Area Proxy for IS-IS
draft-ietf-lsr-isis-area-proxy-03

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Last updated 2020-08-05
Replaces draft-li-lsr-isis-area-proxy
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Internet Engineering Task Force                                    T. Li
Internet-Draft                                                   S. Chen
Intended status: Experimental                               V. Ilangovan
Expires: February 6, 2021                                Arista Networks
                                                               G. Mishra
                                                            Verizon Inc.
                                                          August 5, 2020

                          Area Proxy for IS-IS
                   draft-ietf-lsr-isis-area-proxy-03

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.

   Internet-Drafts are working documents of the Internet Engineering
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   This Internet-Draft will expire on February 6, 2021.

Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Li, et al.              Expires February 6, 2021                [Page 1]
Internet-Draft                 Area Proxy                    August 2020

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   (https://trustee.ietf.org/license-info) in effect on the date of
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   described in the Simplified BSD License.

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
   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  . . . . . . . . . . . . . . . . . .  10
       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 . . . . . . . . . . . .  11
       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 . . . . . . . . . . . . . .  13
       4.4.11. The SRv6 Locator TLV  . . . . . . . . . . . . . . . .  13
       4.4.12. Traffic Engineering Information . . . . . . . . . . .  14
       4.4.13. The Area SID  . . . . . . . . . . . . . . . . . . . .  14
   5.  Inside Edge Router Functions  . . . . . . . . . . . . . . . .  14
     5.1.  Generating L2 IIHs to Outside Routers . . . . . . . . . .  14
     5.2.  Filtering LSP information . . . . . . . . . . . . . . . .  15
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