Area Proxy for IS-IS
draft-ietf-lsr-isis-area-proxy-05
Internet Engineering Task Force T. Li
Internet-Draft S. Chen
Intended status: Experimental V. Ilangovan
Expires: May 22, 2021 Arista Networks
G. Mishra
Verizon Inc.
November 18, 2020
Area Proxy for IS-IS
draft-ietf-lsr-isis-area-proxy-05
Abstract
Link state routing protocols have hierarchical abstraction already
built into them. However, when lower levels are used for transit,
they must expose their internal topologies to each other, leading to
scale issues.
To avoid this, this document discusses extensions to the IS-IS
routing protocol that would allow level 1 areas to provide transit,
yet only inject an abstraction of the level 1 topology into level 2.
Each level 1 area is represented as a single level 2 node, thereby
enabling greater scale.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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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 May 22, 2021.
Copyright Notice
Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
Li, et al. Expires May 22, 2021 [Page 1]
Internet-Draft Area Proxy November 2020
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
2. Area Proxy . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Segment Routing . . . . . . . . . . . . . . . . . . . . . 6
3. Inside Router Functions . . . . . . . . . . . . . . . . . . . 6
3.1. The Area Proxy TLV . . . . . . . . . . . . . . . . . . . 6
3.2. Level 2 SPF Computation . . . . . . . . . . . . . . . . . 7
3.3. Responsibilities with respect to the Proxy LSP . . . . . 8
4. Area Leader Functions . . . . . . . . . . . . . . . . . . . . 8
4.1. Area Leader Election . . . . . . . . . . . . . . . . . . 8
4.2. Redundancy . . . . . . . . . . . . . . . . . . . . . . . 8
4.3. Distributing Area Proxy Information . . . . . . . . . . . 8
4.3.1. The Area Proxy System Id Sub-TLV . . . . . . . . . . 8
4.3.2. The Area SID Sub-TLV . . . . . . . . . . . . . . . . 9
4.4. Proxy LSP Generation . . . . . . . . . . . . . . . . . . 11
4.4.1. The Protocols Supported TLV . . . . . . . . . . . . . 11
4.4.2. The Area Address TLV . . . . . . . . . . . . . . . . 11
4.4.3. The Dynamic Hostname TLV . . . . . . . . . . . . . . 11
4.4.4. The IS Neighbors TLV . . . . . . . . . . . . . . . . 11
4.4.5. The Extended IS Neighbors TLV . . . . . . . . . . . . 12
4.4.6. The MT Intermediate Systems TLV . . . . . . . . . . . 12
4.4.7. Reachability TLVs . . . . . . . . . . . . . . . . . . 12
4.4.8. The Router Capability TLV . . . . . . . . . . . . . . 13
4.4.9. The Multi-Topology TLV . . . . . . . . . . . . . . . 13
4.4.10. The SID/Label Binding and The Multi-Topology
SID/Label Binding SID TLV . . . . . . . . . . . . . . 14
4.4.11. The SRv6 Locator TLV . . . . . . . . . . . . . . . . 14
4.4.12. Traffic Engineering Information . . . . . . . . . . . 14
4.4.13. The Area SID . . . . . . . . . . . . . . . . . . . . 14
5. Inside Edge Router Functions . . . . . . . . . . . . . . . . 15
5.1. Generating L2 IIHs to Outside Routers . . . . . . . . . . 15
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