IS-IS Flood Reflection
draft-ietf-lsr-isis-flood-reflection-01
Network Working Group A. Przygienda
Internet-Draft C. Bowers
Intended status: Standards Track Juniper
Expires: January 28, 2021 Y. Lee
A. Sharma
Comcast
R. White
Juniper
July 27, 2020
IS-IS Flood Reflection
draft-ietf-lsr-isis-flood-reflection-01
Abstract
This document describes an optional ISIS extension that allows the
creation of IS-IS flood reflection topologies. Flood reflection
allows the creation of topologies where L1 areas provide transit
forwarding for L2 destinations within an L2 topology. It
accomplishes this by creating L2 flood reflection adjacencies within
each L1 area. The L2 flood reflection adjacencies are used to flood
L2 LSPDUs, and they are used in the L2 SPF computation. However,
they are not used for forwarding. This arrangement gives the L2
topology better scaling properties. In addition, only those routers
directly participating in flood reflection have to support the
feature. This allows for the incremental deployment of scalable L1
transit areas in an existing network, without the necessity of
upgrading other routers in the network.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
Przygienda, et al. Expires January 28, 2021 [Page 1]
Internet-Draft draft-ietf-lsr-isis-flood-reflection July 2020
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on January 28, 2021.
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Table of Contents
1. Description . . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Further Details . . . . . . . . . . . . . . . . . . . . . . . 8
3. Flood Reflection TLV . . . . . . . . . . . . . . . . . . . . 9
4. Flood Reflection Discovery Sub-TLV . . . . . . . . . . . . . 10
5. Flood Reflection Adjacency Sub-TLV . . . . . . . . . . . . . 11
6. Flood Reflection Discovery . . . . . . . . . . . . . . . . . 11
7. Flood Reflection Adjacency Formation . . . . . . . . . . . . 12
8. Redistribution of Prefixes . . . . . . . . . . . . . . . . . 13
9. Route Computation . . . . . . . . . . . . . . . . . . . . . . 13
10. Special Considerations . . . . . . . . . . . . . . . . . . . 14
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
11.1. New IS-IS TLV Codepoint . . . . . . . . . . . . . . . . 14
11.2. Sub TLVs for TLV 242 . . . . . . . . . . . . . . . . . . 15
11.3. Sub TLVs for TLV 22, 23, 25, 141, 222, and 223 . . . . . 15
12. Security Considerations . . . . . . . . . . . . . . . . . . . 15
13. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15
14. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
14.1. Informative References . . . . . . . . . . . . . . . . . 15
14.2. Normative References . . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Description
Due to the inherent properties of link-state protocols the number of
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