Multi-Topology (MT) Routing in OSPF
RFC 4915
Document | Type |
RFC - Proposed Standard
(June 2007; No errata)
Was draft-ietf-ospf-mt (ospf WG)
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Authors | Sina Mirtorabi , Liem Nguyen , Abhay Roy , Peter Psenak , Padma Pillay-Esnault | ||
Last updated | 2018-12-20 | ||
Stream | Internent Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 4915 (Proposed Standard) | |
Action Holders |
(None)
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Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | Bill Fenner | ||
Send notices to | (None) |
Network Working Group P. Psenak Request for Comments: 4915 Cisco Systems Category: Standards Track S. Mirtorabi Force10 Networks A. Roy L. Nguyen P. Pillay-Esnault Cisco Systems June 2007 Multi-Topology (MT) Routing in OSPF Status of This Memo This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document describes an extension to Open Shortest Path First (OSPF) in order to define independent IP topologies called Multi- Topologies (MTs). The Multi-Topologies extension can be used for computing different paths for unicast traffic, multicast traffic, different classes of service based on flexible criteria, or an in- band network management topology. An optional extension to exclude selected links from the default topology is also described. Psenak, et al. Standards Track [Page 1] RFC 4915 Multi-Topology (MT) Routing in OSPF June 2007 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Differences between Multi-Topology and TOS-Based Routing . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Requirements Notation . . . . . . . . . . . . . . . . . . 3 2.2. Terms . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Base MT Functional Specifications . . . . . . . . . . . . . . 4 3.1. MT Area Boundary . . . . . . . . . . . . . . . . . . . . . 4 3.2. Adjacency for MTs . . . . . . . . . . . . . . . . . . . . 4 3.3. Sending OSPF Control Packets . . . . . . . . . . . . . . . 5 3.4. Advertising MT Adjacencies and the Corresponding IP Prefixes . . . . . . . . . . . . . . . . . . . . . . . . . 5 3.4.1. Inter-Area and External Routing . . . . . . . . . . . 5 3.5. Flushing MT Information . . . . . . . . . . . . . . . . . 6 3.6. MT SPF Computation . . . . . . . . . . . . . . . . . . . . 6 3.7. MT-ID Values . . . . . . . . . . . . . . . . . . . . . . . 6 3.8. Forwarding in MT . . . . . . . . . . . . . . . . . . . . . 6 4. Default Topology Link Exclusion Functional Specifications . . 7 4.1. Exclusion of Links in the Default Topology . . . . . . . . 7 4.2. New Area Data Structure Parameter . . . . . . . . . . . . 7 4.3. Adjacency Formation with Link Exclusion Capability . . . . 8 4.4. OSPF Control Packets Transmission over Excluded Links . . 9 4.5. OSPF LSA Advertisement and SPF Computation for Excluded Links . . . . . . . . . . . . . . . . . . . . . . 9 5. Interoperability between MT-Capable and Non-MT-Capable Routers . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 5.1. Demand Circuit Compatibility Considerations . . . . . . . 10 6. Migration from Non-MT-Area to MT-Area . . . . . . . . . . . . 10 7. MT Network Management Considerations . . . . . . . . . . . . . 11 7.1. Create Dedicated Management Topology to Include All the Nodes . . . . . . . . . . . . . . . . . . . . . . . . 11 7.2. Extend the Default Topology to All the Nodes . . . . . . . 11 8. Security Considerations . . . . . . . . . . . . . . . . . . . 11 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 12 10.1. Normative References . . . . . . . . . . . . . . . . . . . 12 10.2. Informative References . . . . . . . . . . . . . . . . . . 12 Appendix A. Acknowledgments . . . . . . . . . . . . . . . . . . . 13 Appendix B. OSPF Data Formats . . . . . . . . . . . . . . . . . . 13 B.1. Router-LSAs . . . . . . . . . . . . . . . . . . . . . . . 13 B.2. Network-LSAs . . . . . . . . . . . . . . . . . . . . . . . 15 B.3. Summary-LSAs . . . . . . . . . . . . . . . . . . . . . . . 16 B.4. AS-external-LSAs . . . . . . . . . . . . . . . . . . . . . 17 B.5. Type-7 AS-external-LSAs . . . . . . . . . . . . . . . . . 18 Psenak, et al. Standards Track [Page 2]Show full document text