable to physical and (NLRI) encoding format. The mechanism is applicable to physical and
virtual links. The mechanism described is subject to policy control. virtual links. The mechanism described is subject to policy control.
A router maintains one or more databases for storing link-state A router maintains one or more databases for storing link-state
information about nodes and links in any given area. Link attributes information about nodes and links in any given area. Link attributes
stored in these databases include: local/remote IP addresses, local/ stored in these databases include: local/remote IP addresses, local/
remote interface identifiers, link metric and TE metric, link remote interface identifiers, link metric and TE metric, link
bandwidth, reservable bandwidth, per CoS class reservation state, bandwidth, reservable bandwidth, per CoS class reservation state,
preemption and Shared Risk Link Groups (SRLG). The router's BGP preemption and Shared Risk Link Groups (SRLG). The router's BGP
process can retrieve topology from these LSDBs and distribute it to a process can retrieve topology from these LSDBs and distribute it to a
consumer, either directly or via a peer BGP Speaker (typically a consumer, either directly or via a peer BGP Speaker (typically a
dedicated Route Reflector), using the encoding specified in this dedicated Route Reflector), using the encoding specified in this
document. document.
The collection of Link State and TE link state information and its The collection of Link State and TE link state information and its
distribution to consumers is shown in the following figure. distribution to consumers is shown in the following figure.
+-----------+ +-----------+
| Consumer | | Consumer |
+-----------+ +-----------+
^ ^
| |
+-----------+ +-----------+
| BGP | +-----------+ | BGP | +-----------+
| Speaker | | Consumer | | Speaker | | Consumer |
+-----------+ +-----------+ +-----------+ +-----------+
^ ^ ^ ^ ^ ^ ^ ^
| | | | | | | |
+---------------+ | +-------------------+ | +---------------+ | +-------------------+ |
| | | | | | | |
+-----------+ +-----------+ +-----------+ +-----------+ +-----------+ +-----------+
| BGP | | BGP | | BGP | | BGP | | BGP | | BGP |
| Speaker | | Speaker | . . . | Speaker | | Speaker | | Speaker | . . . | Speaker |
+-----------+ +-----------+ +-----------+ +-----------+ +-----------+ +-----------+
^ ^ ^ ^ ^ ^
| | | | | |
IGP IGP IGP IGP IGP IGP
Figure 1: TE Link State info collection
A BGP Speaker may apply configurable policy to the information that A BGP Speaker may apply configurable policy to the information that
it distributes. Thus, it may distribute the real physical topology it distributes. Thus, it may distribute the real physical topology
from the LSDB or the TED. Alternatively, it may create an abstracted from the LSDB or the TED. Alternatively, it may create an abstracted
topology, where virtual, aggregated nodes are connected by virtual topology, where virtual, aggregated nodes are connected by virtual
paths. Aggregated nodes can be created, for example, out of multiple paths. Aggregated nodes can be created, for example, out of multiple
routers in a POP. Abstracted topology can also be a mix of physical routers in a POP. Abstracted topology can also be a mix of physical
and virtual nodes and physical and virtual links. Furthermore, the and virtual nodes and physical and virtual links. Furthermore, the
BGP Speaker can apply policy to determine when information is updated BGP Speaker can apply policy to determine when information is updated
to the consumer so that there is reduction of information flow form to the consumer so that there is reduction of information flow from
the network to the consumers. Mechanisms through which topologies the network to the consumers. Mechanisms through which topologies
can be aggregated or virtualized are outside the scope of this can be aggregated or virtualized are outside the scope of this
document document
2. Motivation and Applicability 2. Motivation and Applicability
This section describes use cases from which the requirements can be This section describes use cases from which the requirements can be
derived. derived.
2.1. MPLS-TE with PCE 2.1. MPLS-TE with PCE
As described in [RFC4655] a PCE can be used to compute MPLS-TE paths As described in [RFC4655] a PCE can be used to compute MPLS-TE paths
within a "domain" (such as an IGP area) or across multiple domains within a "domain" (such as an IGP area) or across multiple domains
(such as a multi-area AS, or multiple ASes). (such as a multi-area AS, or multiple ASes).
o Within a single area, the PCE offers enhanced computational power o Within a single area, the PCE offers enhanced computational power
that may not be available on individual routers, sophisticated that may not be available on individual routers, sophisticated
policy control and algorithms, and coordination of computation policy control and algorithms, and coordination of computation
across the whole area. across the whole area.
o If a router wants to compute a MPLS-TE path across IGP areas its o If a router wants to compute a MPLS-TE path across IGP areas, then
own TED lacks visibility of the complete topology. That means its own TED lacks visibility of the complete topology. That means
that the router cannot determine the end-to-end path, and cannot that the router cannot determine the end-to-end path, and cannot
even select the right exit router (Area Border Router - ABR) for even select the right exit router (Area Border Router - ABR) for
an optimal path. This is an issue for large-scale networks that an optimal path. This is an issue for large-scale networks that
need to segment their core networks into distinct areas, but which need to segment their core networks into distinct areas, but still
still want to take advantage of MPLS-TE. want to take advantage of MPLS-TE.
Previous solutions used per-domain path computation [RFC5152]. The Previous solutions used per-domain path computation [RFC5152]. The
source router could only compute the path for the first area because source router could only compute the path for the first area because
the router only has full topological visibility for the first area the router only has full topological visibility for the first area
along the path, but not for subsequent areas. Per-domain path along the path, but not for subsequent areas. Per-domain path
computation uses a technique called "loose-hop-expansion" [RFC3209], computation uses a technique called "loose-hop-expansion" [RFC3209],
and selects the exit ABR and other ABRs or AS Border Routers (ASBRs) and selects the exit ABR and other ABRs or AS Border Routers (ASBRs)
using the IGP computed shortest path topology for the remainder of using the IGP computed shortest path topology for the remainder of
the path. This may lead to sub-optimal paths, makes alternate/back- the path. This may lead to sub-optimal paths, makes alternate/back-
up path computation hard, and might result in no TE path being found up path computation hard, and might result in no TE path being found
skipping to change at page 6, line 18 skipping to change at page 6, line 13
to the TED for the area(s) it serves, but [RFC4655] does not describe to the TED for the area(s) it serves, but [RFC4655] does not describe
how this is achieved. Many implementations make the PCE a passive how this is achieved. Many implementations make the PCE a passive
participant in the IGP so that it can learn the latest state of the participant in the IGP so that it can learn the latest state of the
network, but this may be sub-optimal when the network is subject to a network, but this may be sub-optimal when the network is subject to a
high degree of churn, or when the PCE is responsible for multiple high degree of churn, or when the PCE is responsible for multiple
areas. areas.
The following figure shows how a PCE can get its TED information The following figure shows how a PCE can get its TED information
using the mechanism described in this document. using the mechanism described in this document.
+----------+ +---------+ +----------+ +---------+
| ----- | | BGP | | ----- | | BGP |
| | TED |<-+-------------------------->| Speaker | | | TED |<-+-------------------------->| Speaker |
| ----- | TED synchronization | | | ----- | TED synchronization | |
| | | mechanism: +---------+ | | | mechanism: +---------+
| | | BGP with Link-State NLRI | | | BGP with Link-State NLRI
| v | | v |
| ----- | | ----- |
| | PCE | | | | PCE | |
| ----- | | ----- |
+----------+ +----------+
^ ^
| Request/ | Request/
| Response | Response
v v
Service +----------+ Signaling +----------+ Service +----------+ Signaling +----------+
Request | Head-End | Protocol | Adjacent | Request | Head-End | Protocol | Adjacent |
-------->| Node |<------------>| Node | -------->| Node |<------------>| Node |
+----------+ +----------+ +----------+ +----------+
Figure 2: External PCE node using a TED synchronization mechanism
The mechanism in this document allows the necessary TED information The mechanism in this document allows the necessary TED information
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
Partition Identifiers (PIDs), and a Cost Map that specifies the cost Partition Identifiers (PIDs), and a Cost Map that specifies the cost
between PIDs listed in the Network Map. For more details, see [I-D between PIDs listed in the Network Map. For more details, see
.ietf-alto-protocol]. [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
underlying network. Note an ALTO Server can use other mechanisms to underlying network. Note an ALTO Server can use other mechanisms to
get network data, for example, peering with multiple IGP and BGP get network data, for example, peering with multiple IGP and BGP
Speakers. Speakers.
The following figure shows how an ALTO Server can get network The following figure shows how an ALTO Server can get network
topology information from the underlying network using the mechanism topology information from the underlying network using the mechanism
described in this document. described in this document.
+--------+ +--------+
| Client |<--+ | Client |<--+
+--------+ | +--------+ |
| ALTO +--------+ BGP with +---------+ | ALTO +--------+ BGP with +---------+
+--------+ | Protocol | ALTO | Link-State NLRI | BGP | +--------+ | Protocol | ALTO | Link-State NLRI | BGP |
| Client |<--+------------| Server |<----------------| Speaker | | Client |<--+------------| Server |<----------------| Speaker |
+--------+ | | | | | +--------+ | | | | |
| +--------+ +---------+ | +--------+ +---------+
+--------+ | +--------+ |
| Client |<--+ | Client |<--+
+--------+ +--------+
Figure 3: ALTO Server using network topology information
3. Carrying Link State Information in BGP 3. Carrying Link State Information in BGP
This specification contains two parts: definition of a new BGP NLRI This specification contains two parts: definition of a new BGP NLRI
that describes links, nodes and prefixes comprising IGP link state that describes links, nodes and prefixes comprising IGP link state
information, and definition of a new BGP path attribute (BGP-LS information, and definition of a new BGP path attribute (BGP-LS
attribute) that carries link, node and prefix properties and attribute) that carries link, node and prefix properties and
attributes, such as the link and prefix metric or auxiliary Router- attributes, such as the link and prefix metric or auxiliary Router-
IDs of nodes, etc. IDs of nodes, etc.
It is desired to keep the dependencies on the protocol source of this
attributes to a minimum and represent any content in an IGP neutral
way, such that applications which do want to learn about a Link-state
topology do not need to know about any OSPF or IS-IS protocol
specifics.
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
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
preserved and propagated. In order to compare NLRIs with unknown preserved and propagated. In order to compare NLRIs with unknown
TLVs all TLVs MUST be ordered in ascending order. If there are more TLVs all TLVs MUST be ordered in ascending order by TLV Type. If
TLVs of the same type, then the TLVs MUST be ordered in ascending there are more TLVs of the same type, then the TLVs MUST be ordered
order of the TLV value within the set of TLVs with the same type. in ascending order of the TLV value within the TLVs with the same
All TLVs that are not specified as mandatory are considered optional. type. All TLVs that are not specified as mandatory are considered
optional.
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
node, a link or a prefix. node, a link or a prefix.
All non-VPN link, node and prefix information SHALL be encoded using All non-VPN link, node and prefix information SHALL be encoded using
AFI 16388 / SAFI 71. VPN link, node and prefix information SHALL be AFI 16388 / SAFI 71. VPN link, node and prefix information SHALL be
encoded using AFI 16388 / SAFI 128. encoded using AFI 16388 / SAFI 128.
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 16388 / SAFI 71 and AFI 16388 / SAFI 128 for the VPN flavor. an AFI 16388 / SAFI 71 and AFI 16388 / SAFI 128 for the VPN flavor.
The format of the Link-State NLRI is shown in the following figure. The format of the Link-State NLRI 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NLRI Type | Total NLRI Length | | NLRI Type | Total NLRI Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
// Link-State NLRI (variable) // // Link-State NLRI (variable) //
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NLRI Type | Total NLRI Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Route Distinguisher +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Link-State NLRI (variable) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The 'Total NLRI Length' field contains the cumulative length, in Figure 5: Link-State AFI 16388 / SAFI 71 NLRI Format
octets, of rest of the NLRI not including the NLRI Type field or
itself. For VPN applications it also includes the length of the
Route Distinguisher.
The 'NLRI Type' field can contain one of the following values: 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| NLRI Type | Total NLRI Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Route Distinguisher +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
// Link-State NLRI (variable) //
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type = 1: Node NLRI Figure 6: Link-State VPN AFI 16388 / SAFI 128 NLRI Format
Type = 2: Link NLRI The 'Total NLRI Length' field contains the cumulative length, in
octets, of rest of the NLRI not including the NLRI Type field or
itself. For VPN applications, it also includes the length of the
Route Distinguisher.
Type = 3: IPv4 Topology Prefix NLRI +------+---------------------------+
| Type | NLRI Type |
+------+---------------------------+
| 1 | Node NLRI |
| 2 | Link NLRI |
| 3 | IPv4 Topology Prefix NLRI |
| 4 | IPv6 Topology Prefix NLRI |
+------+---------------------------+
Type = 4: IPv6 Topology Prefix NLRI Table 1: NLRI Types
The Node NLRI (NLRI Type = 1) is shown in the following figure. The Node 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 | | Protocol-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identifier | | Identifier |
| (64 bits) | | (64 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Local Node Descriptors (variable) // // Local Node Descriptors (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 7: The Node NLRI format
The Link NLRI (NLRI Type = 2) is shown in the following figure. The Link 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 | | Protocol-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identifier | | Identifier |
| (64 bits) | | (64 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Local Node Descriptors (variable) // // Local Node Descriptors (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Remote Node Descriptors (variable) // // Remote Node Descriptors (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Link Descriptors (variable) // // Link Descriptors (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 8: The Link 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 | | Protocol-ID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Identifier | | Identifier |
| (64 bits) | | (64 bits) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Local Node Descriptor (variable) // // Local Node Descriptor (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Prefix Descriptors (variable) // // Prefix Descriptors (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The 'Protocol-ID' field can contain one of the following values:
Protocol-ID = 0: Unknown, The source of NLRI information could not
be determined
Protocol-ID = 1: IS-IS Level 1, The NLRI information has been
sourced by IS-IS Level 1
Protocol-ID = 2: IS-IS Level 2, The NLRI information has been Figure 9: The IPv4/IPv6 Topology Prefix NLRI format
sourced by IS-IS Level 2
Protocol-ID = 3: OSPF, The NLRI information has been sourced by The 'Protocol-ID' field can contain one of the following values:
OSPF
Protocol-ID = 4: Direct, The NLRI information has been sourced +-------------+----------------------------------+
from local interface state | Protocol-ID | NLRI information source protocol |
+-------------+----------------------------------+
| 1 | IS-IS Level 1 |
| 2 | IS-IS Level 2 |
| 3 | OSPFv2 |
| 4 | Direct |
| 5 | Static configuration |
| 6 | OSPFv3 |
+-------------+----------------------------------+
Protocol-ID = 5: Static, The NLRI information has been sourced by Table 2: Protocol Identifiers
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 [RFC6822] and [RFC6549]. These instances define the same link. See [RFC6822] and [RFC6549]. These instances define
independent "routing universes". The 64-Bit 'Identifier' field is independent "routing universes". The 64-Bit 'Identifier' field is
used to identify the "routing universe" where the NLRI belongs. The used to identify the "routing universe" where the NLRI belongs. The
NLRIs representing IGP objects (nodes, links or prefixes) from the NLRIs representing IGP objects (nodes, links or prefixes) from the
same routing universe MUST have the same 'Identifier' value; NLRIs same routing universe MUST have the same 'Identifier' value; NLRIs
with different 'Identifier' values MUST be considered to be from with different 'Identifier' values MUST be considered to be from
different routing universes. Table Table 1 lists the 'Identifier' different routing universes. Table Table 3 lists the 'Identifier'
values that are defined as well-known in this draft. values that are defined as well-known in this draft.
+------------+---------------------+ +------------+---------------------+
| Identifier | Routing Universe | | Identifier | Routing Universe |
+------------+---------------------+ +------------+---------------------+
| 0 | L3 packet topology | | 0 | L3 packet topology |
| 1 | L1 optical topology | | 1 | L1 optical topology |
+------------+---------------------+ +------------+---------------------+
Table 3: Well-known Instance Identifiers
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. described in the following sections.
3.2.1. Node Descriptors 3.2.1. Node Descriptors
Each link is anchored by a pair of Router-IDs that are used by the Each link is anchored by a pair of Router-IDs that are used by the
underlying IGP, namely, 48 Bit ISO System-ID for IS-IS and 32 bit underlying IGP, namely, 48 Bit ISO System-ID for IS-IS and 32 bit
Router-ID for OSPFv2 and OSPFv3. An IGP may use one or more Router-ID for OSPFv2 and OSPFv3. An IGP may use one or more
additional auxiliary Router-IDs, mainly for traffic engineering additional auxiliary Router-IDs, mainly for traffic engineering
purposes. For example, IS-IS may have one or more IPv4 and IPv6 TE purposes. For example, IS-IS may have one or more IPv4 and IPv6 TE
Router-IDs [RFC5305], [RFC6119]. These auxiliary Router-IDs MUST be Router-IDs [RFC5305], [RFC6119]. These auxiliary Router-IDs MUST be
included in the link attribute described in Section Section 3.3.2. included in the link attribute described in Section Section 3.3.2.
It is desirable that the Router-ID assignments inside the Node It is desirable that the Router-ID assignments inside the Node
Descriptor are globally unique. However there may be Router-ID Descriptor are globally unique. However there may be Router-ID
spaces (e.g. ISO) where no global registry exists, or worse, Router- spaces (e.g. ISO) where no global registry exists, or worse, Router-
IDs have been allocated following private-IP RFC 1918 [RFC1918] IDs have been allocated following private-IP RFC 1918 [RFC1918]
allocation. We use Autonomous System (AS) Number and BGP-LS allocation. We use Autonomous System (AS) Number and BGP-LS
Identifier in order to disambiguate the Router-IDs, as described in Identifier (Paragraph 2) in order to disambiguate the Router-IDs, as
Section 3.2.1.1. described in Section 3.2.1.1.
3.2.1.1. Globally Unique Node/Link/Prefix Identifiers 3.2.1.1. Globally Unique Node/Link/Prefix Identifiers
One problem that needs to be addressed is the ability to identify an 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 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 collected by all BGP-LS speakers that talk to each other). This can
be expressed through the following two requirements: be expressed through the following two requirements:
(A) The same node must not be represented by two keys (otherwise one (A) The same node must not be represented by two keys (otherwise one
node will look like two nodes). node will look like two nodes).
(B) Two different nodes must not be represented by the same key (B) Two different nodes must not be represented by the same key
(otherwise, two nodes will look like one node). (otherwise, two nodes will look like one node).
We define an "IGP domain" to be the set of nodes (hence, by extension We define an "IGP domain" to be the set of nodes (hence, by extension
links and prefixes), within which, each node has a unique IGP links and prefixes), within which, each node has a unique IGP
representation by using the combination of Area-ID, Router-ID, representation by using the combination of Area-ID, Router-ID,
Protocol, Topology-ID, and Instance ID. The problem is that BGP may Protocol, Topology-ID, and Instance ID. The problem is that BGP may
receive node/link/prefix information from multiple independent "IGP receive node/link/prefix information from multiple independent "IGP
domains" and we need to distinguish between them. Moreover, we can't domains" and we need to distinguish between them. Moreover, we can't
assume there is always one and only one IGP domain per AS. During IGP assume there is always one and only one IGP domain per AS. During
transitions it may happen that two redundant IGPs are in place. IGP transitions it may happen that two redundant IGPs are in place.
In section Section 3.2.1.4 a set of sub-TLVs is described, which In section Section 3.2.1.4 a set of sub-TLVs is described, which
allows to specify a flexible key for any given Node/Link information allows specification of a flexible key for any given Node/Link
such that global uniqueness of the NLRI is ensured. information such that global uniqueness of the NLRI is ensured.
3.2.1.2. Local Node Descriptors 3.2.1.2. Local Node Descriptors
The Local Node Descriptors TLV contains Node Descriptors for the node The Local Node Descriptors TLV contains Node Descriptors for the node
anchoring the local end of the link. This is a mandatory TLV in all anchoring the local end of the link. This is a mandatory TLV in all
three types of NLRIs. The length of this TLV is variable. The value three types of NLRIs. The length of this TLV is variable. The value
contains one or more Node Descriptor Sub-TLVs defined in Section contains one or more Node Descriptor Sub-TLVs defined in
3.2.1.4. Section 3.2.1.4.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
// Node Descriptor Sub-TLVs (variable) // // Node Descriptor Sub-TLVs (variable) //
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 10: Local Node Descriptors TLV format
3.2.1.3. Remote Node Descriptors 3.2.1.3. Remote Node Descriptors
The Remote Node Descriptors contains Node Descriptors for the node The Remote Node Descriptors contains Node Descriptors for the node
anchoring the remote end of the link. This is a mandatory TLV for anchoring the remote end of the link. This is a mandatory TLV for
link NLRIs. The length of this TLV is variable. The value contains link NLRIs. The length of this TLV is variable. The value contains
one or more Node Descriptor Sub-TLVs defined in Section 3.2.1.4. one or more Node Descriptor Sub-TLVs defined in Section 3.2.1.4.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | | |
// Node Descriptor Sub-TLVs (variable) // // Node Descriptor Sub-TLVs (variable) //
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 11: Remote Node Descriptors TLV format
3.2.1.4. Node Descriptor Sub-TLVs 3.2.1.4. 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:
+--------------------+-------------------+----------+ +--------------------+-------------------+----------+
| Sub-TLV Code Point | Description | Length | | Sub-TLV Code Point | Description | Length |
+--------------------+-------------------+----------+ +--------------------+-------------------+----------+
| 512 | Autonomous System | 4 | | 512 | Autonomous System | 4 |
| 513 | BGP-LS Identifier | 4 | | 513 | BGP-LS Identifier | 4 |
| 514 | Area-ID | 4 | | 514 | OSPF Area-ID | 4 |
| 515 | IGP Router-ID | Variable | | 515 | IGP Router-ID | Variable |
+--------------------+-------------------+----------+ +--------------------+-------------------+----------+
Table 4: Node Descriptor Sub-TLVs
The sub-TLV values in Node Descriptor TLVs are defined as follows: The sub-TLV values in Node Descriptor TLVs are defined as follows:
Autonomous System: opaque value (32 Bit AS Number) Autonomous System: opaque value (32 Bit AS Number)
BGP-LS Identifier: opaque value (32 Bit ID). In conjunction with ASN, BGP-LS Identifier: opaque value (32 Bit ID). In conjunction with
uniquely identifies the BGP-LS domain. The combination of ASN and ASN, uniquely identifies the BGP-LS domain. The combination of
BGP-LS ID MUST be globally unique. All BGP-LS speakers within an ASN and BGP-LS ID MUST be globally unique. All BGP-LS speakers
IGP flooding-set (set of IGP nodes within which an LSP/LSA is within an IGP flooding-set (set of IGP nodes within which an LSP/
flooded) MUST use the same ASN, BGP-LS ID tuple. If an IGP domain LSA is flooded) MUST use the same ASN, BGP-LS ID tuple. If an IGP
consists of multiple flooding-sets, then all BGP-LS speakers domain consists of multiple flooding-sets, then all BGP-LS
within the IGP domain SHOULD use the same ASN, BGP-LS ID tuple. speakers within the IGP domain SHOULD use the same ASN, BGP-LS ID
The ASN, BGP Router-ID tuple (which is globally unique [RFC6286] ) tuple. The ASN, BGP Router-ID tuple (which is globally unique
of one of the BGP-LS speakers within the flooding-set (or IGP [RFC6286] ) of one of the BGP-LS speakers within the flooding-set
domain) may be used for all BGP-LS speakers in that flooding-set (or IGP domain) may be used for all BGP-LS speakers in that
(or IGP domain). flooding-set (or IGP domain).
Area ID: It is used to identify the 32 Bit area to which the NLRI Area ID: It is used to identify the 32 Bit area to which the NLRI
belongs. Area Identifier allows the different NLRIs of the same belongs. Area Identifier allows the different NLRIs of the same
router to be discriminated. router to be discriminated.
IGP Router ID: opaque value. This is a mandatory TLV. For an IS-IS IGP Router ID: opaque value. This is a mandatory TLV. For an IS-IS
non-Pseudonode, this contains 6 octet ISO node-ID (ISO system-ID). non-Pseudonode, this contains 6 octet ISO node-ID (ISO system-ID).
For an IS-IS Pseudonode corresponding to a LAN, this contains 6 For an IS-IS Pseudonode corresponding to a LAN, this contains 6
octet ISO node-ID of the "Designated Intermediate System" (DIS) octet ISO node-ID of the "Designated Intermediate System" (DIS)
followed by one octet nonzero PSN identifier (7 octet in total). followed by one octet nonzero PSN identifier (7 octets in total).
For an OSPFv2 or OSPFv3 non-"Pseudonode", this contains 4 octet For an OSPFv2 or OSPFv3 non-"Pseudonode", this contains the 4
Router-ID. For an OSPFv2 "Pseudonode" representing a LAN, this octet Router-ID. For an OSPFv2 "Pseudonode" representing a LAN,
contains 4 octet Router-ID of the designated router (DR) followed this contains the 4 octet Router-ID of the designated router (DR)
by 4 octet IPv4 address of the DR's interface to the LAN (8 octet followed by the 4 octet IPv4 address of the DR's interface to the
in total). Similarly, for an OSPFv3 "Pseudonode", this contains 4 LAN (8 octets in total). Similarly, for an OSPFv3 "Pseudonode",
octet Router-ID of the DR followed by 4 octet interface identifier this contains the 4 octet Router-ID of the DR followed by the 4
of the DR's interface to the LAN (8 octet in total). The TLV size octet interface identifier of the DR's interface to the LAN (8
in combination with protocol identifier enables the decoder to octets in total). The TLV size in combination with protocol
determine the type of the node. identifier enables the decoder to determine the type of the node.
There can be at most one instance of each sub-TLV type present in There can be at most one instance of each sub-TLV type present in
any Node Descriptor. The TLV ordering within a Node descriptor any Node Descriptor. The sub-TLVs within a Node descriptor MUST
MUST be kept in order of increasing numeric value of type. This be arranged in ascending order by sub-TLV type. This needs to be
needs to be done in order to compare NLRIs, even when an done in order to compare NLRIs, even when an implementation
implementation encounters an unknown sub-TLV. Using stable sorting encounters an unknown sub-TLV. Using stable sorting an
an implementation can do binary comparison of NLRIs and hence implementation can do binary comparison of NLRIs and hence allow
allow incremental deployment of new key sub-TLVs. incremental deployment of new key sub-TLVs.
3.2.1.5. Multi-Topology ID 3.2.1.5. Multi-Topology ID
The Multi-Topology ID (MT-ID) TLV carries one or more IS-IS or OSPF The Multi-Topology ID (MT-ID) TLV carries one or more IS-IS or OSPF
Multi-Topology IDs for a link, node or prefix. Multi-Topology IDs for a link, node or prefix.
Semantics of the IS-IS MT-ID are defined in RFC5120, Section 7.2 Semantics of the IS-IS MT-ID are defined in RFC5120, Section 7.2
[RFC5120]. Semantics of the OSPF MT-ID are defined in RFC4915, [RFC5120]. Semantics of the OSPF MT-ID are defined in RFC4915,
Section 3.7 [RFC4915]. If the value in the MT-ID TLV is derived from Section 3.7 [RFC4915]. If the value in the MT-ID TLV is derived from
OSPF, then the upper 9 bits MUST be set to 0. Bits R are reserved, OSPF, then the upper 9 bits MUST be set to 0. Bits R are reserved,
SHOULD be set to 0 when originated and ignored on receipt. SHOULD be set to 0 when originated and ignored on receipt.
The format of the MT-ID TLV is shown in the following figure. The format of the MT-ID TLV 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length=2*n | | Type | Length=2*n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|R R R R| Multi-Topology ID 1 | .... // |R R R R| Multi-Topology ID 1 | .... //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// .... |R R R R| Multi-Topology ID n | // .... |R R R R| Multi-Topology ID n |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 12: Multi-Topology ID TLV format
where Type is 263, Length is 2*n and n is the number of MT-IDs where Type is 263, Length is 2*n and n is the number of MT-IDs
carried in the TLV. carried in the TLV.
The MT-ID TLV MAY be present in a Link Descriptor, a Prefix The MT-ID TLV MAY be present in a Link Descriptor, a Prefix
Descriptor, or in the BGP-LS attribute of a node NLRI. In Link or Descriptor, or in the BGP-LS attribute of a node NLRI. In a Link or
Prefix Descriptor, only one MT-ID TLV containing only the MT-ID of Prefix Descriptor, only a single MT-ID TLV containing the MT-ID of
the topology where the link or the prefix belongs is allowed. In the the topology where the link or the prefix is reachable is allowed.
BGP-LS attribute of a node NLRI, one MT-ID TLV containing the array In case one wants to advertise multiple topologies for a given Link
of MT-IDs of all topologies where the node belongs can be present. Descriptor or Prefix Descriptor, multiple NRLIs need to be generated
where each NLRI contains an unique MT-ID. In the BGP-LS attribute of
a node NLRI, one MT-ID TLV containing the array of MT-IDs of all
topologies where the node is reachable is allowed.
3.2.2. Link Descriptors 3.2.2. 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 among multiple parallel descriptor' TLVs uniquely identify a link among multiple parallel
links between a pair of anchor routers. A link described by the Link links between a pair of anchor routers. A link described by the Link
descriptor TLVs actually is a "half-link", a unidirectional descriptor TLVs actually is a "half-link", a unidirectional
representation of a logical link. In order to fully describe a representation of a logical link. In order to fully describe a
single logical link two originating routers advertise a half-link single logical link, two originating routers advertise a half-link
each, i.e. two link NLRIs are advertised for a given point-to-point each, i.e., two link NLRIs are advertised for a given point-to-point
link. link.
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 TLVs are valid as Link Descriptors in the Link NLRI: The following TLVs are valid as Link Descriptors in the Link NLRI:
+------------+--------------------+---------------+-----------------+ +-----------+---------------------+---------------+-----------------+
| TLV Code | Description | IS-IS TLV | Value defined | | TLV Code | Description | IS-IS TLV | Value defined |
| Point | | /Sub-TLV | in: | | Point | | /Sub-TLV | in: |
+------------+--------------------+---------------+-----------------+ +-----------+---------------------+---------------+-----------------+
| 258 | Link Local/Remote | 22/4 | [RFC5307]/1.1 | | 258 | Link Local/Remote | 22/4 | [RFC5307]/1.1 |
| | Identifiers | | | | | Identifiers | | |
| 259 | IPv4 interface | 22/6 | [RFC5305]/3.2 | | 259 | IPv4 interface | 22/6 | [RFC5305]/3.2 |
| | address | | | | | address | | |
| 260 | IPv4 neighbor | 22/8 | [RFC5305]/3.3 | | 260 | IPv4 neighbor | 22/8 | [RFC5305]/3.3 |
| | address | | | | | address | | |
| 261 | IPv6 interface | 22/12 | [RFC6119]/4.2 | | 261 | IPv6 interface | 22/12 | [RFC6119]/4.2 |
| | address | | | | | address | | |
| 262 | IPv6 neighbor | 22/13 | [RFC6119]/4.3 | | 262 | IPv6 neighbor | 22/13 | [RFC6119]/4.3 |
| | address | | | | | address | | |
| 263 | Multi-Topology | --- | Section 3.2.1.5 | | 263 | Multi-Topology | --- | Section 3.2.1.5 |
| | Identifier | | | | | Identifier | | |
+------------+--------------------+---------------+-----------------+ +-----------+---------------------+---------------+-----------------+
Table 5: Link Descriptor TLVs
The information about a link present in the LSA/LSP originated by the The information about a link present in the LSA/LSP originated by the
local node of the link determines the set of TLVs in the Link local node of the link determines the set of TLVs in the Link
Descriptor of the link. Descriptor of the link.
If interface and neighbor addresses, either IPv4 or IPv6, are If interface and neighbor addresses, either IPv4 or IPv6, are
present, then the IP address TLVs are included in the link present, then the IP address TLVs are included in the link
descriptor, but not the link local/remote Identifier TLV. The link descriptor, but not the link local/remote Identifier TLV. The
local/remote identifiers MAY be included in the link attribute. link local/remote identifiers MAY be included in the link
attribute.
If interface and neighbor addresses are not present and the link If interface and neighbor addresses are not present and the link
local/remote identifiers are present, then the link local/remote local/remote identifiers are present, then the link local/remote
Identifier TLV is included in link descriptor. Identifier TLV is included in the link descriptor.
The Multi-Topology Identifier TLV is included in link descriptor The Multi-Topology Identifier TLV is included in link descriptor
if that information is present. if that information is present.
3.2.3. Prefix Descriptors 3.2.3. Prefix Descriptors
The 'Prefix Descriptor' field is a set of Type/Length/Value (TLV) The 'Prefix Descriptor' field is a set of Type/Length/Value (TLV)
triplets. 'Prefix Descriptor' TLVs uniquely identify an IPv4 or IPv6 triplets. 'Prefix Descriptor' TLVs uniquely identify an IPv4 or IPv6
Prefix originated by a Node. The following TLVs are valid as Prefix Prefix originated by a Node. The following TLVs are valid as Prefix
Descriptors in the IPv4/IPv6 Prefix NLRI: Descriptors in the IPv4/IPv6 Prefix NLRI:
+-----------+--------------------------+------------+---------------+ +--------------+-----------------------+----------+-----------------+
| TLV Code | Description | Length | Value defined | | TLV Code | Description | Length | Value defined |
| Point | | | in: | | Point | | | in: |
+-----------+--------------------------+------------+---------------+ +--------------+-----------------------+----------+-----------------+
| 263 | Multi-Topology | variable | Section | | 263 | Multi-Topology | variable | Section 3.2.1.5 |
| | Identifier | | 3.2.1.5 | | | Identifier | | |
| 264 | OSPF Route Type | 1 | Section | | 264 | OSPF Route Type | 1 | Section 3.2.3.1 |
| | | | 3.2.3.1 | | 265 | IP Reachability | variable | Section 3.2.3.2 |
| 265 | IP Reachability | variable | Section | | | Information | | |
| | Information | | 3.2.3.2 | +--------------+-----------------------+----------+-----------------+
+-----------+--------------------------+------------+---------------+
Table 6: Prefix Descriptor TLVs
3.2.3.1. OSPF Route Type 3.2.3.1. OSPF Route Type
OSPF Route Type is an optional TLV that MAY be present in Prefix OSPF Route Type is an optional TLV that MAY be present in Prefix
NLRIs. It is used to identify the OSPF route-type of the prefix. It 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 is used when an OSPF prefix is advertised in the OSPF domain with
multiple different route-types. The Route Type TLV allows to multiple route-types. The Route Type TLV allows to discrimination of
discriminate these advertisements. The format of the OSPF Route Type these advertisements. The format of the OSPF Route Type TLV is shown
TLV is shown in the following figure. 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Route Type | | Route Type |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
where the Type and Length fields of the TLV are defined in Table 4. Figure 13: OSPF Route Type TLV Format
where the Type and Length fields of the TLV are defined in Table 6.
The OSPF Route Type field values are defined in the OSPF protocol, The OSPF Route Type field values are defined in the OSPF protocol,
and can be one of the following: and can be one of the following:
Intra-Area (0x1) Intra-Area (0x1)
Inter-Area (0x2) Inter-Area (0x2)
External 1 (0x3) External 1 (0x3)
External 2 (0x4) External 2 (0x4)
NSSA 1 (0x5) NSSA 1 (0x5)
NSSA 2 (0x6) NSSA 2 (0x6)
3.2.3.2. IP Reachability Information 3.2.3.2. IP Reachability Information
skipping to change at page 17, line 16 skipping to change at page 18, line 25
External 2 (0x4) External 2 (0x4)
NSSA 1 (0x5) NSSA 1 (0x5)
NSSA 2 (0x6) NSSA 2 (0x6)
3.2.3.2. IP Reachability Information 3.2.3.2. IP Reachability Information
The IP Reachability Information is a mandatory TLV that contains one The IP Reachability Information is a mandatory TLV that contains one
IP address prefix (IPv4 or IPv6) originally advertised in the IGP IP address prefix (IPv4 or IPv6) originally advertised in the IGP
topology. Its purpose is to glue a particular BGP service NLRI vi topology. Its purpose is to glue a particular BGP service NLRI by
virtue of its BGP next-hop to a given Node in the LSDB. A router virtue of its BGP next-hop to a given Node in the LSDB. A router
SHOULD advertise an IP Prefix NLRI for each of its BGP Next-hops. SHOULD advertise an IP Prefix NLRI for each of its BGP Next-hops.
The format of the IP Reachability Information TLV is shown in the The format of the IP Reachability Information TLV is shown in the
following figure: 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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | | Type | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Prefix Length | IP Prefix (variable) // | Prefix Length | IP Prefix (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The Type and Length fields of the TLV are defined in Table 4. The Figure 14: IP Reachability Information TLV Format
The Type and Length fields of the TLV are defined in Table 6. The
following two fields determine the address-family reachability following two fields determine the address-family reachability
information. The 'Prefix Length' field contains the length of the information. The 'Prefix Length' field contains the length of the
prefix in bits. The 'IP Prefix' field contains the most significant prefix in bits. The 'IP Prefix' field contains the most significant
octets of the prefix; i.e., 1 octet for prefix length 1 up to 8, 2 octets of the prefix; 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 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. 24 and 4 octets for prefix length 25 up to 32, etc.
3.3. The BGP-LS Attribute 3.3. The BGP-LS Attribute
This is an optional, non-transitive BGP attribute that is used to This is an optional, non-transitive BGP attribute that is used to
skipping to change at page 18, line 5 skipping to change at page 19, line 20
following section. This attribute SHOULD only be included with Link- following section. This attribute SHOULD only be included with Link-
State NLRIs. This attribute MUST be ignored for all other address- State NLRIs. This attribute MUST be ignored for all other address-
families. families.
3.3.1. Node Attribute TLVs 3.3.1. Node Attribute TLVs
Node attribute TLVs are the TLVs that may be encoded in the BGP-LS Node attribute TLVs are the TLVs that may be encoded in the BGP-LS
attribute with a node NLRI. The following node attribute TLVs are attribute with a node NLRI. The following node attribute TLVs are
defined: defined:
+-----------+----------------------+------------+-------------------+ +--------------+-----------------------+----------+-----------------+
| TLV Code | Description | Length | Value defined in: | | TLV Code | Description | Length | Value defined |
| Point | | | | | Point | | | in: |
+-----------+----------------------+------------+-------------------+ +--------------+-----------------------+----------+-----------------+
| 263 | Multi-Topology | variable | Section 3.2.1.5 | | 263 | Multi-Topology | variable | Section 3.2.1.5 |
| | Identifier | | | | | Identifier | | |
| 1024 | Node Flag Bits | 1 | Section 3.3.1.1 | | 1024 | Node Flag Bits | 1 | Section 3.3.1.1 |
| 1025 | Opaque Node | variable | Section 3.3.1.5 | | 1025 | Opaque Node | variable | Section 3.3.1.5 |
| | Properties | | | | | Properties | | |
| 1026 | Node Name | variable | Section 3.3.1.3 | | 1026 | Node Name | variable | Section 3.3.1.3 |
| 1027 | IS-IS Area | variable | Section 3.3.1.2 | | 1027 | IS-IS Area Identifier | variable | Section 3.3.1.2 |
| | Identifier | | | | 1028 | IPv4 Router-ID of | 4 | [RFC5305]/4.3 |
| 1028 | IPv4 Router-ID of | 4 | [RFC5305]/4.3 | | | Local Node | | |
| | Local Node | | | | 1029 | IPv6 Router-ID of | 16 | [RFC6119]/4.1 |
| 1029 | IPv6 Router-ID of | 16 | [RFC6119]/4.1 | | | Local Node | | |
| | Local Node | | | +--------------+-----------------------+----------+-----------------+
+-----------+----------------------+------------+-------------------+
Table 7: Node Attribute TLVs
3.3.1.1. Node Flag Bits TLV 3.3.1.1. Node Flag Bits TLV
The Node Flag Bits TLV carries a bit mask describing node attributes. The Node Flag Bits TLV carries a bit mask describing node attributes.
The value is a variable length bit array of flags, where each bit The value is a variable length bit array of flags, where each bit
represents a node capability. 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|O|T|E|A| Reserved| |O|T|E|B| Reserved|
+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+
Figure 15: Node Flag Bits TLV format
The bits are defined as follows: The bits are defined as follows:
+----------+-------------------------+-----------+ +----------+-------------------------+-----------+
| Bit | Description | Reference | | Bit | Description | Reference |
+----------+-------------------------+-----------+ +----------+-------------------------+-----------+
| 'O' | Overload Bit | [RFC1195] | | 'O' | Overload Bit | [RFC1195] |
| 'T' | Attached Bit | [RFC1195] | | 'T' | Attached Bit | [RFC1195] |
| 'E' | External Bit | [RFC2328] | | 'E' | External Bit | [RFC2328] |
| 'A' | ABR Bit | [RFC2328] | | 'B' | ABR Bit | [RFC2328] |
| Reserved | Reserved for future use | | | Reserved | Reserved for future use | |
+----------+-------------------------+-----------+ +----------+-------------------------+-----------+
Table 8: Node Flag Bits Definitions
3.3.1.2. IS-IS Area Identifier TLV 3.3.1.2. IS-IS Area Identifier TLV
An IS-IS node can be part of one or more IS-IS areas. Each of these An IS-IS node can be part of one or more IS-IS areas. Each of these
area addresses is carried in the IS-IS Area Identifier TLV. If more area addresses is carried in the IS-IS Area Identifier TLV. If
than one Area Addresses are present, multiple TLVs are used to encode multiple Area Addresses are present, multiple TLVs are used to encode
them. The IS-IS Area Identifier TLV may be present in the BGP-LS them. The IS-IS Area Identifier TLV may be present in the BGP-LS
attribute only with the Link-State Node NLRI. attribute only when advertised in the Link-State Node 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Area Identifier (variable) // // Area Identifier (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 16: IS-IS Area Identifier TLV Format
3.3.1.3. Node Name TLV 3.3.1.3. Node Name TLV
The Node Name TLV is optional. Its structure and encoding has been The Node Name TLV is optional. Its structure and encoding has been
borrowed from [RFC5301]. The value field identifies the symbolic borrowed from [RFC5301]. The value field identifies the symbolic
name of the router node. This symbolic name can be the FQDN for the name of the router node. This symbolic name can be the FQDN for the
router, it can be a subset of the FQDN, or it can be any string router, it can be a subset of the FQDN, or it can be any string
operators want to use for the router. The use of FQDN or a subset of operators want to use for the router. The use of FQDN or a subset of
it is strongly recommended. it is strongly RECOMMENDED.
The Value field is encoded in 7-bit ASCII. If a user-interface for The Value field is encoded in 7-bit ASCII. If a user-interface for
configuring or displaying this field permits Unicode characters, that configuring or displaying this field permits Unicode characters, that
user-interface is responsible for applying the ToASCII and/or user-interface is responsible for applying the ToASCII and/or
ToUnicode algorithm as described in [RFC5890] to achieve the correct ToUnicode algorithm as described in [RFC5890] to achieve the correct
format for transmission or display. format for transmission or display.
Altough [RFC5301] is a IS-IS specific extension, usage of the Node Altough [RFC5301] is an IS-IS specific extension, usage of the Node
Name TLV is possible for all protocols. How a router derives and Name TLV is possible for all protocols. How a router derives and
injects node names for e.g. OSPF nodes, is outside of the scope of injects node names for e.g. OSPF nodes, is outside of the scope of
this document. this document.
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 Name (variable) // // Node Name (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 17: Node Name format
3.3.1.4. Local IPv4/IPv6 Router-ID 3.3.1.4. Local IPv4/IPv6 Router-ID
The local IPv4/IPv6 Router-ID TLVs are used to describe auxiliary The local IPv4/IPv6 Router-ID TLVs are used to describe auxiliary
Router-IDs that the IGP might be using, e.g., for TE and migration Router-IDs that the IGP might be using, e.g., for TE and migration
purposes like correlating a Node-ID between different protocols. If purposes like correlating a Node-ID between different protocols. If
there is more than one auxiliary Router-ID of a given type, then each there is more than one auxiliary Router-ID of a given type, then each
one is encoded in its own TLV. one is encoded in its own TLV.
3.3.1.5. Opaque Node Attribute TLV 3.3.1.5. Opaque Node Attribute TLV
The Opaque Node attribute TLV is an envelope that transparently
The Opaque Node Attribute TLV is an envelope that transparently
carries optional node attribute TLVs advertised by a router. An carries optional node attribute TLVs advertised by a router. An
originating router shall use this TLV for encoding information originating router shall use this TLV for encoding information
specific to the protocol advertised in the NLRI header Protocol-ID specific to the protocol advertised in the NLRI header Protocol-ID
field or new protocol extensions to the protocol as advertised in the field or new protocol extensions to the protocol as advertised in the
NLRI header Protocol-ID field for which there is no protocol neutral NLRI header Protocol-ID field for which there is no protocol neutral
representation in the BGP link-state NLRI. A router for example representation in the BGP link-state NLRI. The primary use of the
Opaque Node Attribute TLV is to bridge the document lag between e.g.
a new IGP Link-state attribute being defined and the 'protocol-
neutral' BGP-LS extensions being published. A router for example
could use this extension in order to advertise the native protocols could use this extension in order to advertise the native protocols
node attribute TLVs, such as the OSPF Router Informational node attribute TLVs, such as the OSPF Router Informational
Capabilities TLV defined in [RFC4970], or the IGP TE Node Capability Capabilities TLV defined in [RFC4970], or the IGP TE Node Capability
Descriptor TLV described in [RFC5073]. Descriptor TLV described in [RFC5073].
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Opaque node attributes (variable) // // Opaque node attributes (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 18: Opaque Node attribute format
3.3.2. Link Attribute TLVs 3.3.2. Link Attribute TLVs
Link attribute TLVs are TLVs that may be encoded in the BGP-LS Link attribute TLVs are TLVs that may be encoded in the BGP-LS
attribute with a link NLRI. Each 'Link Attribute' is a Type/Length/ attribute with a link NLRI. Each 'Link Attribute' is a Type/Length/
Value (TLV) triplet formatted as defined in Section 3.1. The format Value (TLV) triplet formatted as defined in Section 3.1. The format
and semantics of the 'value' fields in some 'Link Attribute' TLVs and semantics of the 'value' fields in some 'Link Attribute' TLVs
correspond to the format and semantics of value fields in IS-IS correspond to the format and semantics of value fields in IS-IS
Extended IS Reachability sub-TLVs, defined in [RFC5305] and Extended IS Reachability sub-TLVs, defined in [RFC5305] and
[RFC5307]. Other 'Link Attribute' TLVs are defined in this document. [RFC5307]. Other 'Link Attribute' TLVs are defined in this document.
Although the encodings for 'Link Attribute' TLVs were originally Although the encodings for 'Link Attribute' TLVs were originally
defined for IS-IS, the TLVs can carry data sourced either by IS-IS or defined for IS-IS, the TLVs can carry data sourced either by IS-IS or
OSPF. 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:
+----------+----------------------+---------------+-----------------+ +-----------+---------------------+--------------+------------------+
| TLV Code | Description | IS-IS TLV | Defined in: | | TLV Code | Description | IS-IS TLV | Defined in: |
| Point | | /Sub-TLV | | | Point | | /Sub-TLV | |
+----------+----------------------+---------------+-----------------+ +-----------+---------------------+--------------+------------------+
| 1028 | IPv4 Router-ID of | 134/--- | [RFC5305]/4.3 | | 1028 | IPv4 Router-ID of | 134/--- | [RFC5305]/4.3 |
| | Local Node | | | | | Local Node | | |
| 1029 | IPv6 Router-ID of | 140/--- | [RFC6119]/4.1 | | 1029 | IPv6 Router-ID of | 140/--- | [RFC6119]/4.1 |
| | Local Node | | | | | Local Node | | |
| 1030 | IPv4 Router-ID of | 134/--- | [RFC5305]/4.3 | | 1030 | IPv4 Router-ID of | 134/--- | [RFC5305]/4.3 |
| | Remote Node | | | | | Remote Node | | |
| 1031 | IPv6 Router-ID of | 140/--- | [RFC6119]/4.1 | | 1031 | IPv6 Router-ID of | 140/--- | [RFC6119]/4.1 |
| | Remote Node | | | | | Remote Node | | |
| 1032 | Link Local/Remote | 22/4 | [RFC5307]/1.1 | | 1032 | Link Local/Remote | 22/4 | [RFC5307]/1.1 |
| | Identifiers | | | | | Identifiers | | |
| 1088 | Administrative group | 22/3 | [RFC5305]/3.1 | | 1088 | Administrative | 22/3 | [RFC5305]/3.1 |
| | (color) | | | | | group (color) | | |
| 1089 | Maximum link | 22/9 | [RFC5305]/3.3 | | 1089 | Maximum link | 22/9 | [RFC5305]/3.3 |
| | bandwidth | | | | | bandwidth | | |
| 1090 | Max. reservable link | 22/10 | [RFC5305]/3.5 | | 1090 | Max. reservable | 22/10 | [RFC5305]/3.5 |
| | bandwidth | | | | | link bandwidth | | |
| 1091 | Unreserved bandwidth | 22/11 | [RFC5305]/3.6 | | 1091 | Unreserved | 22/11 | [RFC5305]/3.6 |
| 1092 | TE Default Metric | 22/18 | Section | | | bandwidth | | |
| | | | 3.3.2.3/ | | 1092 | TE Default Metric | 22/18 | Section 3.3.2.3/ |
| 1093 | Link Protection Type | 22/20 | [RFC5307]/1.2 | | 1093 | Link Protection | 22/20 | [RFC5307]/1.2 |
| 1094 | MPLS Protocol Mask | --- | Section 3.3.2.2 | | | Type | | |
| 1095 | IGP Metric | --- | Section 3.3.2.4 | | 1094 | MPLS Protocol Mask | --- | Section 3.3.2.2 |
| 1096 | Shared Risk Link | --- | Section 3.3.2.5 | | 1095 | IGP Metric | --- | Section 3.3.2.4 |
| | Group | | | | 1096 | Shared Risk Link | --- | Section 3.3.2.5 |
| 1097 | Opaque link | --- | Section 3.3.2.6 | | | Group | | |
| | attribute | | | | 1097 | Opaque link | --- | Section 3.3.2.6 |
| 1098 | Link Name attribute | --- | Section 3.3.2.7 | | | attribute | | |
+----------+----------------------+---------------+-----------------+ | 1098 | Link Name attribute | --- | Section 3.3.2.7 |
+-----------+---------------------+--------------+------------------+
Table 9: Link Attribute TLVs
3.3.2.1. IPv4/IPv6 Router-ID 3.3.2.1. IPv4/IPv6 Router-ID
The local/remote IPv4/IPv6 Router-ID TLVs are used to describe The local/remote IPv4/IPv6 Router-ID TLVs are used to describe
auxiliary Router-IDs that the IGP might be using, e.g., for TE auxiliary Router-IDs that the IGP might be using, e.g., for TE
purposes. All auxiliary Router-IDs of both the local and the remote purposes. All auxiliary Router-IDs of both the local and the remote
node MUST be included in the link attribute of each link NLRI. If node MUST be included in the link attribute of each link NLRI. If
there are more than one auxiliary Router-ID of a given type, then there are more than one auxiliary Router-ID of a given type, then
multiple TLVs are used to encode them. multiple TLVs are used to encode them.
3.3.2.2. MPLS Protocol Mask TLV 3.3.2.2. MPLS Protocol Mask TLV
The MPLS Protocol TLV carries a bit mask describing which MPLS The MPLS Protocol TLV carries a bit mask describing which MPLS
signaling protocols are enabled. The length of this TLV is 1. The 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 MPLS value is a bit array of 8 flags, where each bit represents an MPLS
Protocol capability. Protocol capability.
0 1 2 3 Generation of the MPLS Protocol Mask TLV is only valid for
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 originators which have local link insight, like for example Protocol-
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ IDs 'Static' or 'Direct' as per Table 2. The MPLS Protocol Mask TLV
| Type | Length | MUST NOT be included in NLRIs with protocol-IDs 'IS-IS L1', 'IS-IS
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ L2', 'OSPFv2' or 'OSPFv3' as per Table 2.
|L|R| Reserved |
+-+-+-+-+-+-+-+-+ 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|L|R| Reserved |
+-+-+-+-+-+-+-+-+
Figure 19: MPLS Protocol TLV
The following bits are defined: The following bits are defined:
+----------------+----------------------------------+---------------+ +------------+------------------------------------------+-----------+
| Bit | Description | Reference | | Bit | Description | Reference |
+----------------+----------------------------------+---------------+ +------------+------------------------------------------+-----------+
| 'L' | Label Distribution Protocol | [RFC5036] | | 'L' | Label Distribution Protocol (LDP) | [RFC5036] |
| | (LDP) | | | 'R' | Extension to RSVP for LSP Tunnels (RSVP- | [RFC3209] |
| 'R' | Extension to RSVP for LSP | [RFC3209] | | | TE) | |
| | Tunnels (RSVP-TE) | | | 'Reserved' | Reserved for future use | |
| 'Reserved' | Reserved for future use | | +------------+------------------------------------------+-----------+
+----------------+----------------------------------+---------------+
Table 10: MPLS Protocol Mask TLV Codes
3.3.2.3. TE Default Metric TLV 3.3.2.3. TE Default Metric TLV
The TE Default Metric TLV carries the TE-metric for this link. The The TE Default Metric TLV carries the TE-metric for this link. The
length of this TLV is fixed at 4 octets. If a source protocol (e.g. length of this TLV is fixed at 4 octets. If a source protocol (e.g.
IS-IS) does not support a Metric width of 32 bits then the high order IS-IS) does not support a Metric width of 32 bits then the high order
octet MUST be set to zero. octet MUST be set to zero.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TE Default Link Metric | | TE Default Link Metric |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 20: TE Default Metric TLV format
3.3.2.4. IGP Metric TLV 3.3.2.4. IGP Metric TLV
The IGP Metric TLV carries the metric for this link. The length of The IGP Metric TLV carries the metric for this link. The length of
this TLV is variable, depending on the metric width of the underlying this TLV is variable, depending on the metric width of the underlying
protocol. IS-IS small metrics have a length of 1 octet (the two most protocol. IS-IS small metrics have a length of 1 octet (the two most
significant bits are ignored). OSPF metrics have a length of two significant bits are ignored). OSPF link metrics have a length of
octects. IS-IS wide-metrics have a length of three octets. two octects. IS-IS wide-metrics have a length of three octets.
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 (variable length) // // IGP Link Metric (variable length) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 21: Metric TLV format
3.3.2.5. Shared Risk Link Group TLV 3.3.2.5. Shared Risk Link Group TLV
The Shared Risk Link Group (SRLG) TLV carries the Shared Risk Link The Shared Risk Link Group (SRLG) TLV carries the Shared Risk Link
Group information (see Section 2.3, "Shared Risk Link Group 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 22. The length of this TLV is 4 * has 4 octets, as shown in Figure 22. 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Note that there is no SRLG TLV in OSPF-TE. In IS-IS the SRLG Figure 22: Shared Risk Link Group TLV format
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]. In Link-State NLRI both IPv4 and IPv6 SRLG defined in [RFC6119]. In Link-State NLRI both IPv4 and IPv6 SRLG
information are carried in a single TLV. information are carried in a single TLV.
3.3.2.6. Opaque Link Attribute TLV 3.3.2.6. Opaque Link Attribute TLV
The Opaque link attribute TLV is an envelope that transparently The Opaque link Attribute TLV is an envelope that transparently
carries optional link atrribute TLVs advertised by a router. An carries optional link atrribute TLVs advertised by a router. An
originating router shall use this TLV for encoding information originating router shall use this TLV for encoding information
specific to the protocol advertised in the NLRI header Protocol-ID specific to the protocol advertised in the NLRI header Protocol-ID
field or new protocol extensions to the protocol as advertised in the field or new protocol extensions to the protocol as advertised in the
NLRI header Protocol-ID field for which there is no protocol neutral NLRI header Protocol-ID field for which there is no protocol neutral
representation in the BGP link-state NLRI. representation in the BGP link-state NLRI. The primary use of the
Opaque Link Attribute TLV is to bridge the document lag between e.g.
a new IGP Link-state attribute being defined and the 'protocol-
neutral' BGP-LS extensions being published.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Opaque link attributes (variable) // // Opaque link attributes (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 23: Opaque link attribute format
3.3.2.7. Link Name TLV 3.3.2.7. Link Name TLV
The Link Name TLV is optional. The value field identifies the The Link Name TLV is optional. The value field identifies the
symbolic name of the router link. This symbolic name can be the FQDN symbolic name of the router link. This symbolic name can be the FQDN
for the link, it can be a subset of the FQDN, or it can be any string for the link, it can be a subset of the FQDN, or it can be any string
operators want to use for the link. The use of FQDN or a subset of operators want to use for the link. The use of FQDN or a subset of
it is strongly recommended. it is strongly RECOMMENDED.
The Value field is encoded in 7-bit ASCII. If a user-interface for The Value field is encoded in 7-bit ASCII. If a user-interface for
configuring or displaying this field permits Unicode characters, that configuring or displaying this field permits Unicode characters, that
user-interface is responsible for applying the ToASCII and/or user-interface is responsible for applying the ToASCII and/or
ToUnicode algorithm as described in [RFC5890] to achieve the correct ToUnicode algorithm as described in [RFC5890] to achieve the correct
format for transmission or display. format for transmission or display.
How a router derives and injects link names is outside of the scope How a router derives and injects link names is outside of the scope
of this document. of this document.
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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Link Name (variable) // // Link Name (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 24: Link Name format
3.3.3. Prefix Attribute TLVs 3.3.3. Prefix Attribute TLVs
Prefixes are learned from the IGP topology (IS-IS or OSPF) with a set Prefixes are learned from the IGP topology (IS-IS or OSPF) with a set
of IGP attributes (such as metric, route tags, etc.) that MUST be of IGP attributes (such as metric, route tags, etc.) that MUST be
reflected into the LINK_STATE attribute. This section describes the reflected into the LINK_STATE attribute. This section describes the
different attributes related to the IPv4/IPv6 prefixes. Prefix different attributes related to the IPv4/IPv6 prefixes. Prefix
Attributes TLVs SHOULD be used when advertising NLRI types 3 and 4 Attributes TLVs SHOULD be used when advertising NLRI types 3 and 4
only. The following attributes TLVs are defined: only. The following attributes TLVs are defined:
+-------------+---------------------+--------------+----------------+ +---------------+----------------------+----------+-----------------+
| TLV Code | Description | Length | Reference | | TLV Code | Description | Length | Reference |
| Point | | | | | Point | | | |
+-------------+---------------------+--------------+----------------+ +---------------+----------------------+----------+-----------------+
| 1152 | IGP Flags | 1 | Section | | 1152 | IGP Flags | 1 | Section 3.3.3.1 |
| | | | 3.3.3.1 | | 1153 | Route Tag | 4*n | Section 3.3.3.2 |
| 1153 | Route Tag | 4*n | Section | | 1154 | Extended Tag | 8*n | Section 3.3.3.3 |
| | | | 3.3.3.2 | | 1155 | Prefix Metric | 4 | Section 3.3.3.4 |
| 1154 | Extended Tag | 8*n | Section | | 1156 | OSPF Forwarding | 4 | Section 3.3.3.5 |
| | | | 3.3.3.3 | | | Address | | |
| 1155 | Prefix Metric | 4 | Section | | 1157 | Opaque Prefix | variable | Section 3.3.3.6 |
| | | | 3.3.3.4 | | | Attribute | | |
| 1156 | OSPF Forwarding | 4 | Section | +---------------+----------------------+----------+-----------------+
| | Address | | 3.3.3.5 |
| 1157 | Opaque Prefix | variable | Section | Table 11: Prefix Attribute TLVs
| | Attribute | | 3.3.3.6 |
+-------------+---------------------+--------------+----------------+
3.3.3.1. IGP Flags TLV 3.3.3.1. IGP Flags TLV
IGP Flags TLV contains IS-IS and OSPF flags and bits originally IGP Flags TLV contains IS-IS and OSPF flags and bits originally
assigned tothe prefix. The IGP Flags TLV is encoded as follows: assigned tothe 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|D| Reserved | |D|N|L|P| Resvd.|
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Figure 25: IGP Flag TLV format
The value field contains bits defined according to the table below: The value field contains bits defined according to the table below:
+----------+--------------------------+-----------+ +----------+---------------------------+-----------+
| Bit | Description | Reference | | Bit | Description | Reference |
+----------+--------------------------+-----------+ +----------+---------------------------+-----------+
| 'D' | IS-IS Up/Down Bit | [RFC5305] | | 'D' | IS-IS Up/Down Bit | [RFC5305] |
| Reserved | Reserved for future use. | | | 'N' | OSPF "no unicast" Bit | [RFC5340] |
+----------+--------------------------+-----------+ | 'L' | OSPF "local address" Bit | [RFC5340] |
| 'P' | OSPF "propagate NSSA" Bit | [RFC5340] |
| Reserved | Reserved for future use. | |
+----------+---------------------------+-----------+
Table 12: IGP Flag Bits Definitions
3.3.3.2. Route Tag 3.3.3.2. Route Tag
Route Tag TLV carries original IGP TAGs (IS-IS [RFC5130] or OSPF) of Route Tag TLV carries original IGP TAGs (IS-IS [RFC5130] or OSPF) of
the prefix and is encoded as follows: the 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 Tags (one or more) // // Route Tags (one or more) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 26: IGP Route TAG TLV format
Length is a multiple of 4. Length is a multiple of 4.
The value field contains one or more Route Tags as learned in the IGP The value field contains one or more Route Tags as learned in the IGP
topology. topology.
3.3.3.3. Extended Route Tag 3.3.3.3. Extended Route Tag
Extended Route Tag TLV carries IS-IS Extended Route TAGs of the Extended Route Tag TLV carries IS-IS Extended Route TAGs of the
prefix [RFC5130] and is encoded as follows: prefix [RFC5130] 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 (one or more) // // Extended Route Tag (one or more) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 27: Extended IGP Route TAG TLV format
Length is a multiple of 8. Length is a multiple of 8.
The 'Extended Route Tag' field contains one or more Extended Route The 'Extended Route Tag' field contains one or more Extended Route
Tags as learned in the IGP topology. Tags as 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 is an optional attribute and may only appear once.
IGP topology [RFC5305]. The attribute is mandatory and can only If present, it carries the metric of the prefix as known in the IGP
appear once. topology [RFC5305] (and therefore represents the reachability cost to
the prefix). If not present, it means that the prefix is advertised
without any reachability.
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 28: Prefix Metric TLV Format
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 [RFC2328] carries the OSPF forwarding OSPF Forwarding Address TLV [RFC2328] and [RFC5340] carries the OSPF
address as known in the original OSPF advertisement. Forwarding forwarding address as known in the original OSPF advertisement.
address can be either IPv4 or IPv6. Forwarding address can be 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 29: OSPF Forwarding Address TLV Format
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.
3.3.3.6. Opaque Prefix Attribute TLV 3.3.3.6. Opaque Prefix Attribute TLV
The Opaque Prefix attribute TLV is an envelope that transparently The Opaque Prefix Attribute TLV is an envelope that transparently
carries optional prefix attribute TLVs advertised by a router. An carries optional prefix attribute TLVs advertised by a router. An
originating router shall use this TLV for encoding information originating router shall use this TLV for encoding information
specific to the protocol advertised in the NLRI header Protocol-ID specific to the protocol advertised in the NLRI header Protocol-ID
field or new protocol extensions to the protocol as advertised in the field or new protocol extensions to the protocol as advertised in the
NLRI header Protocol-ID field for which there is no protocol neutral NLRI header Protocol-ID field for which there is no protocol neutral
representation in the BGP link-state NLRI. representation in the BGP link-state NLRI. The primary use of the
Opaque Prefix Attribute TLV is to bridge the document lag between
e.g. a new IGP Link-state attribute being defined and the 'protocol-
neutral' BGP-LS extensions being published.
The format of the TLV is as follows: The format of the TLV is 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 |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
// Opaque Prefix Attributes (variable) // // Opaque Prefix Attributes (variable) //
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Type is as specified in Table 9 and Length is variable.
Figure 30: Opaque Prefix Attribute TLV Format
Type is as specified in Table 11 and Length is variable.
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 an 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 an IPv6 BGP session is
then the next hop in the MP_REACH_NLRI SHOULD be an IPv6 address. used, then the next hop in the MP_REACH_NLRI SHOULD be an IPv6
Usually the next hop will be set to the local end-point address of address. Usually the next hop will be set to the local end-point
the BGP session. The next hop address MUST be encoded as described address of the BGP session. The next hop address MUST be encoded as
in [RFC4760]. The length field of the next hop address will specify described in [RFC4760]. The length field of the next hop address
the next hop address-family. If the next hop length is 4, then the will specify the next hop address-family. If the next hop length is
next hop is an IPv4 address; if the next hop length is 16, then it is 4, then the next hop is an IPv4 address; if the next hop length is
a global IPv6 address and if the next hop length is 32, then there is 16, then it is a global IPv6 address and if the next hop length is
one global IPv6 address followed by a link-local IPv6 address. The 32, then there is one global IPv6 address followed by a link-local
link-local IPv6 address should be used as described in [RFC2545]. IPv6 address. The link-local IPv6 address should be used as
For VPN SAFI, as per custom, an 8 byte route-distinguisher set to all described in [RFC2545]. For VPN SAFI, as per custom, an 8 byte
zero is prepended to the next hop. route-distinguisher set to all zero is prepended to the next hop.
The BGP Next Hop attribute is used by each BGP-LS speaker to validate The BGP Next Hop attribute is used by each BGP-LS speaker to validate
the NLRI it receives. However, this specification doesn't mandate the NLRI it receives. In case identical NLRIs are sourced by
any rule regarding the re-write of the BGP Next Hop attribute. multiple originators the BGP next hop attribute is used to tie-break
as per the standard BGP path decision process. 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 some cases, the IGP may have information of inter-AS links. In some cases, the IGP may have information of
inter-AS links ([RFC5392], [RFC5316]). In other cases, an inter-AS links ([RFC5392], [RFC5316]). In other cases, an
implementation SHOULD provide a means to inject inter-AS links into implementation SHOULD provide a means to inject inter-AS links into
BGP-LS. The exact mechanism used to provision the inter-AS links is BGP-LS. The exact mechanism used to provision the inter-AS links is
outside the scope of this document outside the scope of this document
3.6. Router-ID Anchoring Example: ISO Pseudonode 3.6. Router-ID Anchoring Example: ISO Pseudonode
Encoding of a broadcast LAN in IS-IS provides a good example of how Encoding of a broadcast LAN in IS-IS provides a good example of how
Router-IDs are encoded. Consider Figure 31. This represents a Router-IDs are encoded. Consider Figure 31. This represents a
Broadcast LAN between a pair of routers. The "real" (=non Broadcast LAN between a pair of routers. The "real" (=non
pseudonode) routers have both an IPv4 Router-ID and IS-IS Node-ID. pseudonode) routers have both an IPv4 Router-ID and IS-IS Node-ID.
The pseudonode does not have an IPv4 Router-ID. Node1 is the DIS for The pseudonode does not have an IPv4 Router-ID. Node1 is the DIS for
the LAN. Two unidirectional links (Node1, Pseudonode 1) and the LAN. Two unidirectional links (Node1, Pseudonode 1) and
(Pseudonode1, Node2) are being generated. (Pseudonode1, Node2) are being generated.
The link NRLI of (Node1, Pseudonode1) is encoded as follows: the IGP The link NRLI of (Node1, Pseudonode1) is encoded as follows: the IGP
Router-ID TLV of the local node descriptor is 6 octets long Router-ID TLV of the local node descriptor is 6 octets long
containing ISO-ID of Node1, 1920.0000.2001; the IGP Router-ID TLV of containing ISO-ID of Node1, 1920.0000.2001; the IGP Router-ID TLV of
the remote node descriptor is 7 octets long containing the ISO-ID of the remote node descriptor is 7 octets long containing the ISO-ID of
Pseudonode1, 1920.0000.2001.02. The BGP-LS attribute of this link Pseudonode1, 1920.0000.2001.02. The BGP-LS attribute of this link
contains one local IPv4 Router-ID TLV (TLV type 1028) containing contains one local IPv4 Router-ID TLV (TLV type 1028) containing
192.0.2.1, the IPv4 Router-ID of Node1. 192.0.2.1, the IPv4 Router-ID of Node1.
The link NRLI of (Pseudonode1. Node2) is encoded as follows: the IGP The link NRLI of (Pseudonode1. Node2) is encoded as follows: the IGP
Router-ID TLV of the local node descriptor is 7 octets long Router-ID TLV of the local node descriptor is 7 octets long
containing the ISO-ID of Pseudonode1, 1920.0000.2001.02; the IGP containing the ISO-ID of Pseudonode1, 1920.0000.2001.02; the IGP
Router-ID TLV of the remote node descriptor is 6 octets long Router-ID TLV of the remote node descriptor is 6 octets long
containing ISO-ID of Node2, 1920.0000.2002. The BGP-LS attribute of containing ISO-ID of Node2, 1920.0000.2002. The BGP-LS attribute of
this link contains one remote IPv4 Router-ID TLV (TLV type 1030) this link contains one remote IPv4 Router-ID TLV (TLV type 1030)
containing 192.0.2.2, the IPv4 Router-ID of Node2. containing 192.0.2.2, the IPv4 Router-ID of Node2.
+-----------------+ +-----------------+ +-----------------+ +-----------------+ +-----------------+ +-----------------+
| Node1 | | Pseudonode1 | | Node2 | | Node1 | | Pseudonode1 | | Node2 |
|1920.0000.2001.00|--->|1920.0000.2001.02|--->|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 |
+-----------------+ +-----------------+ +-----------------+ +-----------------+ +-----------------+ +-----------------+
3.7. Router-ID Anchoring Example: OSPFv2 to IS-IS Migration Figure 31: IS-IS Pseudonodes
3.7. Router-ID Anchoring Example: OSPF Pseudonode
Encoding of a broadcast LAN in OSPF provides a good example of how
Router-IDs and local Interface IPs are encoded. Consider Figure 32.
This represents a Broadcast LAN between a pair of routers. The
"real" (=non pseudonode) routers have both an IPv4 Router-ID and an
Area Identifier. The pseudonode does have an IPv4 Router-ID, an IPv4
interface Address (for disambiguation) and an OSPF Area. Node1 is
the DIS for the LAN, hence its local IP address 10.1.1.1 is used both
as the Router-ID and Interface IP for the Pseudonode keys. Two
unidirectional links (Node1, Pseudonode 1) and (Pseudonode1, Node2)
are being generated.
The link NRLI of (Node1, Pseudonode1) is encoded as follows:
o Local Node Descriptor
TLV #515: IGP Router ID: 11.11.11.11
TLV #514: OSPF Area-ID: ID:0.0.0.0
o Remote Node Descriptor
TLV #515: IGP Router ID: 10.1.1.1:10.1.1.1
TLV #514: OSPF Area-ID: ID:0.0.0.0
The link NRLI of (Pseudonode1, Node2) is encoded as follows:
o Local Node Descriptor
TLV #515: IGP Router ID: 10.1.1.1:10.1.1.1
TLV #514: OSPF Area-ID: ID:0.0.0.0
o Remote Node Descriptor
TLV #515: IGP Router ID: 33.33.33.34
TLV #514: OSPF Area-ID: ID:0.0.0.0
+-----------------+ +-----------------+ +-----------------+
| Node1 | | Pseudonode1 | | Node2 |
| 11.11.11.11 |--->| 10.1.1.1 |--->| 33.33.33.34 |
| | | 10.1.1.1 | | |
| Area 0 | | Area 0 | | Area 0 |
+-----------------+ +-----------------+ +-----------------+
Figure 32: OSPF Pseudonodes
3.8. Router-ID Anchoring Example: OSPFv2 to IS-IS Migration
Graceful migration from one IGP to another requires coordinated Graceful migration from one IGP to another requires coordinated
operation of both protocols during the migration period. Such a operation of both protocols during the migration period. Such a
coordination requires identifying a given physical link in both IGPs. coordination requires identifying a given physical link in both IGPs.
The IPv4 Router-ID provides that "glue" which is present in the node The IPv4 Router-ID provides that "glue" which is present in the node
descriptors of the OSPF link NLRI and in the link attribute of the descriptors of the OSPF link NLRI and in the link attribute of the
IS-IS link NLRI. IS-IS link NLRI.
Consider a point-to-point link between two routers, A and B, that Consider a point-to-point link between two routers, A and B, that
initially were OSPFv2-only routers and then IS-IS is enabled on them. initially were OSPFv2-only routers and then IS-IS is enabled on them.
Node A has IPv4 Router-ID and ISO-ID; node B has IPv4 Router-ID, IPv6 Node A has IPv4 Router-ID and ISO-ID; node B has IPv4 Router-ID, IPv6
Router-ID and ISO-ID. Each protocol generates one link NLRI for the Router-ID and ISO-ID. Each protocol generates one link NLRI for the
link (A, B), both of which are carried by BGP-LS. The OSPFv2 link link (A, B), both of which are carried by BGP-LS. The OSPFv2 link
NLRI for the link is encoded with the IPv4 Router-ID of nodes A and B NLRI for the link is encoded with the IPv4 Router-ID of nodes A and B
in the local and remote node descriptors, respectively. The IS-IS in the local and remote node descriptors, respectively. The IS-IS
link NLRI for the link is encoded with the ISO-ID of nodes A and B in link NLRI for the link is encoded with the ISO-ID of nodes A and B in
the local and remote node descriptors, respectively. In addition, the local and remote node descriptors, respectively. In addition,
the BGP-LS attribute of the IS-IS link NLRI contains the the TLV type the BGP-LS attribute of the IS-IS link NLRI contains the TLV type
1028 containing the IPv4 Router-ID of node A; TLV type 1030 1028 containing the IPv4 Router-ID of node A; TLV type 1030
containing the IPv4 Router-ID of node B and TLV type 1031 containing containing the IPv4 Router-ID of node B and TLV type 1031 containing
the IPv6 Router-ID of node B. In this case, by using IPv4 Router-ID, the IPv6 Router-ID of node B. In this case, by using IPv4 Router-ID,
the link (A, B) can be identified in both IS-IS and OSPF protocol. the link (A, B) can be identified in both IS-IS and OSPF protocol.
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
certainly possible, however not desirable from a scaling and privacy certainly possible, however not desirable from a scaling and privacy
point of view. Therefore an implementation may support link to path point of view. Therefore an implementation may support link to path
aggregation. Rather than advertising all specific links of a domain, aggregation. Rather than advertising all specific links of a domain,
an ASBR may advertise an "aggregate link" between a non-adjacent pair an ASBR may advertise an "aggregate link" between a non-adjacent pair
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 are discussed. examples are discussed.
4.1. Example: No Link Aggregation 4.1. Example: No Link Aggregation
Consider Figure 32. Both AS1 and AS2 operators want to protect their Consider Figure 33. 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 BGP path to R3. Therefore the AS2 operator exposes its topology. All
TE enabled routers in AS1 "see" the full topology of AS and therefore BGP TE enabled routers in AS1 "see" the full topology of AS and
can compute a backup path. Note that the decision if the direct link therefore can compute a backup path. Note that the decision if the
between {R3, R4} or the {R4, R5, R3) path is used is made by the direct link between {R3, R4} or the {R4, R5, R3) path is used is made
computing router. by the computing router.
AS1 : AS2 AS1 : AS2
: :
R1-------R3 R1-------R3
| : | \ | : | \
| : | R5 | : | R5
| : | / | : | /
R2-------R4 R2-------R4
: :
: :
Figure 33: 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 Figure this example is that no specific link gets exposed. Consider
33. The only link which gets advertised by AS2 is an "aggregate" link Figure 34. The only link which gets advertised by AS2 is an
between R3 and R4. This is enough to tell AS1 that there is a backup "aggregate" link between R3 and R4. This is enough to tell AS1 that
path. However the actual links being used are hidden from the there is a backup path. However the actual links being used are
topology. hidden from the topology.
AS1 : AS2 AS1 : AS2
: :
R1-------R3 R1-------R3
| : | | : |
| : | | : |
| : | | : |
R2-------R4 R2-------R4
: :
: :
Figure 34: 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 34. AS3 is expose their internal inter-AS links. Consider Figure 35. AS3 is
modeled as a single node which connects to the border routers of the modeled as a single 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 35: 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. As per early allocation procedure this is AFI 16388. Family Numbers. As per early allocation procedure this is AFI 16388.
This document requests a code point from the registry of Subsequent This document requests a code point from the registry of Subsequent
Address Family Numbers. As per early allocation procedure this is Address Family Numbers. As per early allocation procedure this is
SAFI 71. SAFI 71.
This document requests a code point from the BGP Path Attributes This document requests a code point from the BGP Path Attributes
registry. registry. As per early allocation procedure this is Path Attribute
29.
This document requests creation of a new registry for BGP-LS NLRI-
Types. Value 0 is reserved. The registry will be initialized as
shown in Table 1. Allocations within the registry will require
documentation of the proposed use of the allocated value and approval
by the Designated Expert assigned by the IESG (see [RFC5226]).
This document requests creation of a new registry for BGP-LS
Protocol-IDs. Value 0 is reserved. The registry will be initialized
as shown in Table 2. Allocations within the registry will require
documentation of the proposed use of the allocated value and approval
by the Designated Expert assigned by the IESG (see [RFC5226]).
This document requests creation of a new registry for BGP-LS Well-
known Instance-IDs. The registry will be initialized as shown in
Table 3. Allocations within the registry will require documentation
of the proposed use of the allocated value and approval by the
Designated Expert assigned by the IESG (see [RFC5226]).
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 11. Allocations within the registry initialized as shown in Table 13. Allocations within the registry
will require documentation of the proposed use of the allocated value will require documentation of the proposed use of the allocated value
and approval by the Designated Expert assigned by the IESG (see and approval by the Designated Expert assigned by the IESG (see
[RFC5226]). [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 32, line 7 skipping to change at page 37, line 46
TBD. TBD.
6.2.3. Configuration Management 6.2.3. Configuration Management
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
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 64-bit An implementation SHOULD allow the operator to configure a 64-bit
instance ID. instance ID.
An implementation SHOULD allow the operator to configure a pair of An implementation SHOULD allow the operator to configure a pair of
ASN and BGP-LS identifier per flooding set the node participates in. ASN and BGP-LS identifier (Paragraph 2) per flooding set in which the
node participates.
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 33, line 5 skipping to change at page 38, line 43
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. TLV/Sub-TLV Code Points Summary 7. TLV/Sub-TLV Code Points Summary
This section contains the global table of all TLVs/Sub-TLVs defined This section contains the global table of all TLVs/Sub-TLVs defined
in this document. in this document.
+---------+----------------------+--------------+-------------------+ +-----------+---------------------+---------------+-----------------+
| TLV | Description | IS-IS TLV/ | Value defined in: | | TLV Code | Description | IS-IS TLV/ | Value defined |
| Code | | Sub-TLV | | | Point | | Sub-TLV | in: |
| Point | | | | +-----------+---------------------+---------------+-----------------+
+---------+----------------------+--------------+-------------------+ | 256 | Local Node | --- | Section 3.2.1.2 |
| 256 | Local Node | --- | Section 3.2.1.2 | | | Descriptors | | |
| | Descriptors | | | | 257 | Remote Node | --- | Section 3.2.1.3 |
| 257 | Remote Node | --- | Section 3.2.1.3 | | | Descriptors | | |
| | Descriptors | | | | 258 | Link Local/Remote | 22/4 | [RFC5307]/1.1 |
| 258 | Link Local/Remote | 22/4 | [RFC5307]/1.1 | | | Identifiers | | |
| | Identifiers | | | | 259 | IPv4 interface | 22/6 | [RFC5305]/3.2 |
| 259 | IPv4 interface | 22/6 | [RFC5305]/3.2 | | | address | | |
| | address | | | | 260 | IPv4 neighbor | 22/8 | [RFC5305]/3.3 |
| 260 | IPv4 neighbor | 22/8 | [RFC5305]/3.3 | | | address | | |
| | address | | | | 261 | IPv6 interface | 22/12 | [RFC6119]/4.2 |
| 261 | IPv6 interface | 22/12 | [RFC6119]/4.2 | | | address | | |
| | address | | | | 262 | IPv6 neighbor | 22/13 | [RFC6119]/4.3 |
| 262 | IPv6 neighbor | 22/13 | [RFC6119]/4.3 | | | address | | |
| | address | | | | 263 | Multi-Topology ID | --- | Section 3.2.1.5 |
| 263 | Multi-Topology ID | --- | Section 3.2.1.5 | | 264 | OSPF Route Type | --- | Section 3.2.3 |
| 264 | OSPF Route Type | --- | Section 3.2.3 | | 265 | IP Reachability | --- | Section 3.2.3 |
| 265 | IP Reachability | --- | Section 3.2.3 | | | Information | | |
| | Information | | | | 512 | Autonomous System | --- | Section 3.2.1.4 |
| 512 | Autonomous System | --- | Section 3.2.1.4 | | 513 | BGP-LS Identifier | --- | Section 3.2.1.4 |
| 513 | BGP-LS Identifier | --- | Section 3.2.1.4 | | 514 | OSPF Area ID | --- | Section 3.2.1.4 |
| 514 | Area ID | --- | Section 3.2.1.4 | | 515 | IGP Router-ID | --- | Section 3.2.1.4 |
| 515 | IGP Router-ID | --- | Section 3.2.1.4 | | 1024 | Node Flag Bits | --- | Section 3.3.1.1 |
| 1024 | Node Flag Bits | --- | Section 3.3.1.1 | | 1025 | Opaque Node | --- | Section 3.3.1.5 |
| 1025 | Opaque Node | --- | Section 3.3.1.5 | | | Properties | | |
| | Properties | | | | 1026 | Node Name | variable | Section 3.3.1.3 |
| 1026 | Node Name | variable | Section 3.3.1.3 | | 1027 | IS-IS Area | variable | Section 3.3.1.2 |
| 1027 | IS-IS Area | variable | Section 3.3.1.2 | | | Identifier | | |
| | Identifier | | | | 1028 | IPv4 Router-ID of | 134/--- | [RFC5305]/4.3 |
| 1028 | IPv4 Router-ID of | 134/--- | [RFC5305]/4.3 | | | Local Node | | |
| | Local Node | | | | 1029 | IPv6 Router-ID of | 140/--- | [RFC6119]/4.1 |
| 1029 | IPv6 Router-ID of | 140/--- | [RFC6119]/4.1 | | | Local Node | | |
| | Local Node | | | | 1030 | IPv4 Router-ID of | 134/--- | [RFC5305]/4.3 |
| 1030 | IPv4 Router-ID of | 134/--- | [RFC5305]/4.3 | | | Remote Node | | |
| | Remote Node | | | | 1031 | IPv6 Router-ID of | 140/--- | [RFC6119]/4.1 |
| 1031 | IPv6 Router-ID of | 140/--- | [RFC6119]/4.1 | | | Remote Node | | |
| | Remote Node | | | | 1032 | Link Local/Remote | 22/4 | [RFC5307]/1.1 |
| 1032 | Link Local/Remote | 22/4 | [RFC5307]/1.1 | | | Identifiers | | |
| | Identifiers | | | | 1088 | Administrative | 22/3 | [RFC5305]/3.1 |
| 1088 | Administrative group | 22/3 | [RFC5305]/3.1 | | | group (color) | | |
| | (color) | | | | 1089 | Maximum link | 22/9 | [RFC5305]/3.3 |
| 1089 | Maximum link | 22/9 | [RFC5305]/3.3 | | | bandwidth | | |
| | bandwidth | | | | 1090 | Max. reservable | 22/10 | [RFC5305]/3.5 |
| 1090 | Max. reservable link | 22/10 | [RFC5305]/3.5 | | | link bandwidth | | |
| | bandwidth | | | | 1091 | Unreserved | 22/11 | [RFC5305]/3.6 |
| 1091 | Unreserved bandwidth | 22/11 | [RFC5305]/3.6 | | | bandwidth | | |
| 1092 | TE Default Metric | 22/18 | Section 3.3.2.3 | | 1092 | TE Default Metric | 22/18 | Section 3.3.2.3 |
| 1093 | Link Protection Type | 22/20 | [RFC5307]/1.2 | | 1093 | Link Protection | 22/20 | [RFC5307]/1.2 |
| 1094 | MPLS Protocol Mask | --- | Section 3.3.2.2 | | | Type | | |
| 1095 | IGP Metric | --- | Section 3.3.2.4 | | 1094 | MPLS Protocol Mask | --- | Section 3.3.2.2 |
| 1096 | Shared Risk Link | --- | Section 3.3.2.5 | | 1095 | IGP Metric | --- | Section 3.3.2.4 |
| | Group | | | | 1096 | Shared Risk Link | --- | Section 3.3.2.5 |
| 1097 | Opaque link | --- | Section 3.3.2.6 | | | Group | | |
| | attribute | | | | 1097 | Opaque link | --- | Section 3.3.2.6 |
| 1098 | Link Name attribute | --- | Section 3.3.2.7 | | | attribute | | |
| 1152 | IGP Flags | --- | Section 3.3.3.1 | | 1098 | Link Name attribute | --- | Section 3.3.2.7 |
| 1153 | Route Tag | --- | [RFC5130] | | 1152 | IGP Flags | --- | Section 3.3.3.1 |
| 1154 | Extended Tag | --- | [RFC5130] | | 1153 | Route Tag | --- | [RFC5130] |
| 1155 | Prefix Metric | --- | [RFC5305] | | 1154 | Extended Tag | --- | [RFC5130] |
| 1156 | OSPF Forwarding | --- | [RFC2328] | | 1155 | Prefix Metric | --- | [RFC5305] |
| | Address | | | | 1156 | OSPF Forwarding | --- | [RFC2328] |
| 1157 | Opaque Prefix | --- | Section 3.3.3.6 | | | Address | | |
| | Attribute | | | | 1157 | Opaque Prefix | --- | Section 3.3.3.6 |
+---------+----------------------+--------------+-------------------+ | | Attribute | | |
+-----------+---------------------+---------------+-----------------+
Table 13: Summary Table of TLV/Sub-TLV Codepoints
8. Security Considerations 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. See the 'Security Considerations' affect the BGP security model. See the 'Security Considerations'
section of [RFC4271] for a discussion of BGP security. Also refer to section of [RFC4271] for a discussion of BGP security. Also refer to
[RFC4272] and [RFC6952] for analysis of security issues for BGP. [RFC4272] and [RFC6952] for analysis of security issues for BGP.
In the context of the BGP peerings associated with this document, a In the context of the BGP peerings associated with this document, a
BGP Speaker SHOULD NOT accept updates from a Consumer peer. That is, BGP Speaker SHOULD NOT accept updates from a Consumer peer. That is,
a participating BGP Speaker, should be aware of the nature of its a participating BGP Speaker, should be aware of the nature of its
relationships for link state relationships and should protect itself relationships for link state relationships and should protect itself
from peers sending updates that either represent erroneous from peers sending updates that either represent erroneous
information feedback loops, or are false input. Such protection can information feedback loops, or are false input. Such protection can
be achieved by manual configuration of Consumer peers at the BGP be achieved by manual configuration of Consumer peers at the BGP
Speaker. Speaker.
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. The principal attack a consumer against DDoS attacks from Consumers. The principal attack a consumer
may apply is to attempt to start multiple sessions either may apply is to attempt to start multiple sessions either
sequentially or simultaneously. Protection can be applied by sequentially or simultaneously. Protection can be applied by
imposing rate limits. imposing rate limits.
Additionally, it may be considered that the export of link state and Additionally, it may be considered that the export of link state and
TE information as described in this document constitutes a risk to TE information as described in this document constitutes a risk to
confidentiality of mission-critical or commercially-sensitive confidentiality of mission-critical or commercially-sensitive
information about the network. BGP peerings are not automatic and information about the network. BGP peerings are not automatic and
require configuration, thus it is the responsibility of the network require configuration, thus it is the responsibility of the network
operator to ensure that only trusted Consumers are configured to operator to ensure that only trusted Consumers are configured to
skipping to change at page 35, line 18 skipping to change at page 41, line 26
Vipin Kumar, Naiming Shen, Balaji Rajagopalan and Yakov Rekhter for Vipin Kumar, Naiming Shen, Balaji Rajagopalan and Yakov Rekhter for
their comments. their comments.
11. References 11. References
11.1. Normative 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", BCP E. Lear, "Address Allocation for Private Internets", BCP
5, RFC 1918, February 1996. 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.
[RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998. [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, April 1998.
[RFC2545] Marques, P. and F. Dupont, "Use of BGP-4 Multiprotocol [RFC2545] Marques, P. and F. Dupont, "Use of BGP-4 Multiprotocol
Extensions for IPv6 Inter-Domain Routing", RFC 2545, March Extensions for IPv6 Inter-Domain Routing", RFC 2545, March
1999. 1999.
[RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V. [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
Tunnels", RFC 3209, December 2001. Tunnels", RFC 3209, December 2001.
[RFC4202] Kompella, K. and Y. Rekhter, "Routing Extensions in [RFC4202] Kompella, K. and Y. Rekhter, "Routing Extensions in
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, January "Multiprotocol Extensions for BGP-4", RFC 4760, January
2007. 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", RFC Pillay-Esnault, "Multi-Topology (MT) Routing in OSPF", RFC
4915, June 2007. 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.
[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,
May 2008. May 2008.
[RFC5301] McPherson, D. and N. Shen, "Dynamic Hostname Exchange [RFC5301] McPherson, D. and N. Shen, "Dynamic Hostname Exchange
Mechanism for IS-IS", RFC 5301, October 2008. Mechanism for IS-IS", RFC 5301, October 2008.
[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.
[RFC5340] Coltun, R., Ferguson, D., Moy, J., and A. Lindem, "OSPF
for IPv6", RFC 5340, July 2008.
[RFC5890] Klensin, J., "Internationalized Domain Names for [RFC5890] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document Framework", Applications (IDNA): Definitions and Document Framework",
RFC 5890, August 2010. RFC 5890, August 2010.
[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.
[RFC6286] Chen, E. and J. Yuan, "Autonomous-System-Wide Unique BGP [RFC6286] Chen, E. and J. Yuan, "Autonomous-System-Wide Unique BGP
Identifier for BGP-4", RFC 6286, June 2011. Identifier for BGP-4", RFC 6286, June 2011.
[RFC6822] Previdi, S., Ginsberg, L., Shand, M., Roy, A. and D. Ward, [RFC6549] Lindem, A., Roy, A., and S. Mirtorabi, "OSPFv2 Multi-
"IS-IS Multi-Instance", RFC 6822, December 2012. Instance Extensions", RFC 6549, March 2012.
[RFC6822] Previdi, S., Ginsberg, L., Shand, M., Roy, A., and D.
Ward, "IS-IS Multi-Instance", RFC 6822, December 2012.
11.2. Informative References 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-
Internet-Draft draft-ietf-alto-protocol-27, March 2014. ietf-alto-protocol-27 (work in progress), March 2014.
[RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", RFC [RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", RFC
4272, January 2006. 4272, January 2006.
[RFC4655] Farrel, A., Vasseur, J.-P. 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.P. and J.L. 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.
[RFC5152] Vasseur, JP., Ayyangar, A. and R. Zhang, "A Per-Domain [RFC5152] Vasseur, JP., Ayyangar, A., and R. Zhang, "A Per-Domain
Path Computation Method for Establishing Inter-Domain Path Computation Method for Establishing Inter-Domain
Traffic Engineering (TE) Label Switched Paths (LSPs)", RFC Traffic Engineering (TE) Label Switched Paths (LSPs)", RFC
5152, February 2008. 5152, February 2008.
[RFC5316] Chen, M., Zhang, R. and X. Duan, "ISIS Extensions in [RFC5316] Chen, M., Zhang, R., and X. Duan, "ISIS Extensions in
Support of Inter-Autonomous System (AS) MPLS and GMPLS Support of Inter-Autonomous System (AS) MPLS and GMPLS
Traffic Engineering", RFC 5316, December 2008. Traffic Engineering", RFC 5316, December 2008.
[RFC5392] Chen, M., Zhang, R. and X. Duan, "OSPF Extensions in [RFC5392] Chen, M., Zhang, R., and X. Duan, "OSPF Extensions in
Support of Inter-Autonomous System (AS) MPLS and GMPLS Support of Inter-Autonomous System (AS) MPLS and GMPLS
Traffic Engineering", RFC 5392, January 2009. Traffic Engineering", RFC 5392, January 2009.
[RFC5693] Seedorf, J. and E. Burger, "Application-Layer Traffic [RFC5693] Seedorf, J. and E. Burger, "Application-Layer Traffic
Optimization (ALTO) Problem Statement", RFC 5693, October Optimization (ALTO) Problem Statement", RFC 5693, October
2009. 2009.
[RFC5706] Harrington, D., "Guidelines for Considering Operations and [RFC5706] Harrington, D., "Guidelines for Considering Operations and
Management of New Protocols and Protocol Extensions", RFC Management of New Protocols and Protocol Extensions", RFC
5706, November 2009. 5706, November 2009.
[RFC6549] Lindem, A., Roy, A. and S. Mirtorabi, "OSPFv2 Multi- [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of
Instance Extensions", RFC 6549, March 2012.
[RFC6952] Jethanandani, M., Patel, K. and L. Zheng, "Analysis of
BGP, LDP, PCEP, and MSDP Issues According to the Keying BGP, LDP, PCEP, and MSDP Issues According to the Keying
and Authentication for Routing Protocols (KARP) Design and Authentication for Routing Protocols (KARP) Design
Guide", RFC 6952, May 2013. Guide", RFC 6952, May 2013.
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
Email: hannes@juniper.net Email: hannes@juniper.net
Jan Medved Jan Medved
Cisco Systems, Inc. Cisco Systems, Inc.
170, West Tasman Drive 170, West Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
US US
Email: jmedved@cisco.com Email: jmedved@cisco.com
Stefano Previdi Stefano Previdi
Cisco Systems, Inc. Cisco Systems, Inc.
Via Del Serafico, 200 Via Del Serafico, 200
Rome, 00142 Rome 00142
Italy Italy
Email: sprevidi@cisco.com Email: sprevidi@cisco.com
Adrian Farrel Adrian Farrel
Juniper Networks, Inc. Juniper Networks, Inc.
1194 N. Mathilda Ave. 1194 N. Mathilda Ave.
Sunnyvale, CA 94089 Sunnyvale, CA 94089
US US
Email: afarrel@juniper.net Email: afarrel@juniper.net
Saikat Ray Saikat Ray
Cisco Systems, Inc. Cisco Systems, Inc.
170, West Tasman Drive 170, West Tasman Drive
San Jose, CA 95134 San Jose, CA 95134
US US
Email: sairay@cisco.com Email: sairay@cisco.com
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