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Advertising Seamless Bidirectional Forwarding Detection (S-BFD) Discriminators in IS-IS

The information below is for an old version of the document that is already published as an RFC.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 7883.
Authors Les Ginsberg , Nobo Akiya , Mach Chen
Last updated 2016-07-12 (Latest revision 2015-03-01)
Replaces draft-ginsberg-isis-sbfd-discriminator
RFC stream Internet Engineering Task Force (IETF)
Intended RFC status Proposed Standard
Additional resources Mailing list discussion
Stream WG state Submitted to IESG for Publication
Document shepherd Christian Hopps
Shepherd write-up Show Last changed 2015-11-01
IESG IESG state Became RFC 7883 (Proposed Standard)
Action Holders
Consensus boilerplate Yes
Telechat date (None)
Responsible AD Alia Atlas
Send notices to (None)
IANA IANA review state IANA OK - Actions Needed
IANA action state RFC-Ed-Ack
Networking Working Group                                     L. Ginsberg
Internet-Draft                                                  N. Akiya
Intended status: Standards Track                           Cisco Systems
Expires: September 3, 2015                                       M. Chen
                                                           March 2, 2015

               Advertising S-BFD Discriminators in IS-IS


   This document defines a means of advertising one or more S-BFD
   Discriminators using the IS-IS Router Capability TLV.

Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   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

   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 September 3, 2015.

Copyright Notice

   Copyright (c) 2015 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
   ( in effect on the date of
   publication of this document.  Please review these documents

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   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.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008.  The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.   Encoding Format  . . . . . . . . . . . . . . . . . . . . . .   2
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   3
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   4
   6.  Normative References  . . . . . . . . . . . . . . . . . . . .   4
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   [S-BFD] defines a simplified mechanism to use Bidirectional
   Forwarding Detection (BFD)[RFC5880].  This mechanism depends on
   network nodes knowing the BFD discriminators which each node in the
   network has reserved for this purpose.  Use of the Intermediate
   System to Intermediate System (IS-IS)[IS-IS] protocol is one possible
   means of advertising these discriminators.

2.  Encoding Format

   The IS-IS Router CAPABILITY TLV as defined in [RFC4971] will be used
   to advertise S-BFD discriminators.  A new sub-TLV is defined as
   described below.  S-BFD Discriminators sub-TLVs are formatted as
   specified in [RFC5305].

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                                                  No. of octets
                 | Type (to be assigned by     |     1
                 | IANA - suggested value 20)  |
                 | Length (multiple of 4)      |     1
                 | Discriminator Value(s)      |     4/Discriminator
                 :                             :

   Inclusion of the S-BFD Discriminators sub-TLV in a Router Capability
   TLV is optional.  Multiple S-BFD Discriminators sub-TLVs MAY be
   advertised by an IS.  When multiple S-BFD discriminators are
   advertised how a given discriminator is mapped to a specific use case
   is out of scope for this document.

   S-BFD discriminator advertisements MAY be flooded within an area or
   throughout the domain using the procedures specified in [RFC4971].
   The appropriate flooding scope depends on the intended use of S-BFD.
   If S-BFD use will be exclusively within a Level-1 area then area
   scope is appropriate.  If S-BFD usage will span different L1 areas
   then domain scope is appropriate.

3.  IANA Considerations

   This document requires the definition of a new sub-TLV in the Sub-
   TLVs for TLV 242 registry.  The value written below is a suggested
   value subject to assignment by IANA.

    Value  Description
    ----  ---------------------
     20    S-BFD Discriminators

4.  Security Considerations

   Security concerns for IS-IS are addressed in [IS-IS], [RFC5304], and
   [RFC5310].  Introduction of the S-BFD Discriminators sub-TLV
   introduces no new security risks for IS-IS.

   Advertisement of the S-BFD discriminators does make it possible for
   attackers to initiate S-BFD sessions using the advertised
   information.  The vulnerabilities this poses and how to mitigate them
   are discussed in the Security Considerations section of [S-BFD].

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5.  Acknowledgements

   The authors wish to thank Sam Aldrin, Manav Bhatia, and Carlos
   Pignataro for input essential to defining the needed functionality.

6.  Normative References

   [IS-IS]    "Intermediate system to Intermediate system intra-domain
              routeing information exchange protocol for use in
              conjunction with the protocol for providing the
              connectionless-mode Network Service (ISO 8473), ISO/IEC
              10589:2002, Second Edition.", Nov 2002.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4971]  Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate
              System to Intermediate System (IS-IS) Extensions for
              Advertising Router Information", RFC 4971, July 2007.

   [RFC5304]  Li, T. and R. Atkinson, "IS-IS Cryptographic
              Authentication", RFC 5304, October 2008.

   [RFC5305]  Li, T. and H. Smit, "IS-IS Extensions for Traffic
              Engineering", RFC 5305, October 2008.

   [RFC5310]  Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
              and M. Fanto, "IS-IS Generic Cryptographic
              Authentication", RFC 5310, February 2009.

   [RFC5880]  Katz, D. and D. Ward, "Bidirectional Forwarding Detection
              (BFD)", RFC 5880, June 2010.

   [S-BFD]    "Seamless Bidirectional Forwarding Detection (S-BFD),
              draft-ietf-bfd-seamless-base-04(work in progress)",
              January 2015.

Authors' Addresses

   Les Ginsberg
   Cisco Systems
   510 McCarthy Blvd.
   Milpitas, CA  95035


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   Nobo Akiya
   Cisco Systems


   Mach(Guoyi) Chen


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