[Docs] [txt|pdf|xml] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-petrie-grow-mrt-add-paths) 00 01 02 03 RFC 8050

Global Routing Operations                                      C. Petrie
Internet-Draft                                                  RIPE NCC
Intended status: Standards Track                                 T. King
Expires: January 9, 2017                          DE-CIX Management GmbH
                                                            July 8, 2016


 Multi-Threaded Routing Toolkit (MRT) Routing Information Export Format
                  with BGP Additional Paths Extensions
                    draft-ietf-grow-mrt-add-paths-01

Abstract

   This document updates the Multi-threaded Routing Toolkit (MRT) export
   format for Border Gateway Protocol (BGP) routing information by
   extending it to support the Advertisement of Multiple Paths in BGP
   extensions.

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 http://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 January 9, 2017.

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




Petrie & King            Expires January 9, 2017                [Page 1]


Internet-Draft     Additional Paths Extensions in MRT          July 2016


   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Requirements Language . . . . . . . . . . . . . . . . . . . .   2
   3.  Rationale . . . . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  MRT Subtypes for Types BGP4MP/BGP4MP_ET . . . . . . . . . . .   3
   5.  MRT Subtypes for Type TABLE_DUMP_V2 . . . . . . . . . . . . .   3
     5.1.  AFI/SAFI specific RIB Subtypes  . . . . . . . . . . . . .   4
     5.2.  RIB_GENERIC_ADDPATH Subtype . . . . . . . . . . . . . . .   4
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
     6.1.  BGP4MP/BGP4MP_ET Subtype codes: . . . . . . . . . . . . .   5
     6.2.  TABLE_DUMP_V2 Subtype codes:  . . . . . . . . . . . . . .   5
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   6
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   6
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   6
     8.3.  URIs  . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   7

1.  Introduction

   The MRT record format [RFC6396] was developed to provide researchers
   and engineers a means to encapsulate, export, and archive routing
   protocol transactions and routing information base snapshots.

   The Advertisement of Multiple Paths in BGP [I-D.ietf-idr-add-paths]
   defines a BGP extension to allow the advertisement of multiple paths
   for the same address prefix without the new paths implicitly
   replacing any previous ones.

   This document contains an optional extension to the MRT format
   [RFC6396] and introduces additional definitions of MRT subtype fields
   to permit representation of multiple path advertisements
   [I-D.ietf-idr-add-paths].

2.  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].








Petrie & King            Expires January 9, 2017                [Page 2]


Internet-Draft     Additional Paths Extensions in MRT          July 2016


3.  Rationale

   MRT parsers are usually stateless.  In order to parse BGP messages
   which contain data structures that depend on the capabilities
   negotiated during the BGP session setup, the so-called MRT subtypes
   are utilized.  The Advertisement of Multiple Path
   [I-D.ietf-idr-add-paths] extension for BGP alters the encoding of the
   BGP NLRI format for withdraws and announcements.  Therefore new
   BGP4MP/BGP4MP_ET subtypes as defined in [RFC6396] are required to
   signal to a MRT parser how to parse the NLRI.

   In section 4.3 [RFC6396] of the MRT specification RIB subtypes are
   specified.  Prefix length and prefix fields are encoded in the same
   manner as the BGP NLRI encoding.  In order to support path identifier
   information as defined in [I-D.ietf-idr-add-paths] new subtypes need
   to be added.

   The following two sections define the required subtypes.

4.  MRT Subtypes for Types BGP4MP/BGP4MP_ET

   This document defines the following new Subtypes:

   o  BGP4MP_MESSAGE_ADDPATH

   o  BGP4MP_MESSAGE_AS4_ADDPATH

   o  BGP4MP_MESSAGE_LOCAL_ADDPATH

   o  BGP4MP_MESSAGE_AS4_LOCAL_ADDPATH

   The fields of these message types are identical to the equivalent
   non-additional-path versions specified in section 4.4 [RFC6396].
   These enhancements continues to encapsulate the entire BGP message in
   the BGP message field.

5.  MRT Subtypes for Type TABLE_DUMP_V2

   This document defines the following new Subtypes:

   o  RIB_IPV4_UNICAST_ADDPATH

   o  RIB_IPV4_MULTICAST_ADDPATH

   o  RIB_IPV6_UNICAST_ADDPATH

   o  RIB_IPV6_MULTICAST_ADDPATH




Petrie & King            Expires January 9, 2017                [Page 3]


Internet-Draft     Additional Paths Extensions in MRT          July 2016


   o  RIB_GENERIC_ADDPATH

   The fields of these message types are identical to the equivalent
   non-additional-path versions specified in section 4.3 [RFC6396].
   However, for the specific case of the 4 AFI/SAFI specific RIB
   subtypes, the existing RIB Entries field is re-defined as detailed in
   the sections below.

5.1.  AFI/SAFI specific RIB Subtypes

   In order to preserve the record compaction achieved by using the most
   common subtypes, and allowing multiple RIB Entries to be stored in a
   single TABLE_DUMP_V2 record, the existing RIB Entries field is
   redefined for use within the new AFI/SAFI specific RIB Subtypes
   defined by this document as follows:

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |         Peer Index            |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                         Originated Time                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                         Path Identifier                       |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |      Attribute Length         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    BGP Attributes... (variable)
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

       Figure 1: RIB Entries for AFI/SAFI-specific RIB Subtypes with
                         additional-paths support

   This adds a field to the RIB Entries record, to store the path
   identifier, when used with the RIB_IPV4_UNICAST_ADDPATH,
   RIB_IPV4_MULTICAST_ADDPATH, RIB_IPV6_UNICAST_ADDPATH and
   RIB_IPV6_MULTICAST_ADDPATH subtypes.

5.2.  RIB_GENERIC_ADDPATH Subtype

   The fields of this subtype are identical to the equivalent non-
   additional-path versions specified in section 4.3.3 [RFC6396].  These
   fields continue to encapsulate the raw and additional-path enabled
   AFI/SAFI/NLRI in the record, and the raw attributes in the RIB
   Entries.

   For clarity, the RIB Entries in this subtype are not redefined.




Petrie & King            Expires January 9, 2017                [Page 4]


Internet-Draft     Additional Paths Extensions in MRT          July 2016


6.  IANA Considerations

   This document requests that IANA assign the following subtype codes
   to the MRT name space [1]:

6.1.  BGP4MP/BGP4MP_ET Subtype codes:

      BGP4MP_MESSAGE_ADDPATH = 8 (Section 4)

      BGP4MP_MESSAGE_AS4_ADDPATH = 9 (Section 4)

      BGP4MP_MESSAGE_LOCAL_ADDPATH = 10 (Section 4)

      BGP4MP_MESSAGE_AS4_LOCAL_ADDPATH = 11 (Section 4)

   The values provided above are suggested as they are used in
   implementations.

6.2.  TABLE_DUMP_V2 Subtype codes:

      RIB_IPV4_UNICAST_ADDPATH = 8 (Section 5.1)

      RIB_IPV4_MULTICAST_ADDPATH = 9 (Section 5.1)

      RIB_IPV6_UNICAST_ADDPATH = 10 (Section 5.1)

      RIB_IPV6_MULTICAST_ADDPATH = 11 (Section 5.1)

      RIB_GENERIC_ADDPATH = 12 (Section 5.2)

   The values provided above are suggested as they are used in
   implementations.

7.  Security Considerations

   It is not believed that this document adds any additional security
   considerations.

   However, the security considerations of [RFC6396] are equally
   applicable to this document, and this document permits the export of
   more detailed routing data.

   An organization that uses the MRT format to store their BGP routing
   information should be aware that supporting these extensions permits
   more detailed network path information to be stored, and should
   consider the implications of this within their environment.





Petrie & King            Expires January 9, 2017                [Page 5]


Internet-Draft     Additional Paths Extensions in MRT          July 2016


   An organization that peers with public BGP collectors, and enables
   the additional-paths capability on a peering session, should be aware
   that it is exporting not only its best paths, but potentially other
   paths within its networks.  The BGP peer should consider any and all
   implications of exposing this additional data.

8.  References

8.1.  Normative References

   [I-D.ietf-idr-add-paths]
              Walton, D., Retana, A., Chen, E., and J. Scudder,
              "Advertisement of Multiple Paths in BGP", draft-ietf-idr-
              add-paths-15 (work in progress), May 2016.

   [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>.

   [RFC6396]  Blunk, L., Karir, M., and C. Labovitz, "Multi-Threaded
              Routing Toolkit (MRT) Routing Information Export Format",
              RFC 6396, DOI 10.17487/RFC6396, October 2011,
              <http://www.rfc-editor.org/info/rfc6396>.

8.2.  Informative References

   [RFC2629]  Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
              DOI 10.17487/RFC2629, June 1999,
              <http://www.rfc-editor.org/info/rfc2629>.

   [RFC3552]  Rescorla, E. and B. Korver, "Guidelines for Writing RFC
              Text on Security Considerations", BCP 72, RFC 3552,
              DOI 10.17487/RFC3552, July 2003,
              <http://www.rfc-editor.org/info/rfc3552>.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              DOI 10.17487/RFC5226, May 2008,
              <http://www.rfc-editor.org/info/rfc5226>.

8.3.  URIs

   [1] https://www.iana.org/assignments/mrt/mrt.xhtml







Petrie & King            Expires January 9, 2017                [Page 6]


Internet-Draft     Additional Paths Extensions in MRT          July 2016


Authors' Addresses

   Colin Petrie
   RIPE NCC
   Singel 258
   Amsterdam  1016 AB
   NL

   Email: cpetrie@ripe.net


   Thomas King
   DE-CIX Management GmbH
   Lichtstrasse 43i
   Cologne  50825
   Germany

   Email: thomas.king@de-cix.net

































Petrie & King            Expires January 9, 2017                [Page 7]


Html markup produced by rfcmarkup 1.129c, available from https://tools.ietf.org/tools/rfcmarkup/