IS-IS Prefix Attributes for Extended IPv4 and IPv6 Reachability
RFC 7794

Document Type RFC - Proposed Standard (March 2016; No errata)
Last updated 2016-03-03
Replaces draft-ginsberg-isis-prefix-attributes
Stream IETF
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Stream WG state Submitted to IESG for Publication
Document shepherd Christian Hopps
Shepherd write-up Show (last changed 2015-11-11)
IESG IESG state RFC 7794 (Proposed Standard)
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Responsible AD Alia Atlas
Send notices to "Christian Hopps" <chopps@chopps.org>
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Internet Engineering Task Force (IETF)                  L. Ginsberg, Ed.
Request for Comments: 7794                                 Cisco Systems
Category: Standards Track                                    B. Decraene
ISSN: 2070-1721                                                   Orange
                                                              S. Previdi
                                                           Cisco Systems
                                                                   X. Xu
                                                                  Huawei
                                                             U. Chunduri
                                                                Ericsson
                                                              March 2016

    IS-IS Prefix Attributes for Extended IPv4 and IPv6 Reachability

Abstract

   This document introduces new sub-TLVs to support advertisement of
   IPv4 and IPv6 prefix attribute flags and the source router ID of the
   router that originated a prefix advertisement.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7794.

Ginsberg, et al.             Standards Track                    [Page 1]
RFC 7794                 IS-IS Prefix Attributes              March 2016

Copyright Notice

   Copyright (c) 2016 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
   (http://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.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  New Sub-TLVs for Extended Reachability TLVs . . . . . . . . .   3
     2.1.  IPv4/IPv6 Extended Reachability Attribute Flags . . . . .   4
     2.2.  IPv4/IPv6 Source Router ID  . . . . . . . . . . . . . . .   5
     2.3.  Advertising Router IDs  . . . . . . . . . . . . . . . . .   6
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     5.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

Ginsberg, et al.             Standards Track                    [Page 2]
RFC 7794                 IS-IS Prefix Attributes              March 2016

1.  Introduction

   IS-IS is a link-state routing protocol defined in [ISO10589] and
   [RFC1195].  Extensions in support of advertising new forms of
   IPv4/IPv6 prefix reachability are defined in [RFC5305], [RFC5308],
   and [RFC5120].

   There are existing use cases in which knowing additional attributes
   of a prefix is useful.

   It is useful to know whether or not an advertised prefix is directly
   connected to the advertising router.  In the case of Segment Routing
   as described in [SR], knowing whether or not a prefix is directly
   connected determines what action should be taken as regards
   processing of labels associated with an incoming packet.

   It is useful to know what addresses can be used as addresses of the
   node in support of services (e.g., Remote Loop Free Alternate (RLFA)
   endpoint).

   Current formats of the Extended Reachability TLVs for both IPv4 and
   IPv6 are fixed and do not allow the introduction of additional flags
   without backwards compatibility issues.  Therefore, this document
   defines a new sub-TLV that supports the advertisement of attribute
   flags associated with prefix advertisements.
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