Area Proxy for IS-IS
draft-li-lsr-isis-area-proxy-01

• Status
• IESG evaluation record
• IESG writeups
• Email expansions
• History

• Versions
• 00
• 01

Internet Engineering Task Force                                    T. Li
Internet-Draft                                                   S. Chen
Intended status: Standards Track                         Arista Networks
Expires: June 26, 2020                                 December 24, 2019

                          Area Proxy for IS-IS
                    draft-li-lsr-isis-area-proxy-01

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
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   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 June 26, 2020.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents

Li & Chen                 Expires June 26, 2020                 [Page 1]
Internet-Draft                 Area Proxy                  December 2019

   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   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 . . . . . . . . . . . . . . . . . . . . .   5
   3.  Inside Router Functions . . . . . . . . . . . . . . . . . . .   6
     3.1.  The Area Proxy Router Capability  . . . . . . . . . . . .   6
     3.2.  Level 2 SPF Computation . . . . . . . . . . . . . . . . .   6
   4.  Area Leader Functions . . . . . . . . . . . . . . . . . . . .   7
     4.1.  Area Leader Election  . . . . . . . . . . . . . . . . . .   7
     4.2.  Redundancy  . . . . . . . . . . . . . . . . . . . . . . .   7
     4.3.  The Area Proxy TLV  . . . . . . . . . . . . . . . . . . .   7
       4.3.1.  The Area Proxy System Id Sub-TLV  . . . . . . . . . .   8
       4.3.2.  The Area Proxy Prefix SID Sub-TLV . . . . . . . . . .   9
         4.3.2.1.  Topology  . . . . . . . . . . . . . . . . . . . .  10
         4.3.2.2.  Flags . . . . . . . . . . . . . . . . . . . . . .  10
         4.3.2.3.  The SID/Label Sub-Sub-TLV . . . . . . . . . . . .  11
     4.4.  Area 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 . . . . . . . . . . . . . .  13
   5.  Inside Edge Router Functions  . . . . . . . . . . . . . . . .  13
     5.1.  Generating L2 IIHs to Outside Routers . . . . . . . . . .  13
     5.2.  Filtering LSP information . . . . . . . . . . . . . . . .  14
   6.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .  14
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  14
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  15