Registry and Extensions for P-Multicast Service Interface Tunnel Attribute Flags
draft-ietf-bess-pta-flags-02

BESS Working Group                                              E. Rosen
Internet-Draft                                    Juniper Networks, Inc.
Updates: 6514 (if approved)                                     T. Morin
Intended status: Standards Track                                  Orange
Expires: August 5, 2016                                 February 2, 2016

                      Registry and Extensions for
          P-Multicast Service Interface Tunnel Attribute Flags
                    draft-ietf-bess-pta-flags-02.txt

Abstract

   The BGP-based control procedures for Multicast Virtual Private
   Networks make use of a BGP attribute known as the "P-Multicast
   Service Interface (PMSI) Tunnel" attribute.  The attribute contains a
   one-octet "Flags" field.  The purpose of this document is to
   establish an IANA registry for the assignment of the bits in this
   field.  Since the Flags field contains only eight bits, this document
   also defines a new BGP Extended Community, "Additional PMSI Tunnel
   Attribute Flags", that can be used to carry additional flags for the
   PMSI Tunnel attribute.  This document updates RFC 6514.

Status of This Memo

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   This Internet-Draft will expire on August 5, 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

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   publication of this document.  Please review these documents
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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Extending the PMSI Tunnel Attribute Flags Field . . . . . . .   2
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   3
   4.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   6.  Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   5

1.  Introduction

   A BGP attribute known as the "P-Multicast Service Interface (PMSI)
   Tunnel" attribute is defined in [RFC6514].  This attribute contains a
   one-octet of "Flags" field.  Only one flag is defined in that RFC,
   but there is now a need to define additional flags.  However, that
   RFC did not create an IANA registry for the assignment of bits in the
   Flags field.  This document creates a registry for that purpose.  In
   addition, there may be a need to define more than eight flags.
   Therefore this document defines a new BGP Extended Community,
   "Additional PMSI Tunnel Attribute Flags", that can be used to carry
   additional flags for the PMSI Tunnel attribute.  A registry is also
   created for this Extended Community, allowing IANA to assign bits
   from the Extended Community's six-octet value field.

   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 [RFC2119].

2.  Extending the PMSI Tunnel Attribute Flags Field

   In [RFC6514], only a single octet in the PMSI Tunnel attribute is
   defined to carry bit flags.  This allows eight flags, which is
   unlikely to be sufficient for all future applications.

   This document defines a new Transitive Opaque Extended Community,
   "Additional PMSI Tunnel Attribute Flags".  It also defines a new bit
   flag in the PMSI Tunnel Attribute flags field, called the "Extension"
   flag.

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   The Additional PMSI Tunnel Attribute Flags Extended Community MUST
   NOT be carried by a given BGP UPDATE message unless the following
   conditions both hold:

   o  the given BGP UPDATE message is also carrying a PMSI Tunnel
      attribute, and

   o  the Extension flag of that PMSI Tunnel attribute's Flags field is
      set.

   If a given BGP UPDATE message is carrying a PMSI Tunnel attribute,
   but is not carrying an Additional PMSI Tunnel Attribute Flags
   Extended Community, then the Extension flag in the PMSI Tunnel
   attribute MUST be clear.

   If a BGP speaker receives an UPDATE message that contains an
   Additional PMSI Tunnel Attribute Flags Extended Community, but either
   (a) that UPDATE message does not contain a PMSI Tunnel attribute, or
   (b) the Extension flag of the PMSI Tunnel attribute is not set, then
   the Extended Community SHOULD be removed and SHOULD NOT be
   redistributed.  The BGP UPDATE message MUST be processed (and if
   necessary, redistributed) as if the Extended Community had not been
   present.

   Suppose a BGP speaker receives an UPDATE message that contains a PMSI
   Tunnel attribute, but does not contain an Additional PMSI Tunnel
   Attribute Flags Extended Community.  If the Extension flag of the
   PMSI Tunnel attribute is set, then the "treat-as-withdraw" procedure
   of [RFC7606] MUST be applied.

3.  IANA Considerations

   IANA is requested to create a new registry called "P-Multicast
   Service Interface (PMSI) Tunnel Attribute Flags" in the "Border
   Gateway Protocol (BGP) Parameters" registry.

   Per [RFC6514] section 5, a PMSI Tunnel Attribute contains a "Flags"
   octet.  The Flags field is a single octet, with bits numbered, left-
   to-right, from 0 to 7.  IANA is requested to initialize the registry
   as follows:

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       Bit Position      Description                      Reference
       (left to right)
            0            unassigned
            1            Extension                        This document
            2            unassigned
            3            unassigned
            4            unassigned
            5            unassigned
            6            unassigned
            7            Leaf Information Required (L)    RFC6514

                        PMSI Tunnel Attribute Flags

   The registration procedure for this registry is Standards Action.

   IANA is also requested to assign a codepoint, from the "First Come,
   First Served" range of the Transitive Opaque Extended Community Sub-
   Types registry, for "Additional PMSI Tunnel Attribute Flags".
   [TO BE REMOVED: This registration should take place at the following
   location: http://www.iana.org/assignments/bgp-extended-communities
   /bgp-extended-communities.xhtml#trans-opaque]

   IANA is further requested to establish a registry for the bit flags
   carried in the Additional PMSI Tunnel Attribute Flags extended
   community.  The bits shall be numbered 0-47, with 0 being the most
   significant bit and 47 being the least significant bit.  The
   registration policy for this registry shall be "Standards Action".
   [TO BE REMOVED: The creation of the registry should take place at the
   following location: http://www.iana.org/assignments/bgp-extended-
   communities/bgp-extended-communities.xhtml]
   The initial registry should be as follows:

       Bit Flag          Name          Reference

        0-47            unassigned

                  Additional PMSI Tunnel Attribute Flags

4.  Acknowledgments

   The authors wish to thank Martin Vigoureux for his review of this
   document.

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5.  Security Considerations

   This document establishes an IANA registry, and defines a new
   transitive opaque Extended Community.

   Establishment of an IANA registry does not raise any security
   considerations.

   While the document defines a new Extended Community for carrying bit
   flags, it does not define any of the bit flags in that Extended
   Community.  Therefore no security considerations are raised.

6.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC6514]  Aggarwal, R., Rosen, E., Morin, T., and Y. Rekhter, "BGP
              Encodings and Procedures for Multicast in MPLS/BGP IP
              VPNs", RFC 6514, DOI 10.17487/RFC6514, February 2012,
              <http://www.rfc-editor.org/info/rfc6514>.

   [RFC7606]  Chen, E., Ed., Scudder, J., Ed., Mohapatra, P., and K.
              Patel, "Revised Error Handling for BGP UPDATE Messages",
              RFC 7606, DOI 10.17487/RFC7606, August 2015,
              <http://www.rfc-editor.org/info/rfc7606>.

Authors' Addresses

   Eric C. Rosen
   Juniper Networks, Inc.
   10 Technology Park Drive
   Westford, Massachusetts  01886
   United States

   Email: erosen@juniper.net

   Thomas Morin
   Orange
   2, avenue Pierre-Marzin
   22307 Lannion Cedex
   France

   Email: thomas.morin@orange.com

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