IS-IS Flood Reflection
draft-ietf-lsr-isis-flood-reflection-01

Document Type Active Internet-Draft (lsr WG)
Authors Tony Przygienda  , Chris Bowers  , Yiu Lee  , Alankar Sharma  , Russ White 
Last updated 2020-07-27
Replaces draft-lsr-isis-flood-reflection
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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
   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

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.

Copyright Notice

   Copyright (c) 2020 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
   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.  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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