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

Versions: 00 01 02 03 04 05 draft-ietf-idr-bgp-prefix-sid

IDR                                                             K. Patel
Internet-Draft                                                S. Previdi
Intended status: Standards Track                             C. Filsfils
Expires: January 21, 2016                                 A. Sreekantiah
                                                           Cisco Systems
                                                                  S. Ray
                                                            Unaffiliated
                                                              H. Gredler
                                                        Juniper Networks
                                                           July 20, 2015


             Segment Routing Prefix SID extensions for BGP
                  draft-keyupate-idr-bgp-prefix-sid-05

Abstract

   Segment Routing (SR) architecture allows a node to steer a packet
   flow through any topological path and service chain by leveraging
   source routing.  The ingress node prepends a SR header to a packet
   containing a set of "segments".  Each segment represents a
   topological or a service-based instruction.  Per-flow state is
   maintained only at the ingress node of the SR domain.

   This document describes the BGP extension for announcing BGP Prefix
   Segment Identifier (BGP Prefix SID) information.

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]
   only when they appear in all upper case.  They may also appear in
   lower or mixed case as English words, without any normative meaning.

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




Patel, et al.           Expires January 21, 2016                [Page 1]


Internet-Draft                                                 July 2015


   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 21, 2016.

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
   (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.  Segment Routing Documents . . . . . . . . . . . . . . . . . .   3
   2.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  BGP-Prefix-SID  . . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  MPLS Prefix Segment . . . . . . . . . . . . . . . . . . .   4
     3.2.  IPv6 Prefix Segment . . . . . . . . . . . . . . . . . . .   5
   4.  BGP-Prefix-SID Attribute  . . . . . . . . . . . . . . . . . .   5
     4.1.  Label-Index TLV . . . . . . . . . . . . . . . . . . . . .   6
     4.2.  IPv6 SID  . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.3.  Originator SRGB TLV . . . . . . . . . . . . . . . . . . .   7
   5.  Receiving BGP-Prefix-SID Attribute  . . . . . . . . . . . . .   9
     5.1.  MPLS Dataplane: Labeled Unicast . . . . . . . . . . . . .   9
     5.2.  IPv6 Dataplane  . . . . . . . . . . . . . . . . . . . . .  10
   6.  Announcing BGP-Prefix-SID Attribute . . . . . . . . . . . . .  10
     6.1.  MPLS Dataplane: Labeled Unicast . . . . . . . . . . . . .  10
     6.2.  IPv6 Dataplane  . . . . . . . . . . . . . . . . . . . . .  11
   7.  Error Handling of BGP-Prefix-SID Attribute  . . . . . . . . .  11
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  12
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  12
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  12
   11. Change Log  . . . . . . . . . . . . . . . . . . . . . . . . .  12
   12. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     12.1.  Normative References . . . . . . . . . . . . . . . . . .  12
     12.2.  Informative References . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14





Patel, et al.           Expires January 21, 2016                [Page 2]


Internet-Draft                                                 July 2015


1.  Segment Routing Documents

   The main references for this document are the SR architecture defined
   in [I-D.ietf-spring-segment-routing] and the related use case
   illustrated in [I-D.filsfils-spring-segment-routing-msdc].

   The Segment Routing Egress Peer Engineering architecture is described
   in [I-D.filsfils-spring-segment-routing-central-epe].

   The Segment Routing Egress Peer Engineering BGPLS extensions are
   described in [I-D.ietf-idr-bgpls-segment-routing-epe].

2.  Introduction

   Segment Routing (SR) architecture leverages the source routing
   paradigm.  A group of inter-connected nodes that use SR forms a SR
   domain.  The ingress node of the SR domain prepends a SR header
   containing "segments" to an incoming packet.  Each segment represents
   a topological instruction such as "go to prefix P following shortest
   path" or a service instruction (e.g.: "pass through deep packet
   inspection").  By inserting the desired sequence of instructions, the
   ingress node is able to steer a packet via any topological path and/
   or service chain; per-flow state is maintained only at the ingress
   node of the SR domain.

   Each segment is identified by a Segment Identifier (SID).  As
   described in [I-D.ietf-spring-segment-routing], when SR is applied to
   the MPLS dataplane the SID consists of a label while when SR is
   applied to the IPv6 dataplane the SID consists of an IPv6 prefix (see
   [I-D.previdi-6man-segment-routing-header]).

   A BGP-Prefix Segment (aka BGP-Prefix-SID), is a BGP segment attached
   to a BGP prefix.  A BGP-Prefix-SID is always global within the SR/BGP
   domain and identifies an instruction to forward the packet over the
   ECMP-aware best-path computed by BGP to the related prefix.  The BGP-
   Prefix-SID is the identifier of the BGP prefix segment.

   This document describes the BGP extension to signal the BGP-Prefix-
   SID.  Specifically, this document defines a new BGP attribute known
   as the BGP Prefix SID attribute and specifies the rules to originate,
   receive and handle error conditions of the new attribute.

   As described in [I-D.filsfils-spring-segment-routing-msdc], the newly
   proposed BGP Prefix-SID attribute can be attached to prefixes from
   AFI/SAFI:

      Multiprotocol BGP labeled IPv4/IPv6 Unicast ([RFC3107]).




Patel, et al.           Expires January 21, 2016                [Page 3]


Internet-Draft                                                 July 2015


      Multiprotocol BGP ([RFC4760]) unlabeled IPv6 Unicast.

   [I-D.filsfils-spring-segment-routing-msdc] describes use cases where
   the Prefix-SID is used for the above AFI/SAFI.

3.  BGP-Prefix-SID

   The BGP-Prefix-SID attached to a BGP prefix P represents the
   instruction "go to Prefix P" along its BGP bestpath (potentially
   ECMP-enabled).

3.1.  MPLS Prefix Segment

   The BGP Prefix Segment is realized on the MPLS dataplane in the
   following way:

      According to [I-D.ietf-spring-segment-routing], each BGP speaker
      is configured with a label block called the Segment Routing Global
      Block (SRGB).  The SRGB of a node is a local property and could be
      different on different speakers.

      As described in [I-D.filsfils-spring-segment-routing-msdc] the
      operator assigns a globally unique "index", L_I, to a locally
      sourced prefix of a BGP speaker N which is advertised to all other
      BGP speakers in the SR domain.

      The index L_I is a 32 bit offset in the SRGB.  Each BGP speaker
      derives its local MPLS label, L, by adding L_I to the start value
      of its own SRGB, and programs L in its MPLS dataplane as its
      incoming/local label for the prefix.

      If the BGP speakers are configured with the same SRGB start value,
      they will all program the same MPLS label for a given prefix P.
      This has the effect of having a single label for prefix P across
      all BGP speakers despite that the MPLS paradigm of "local label"
      is preserved and this clearly simplifies the deployment and
      operations of traffic engineering in BGP driven networks, as
      described in [I-D.filsfils-spring-segment-routing-msdc].

   If the BGP speakers cannot be configured with the same SRGB, the
   proposed BGP Prefix-SID attribute allows the advertisement of the
   SRGB so each node can advertise the SRGB it's configured with.  The
   drawbacks of the use case where BGP speakers have different SRGBs are
   documented in [I-D.filsfils-spring-segment-routing-msdc].

   In order to advertise the label index of a given prefix P and,
   optionally, the SRGB, a new extension to BGP is needed: the BGP




Patel, et al.           Expires January 21, 2016                [Page 4]


Internet-Draft                                                 July 2015


   Prefix SID attribute.  This extension is described in subsequent
   sections.

3.2.  IPv6 Prefix Segment

   As defined in [I-D.previdi-6man-segment-routing-header], in SR for
   the IPv6 dataplane, the SRGB consists of the set of IPv6 addresses
   used within the SR domain (as described in
   [I-D.previdi-6man-segment-routing-header]).  Therefore the BGP
   speaker willing to process SR IPv6 packets MUST advertise an IPv6
   prefix with the attached Prefix SID attribute and related SR IPv6
   flag (see subsequent section).

   As described in [I-D.filsfils-spring-segment-routing-msdc], when SR
   is used over an IPv6 dataplane, the BGP Prefix Segment is
   instantiated by an IPv6 prefix originated by the BGP speaker.

   Each node advertises a globally unique IPv6 address representing
   itself in the domain.  This prefix (e.g.: its loopback interface
   address) is advertised to all other BGP speakers in the SR domain.

   Also, each node MUST advertise its support of Segment Routing for
   IPv6 dataplane.  This is realized using the Prefix SID Attribute
   defined below.

4.  BGP-Prefix-SID Attribute

   The BGP Prefix SID attribute is an optional, transitive BGP path
   attribute.  The attribute type code is to be assigned by IANA
   (suggested value: 40).  The value field of the BGP-Prefix-SID
   attribute has the following format:

   The value field of the BGP Prefix SID attribute is defined here to be
   a set of elements encoded as "Type/Length/Value" (i.e., a set of
   TLVs).  Following TLVs are defined:

   o  Label-Index TLV

   o  IPv6 SID TLV

   o  Originator SRGB TLV

   Label-Index and Originator SRGB TLVs are used only when SR is applied
   to the MPLS dataplane.

   IPv6 SID TLV is used only when SR is applied to the IPv6 dataplane.





Patel, et al.           Expires January 21, 2016                [Page 5]


Internet-Draft                                                 July 2015


4.1.  Label-Index TLV

   The Label-Index TLV MUST be present in the Prefix-SID attribute
   attached to Labeled IPv4/IPv6 unicast prefixes ([RFC3107]) and has
   the following format:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Type    |             Length            |   RESERVED    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Flags              |       Label Index             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          Label Index          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   where:

   o  Type is 1.

   o  Length: is 7, the total length of the value portion of the TLV.

   o  RESERVED: 8 bit field.  SHOULD be 0 on transmission and MUST be
      ignored on reception.

   o  Flags: 16 bits of flags.  None are defined at this stage of the
      document.  The flag field SHOULD be clear on transmission and MUST
      be ignored at reception.

   o  Label Index: 32 bit value representing the index value in the SRGB
      space.

4.2.  IPv6 SID

   The Label-Index TLV MUST be present in the Prefix-SID attribute
   attached to MP-BGP unlabeled IPv6 unicast prefixes ([RFC4760]) and
   has the following format:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Type    |             Length            |   RESERVED    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |            Flags              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   where:




Patel, et al.           Expires January 21, 2016                [Page 6]


Internet-Draft                                                 July 2015


   o  Type is 2.

   o  Length: is 3, the total length of the value portion of the TLV.

   o  RESERVED: 8 bit field.  SHOULD be 0 on transmission and MUST be
      ignored on reception.

   o  Flags: 16 bits of flags defined as follow:

    0                   1
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |S|                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   where:

      *  S flag: if set then it means that the BGP speaker attaching the
         Prefix-SID Attribute to a prefix is capable of processing the
         IPv6 Segment Routing Header (SRH,
         [I-D.previdi-6man-segment-routing-header]) for the segment
         corresponding to the originated IPv6 prefix.  The use case
         leveraging the S flag is described in
         [I-D.filsfils-spring-segment-routing-msdc].

      The other bits of the flag field SHOULD be clear on transmission
      an MUST be ignored at reception.

4.3.  Originator SRGB TLV

   The Originator SRGB TLV is an optional TLV and has the following
   format:



















Patel, et al.           Expires January 21, 2016                [Page 7]


Internet-Draft                                                 July 2015


     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |     Type      |          Length               |    Flags      |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |     Flags     |
    +-+-+-+-+-+-+-+-+

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |         SRGB 1 (6 octets)                                     |
    |                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |         SRGB n (6 octets)                                     |
    |                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |                               |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   where:

   o  Type is 3.

   o  Length is the total length of the value portion of the TLV: 2 +
      multiple of 6.

   o  Flags: 16 bits of flags.  None are defined in this document.
      Flags SHOULD be clear on transmission an MUST be ignored at
      reception.

   o  SRGB: 3 octets of base followed by 3 octets of range.  Note that
      SRGB field MAY appear multiple times.

   The Originator SRGB TLV contains the SRGB of the router originating
   the prefix to which the BGP Prefix SID is attached and MUST be kept
   in the Prefix-SID Attribute unchanged during the propagation of the
   BGP update.

   The originator SRGB describes the SRGB of the node where the BGP
   Prefix Segment end.  It is used to build SRTE policies when different
   SRGB's are used in the fabric
   ([I-D.filsfils-spring-segment-routing-msdc]).

   The originator SRGB may only appear on Prefix-SID attribute attached
   to prefixes of SAFI 4 (labeled unicast, [RFC3107]).





Patel, et al.           Expires January 21, 2016                [Page 8]


Internet-Draft                                                 July 2015


5.  Receiving BGP-Prefix-SID Attribute

   A BGP speaker receiving a BGP Prefix-SID attribute from an EBGP
   neighbor residing outside the boundaries of the SR domain, SHOULD
   discard the attribute unless it is configured to accept the attribute
   from the EBGP neighbor.  A BGP speaker MAY log an error for further
   analysis when discarding an attribute.

5.1.  MPLS Dataplane: Labeled Unicast

   The Prefix-SID attribute MUST contain the Label-Index TLV and MAY
   contain the Originator SRGB.  A BGP Prefix-SID attribute received
   without a Label-Index TLV MUST be considered as "unacceptable" by the
   receiving speaker.

   A BGP speaker may be locally configured with an SRGB=[GB_S, GB_E].
   The preferred method for deriving the SRGB is a matter of local
   router configuration.

   Given a label index L_I, we call L = L_I + GB_S as the derived label.
   A BGP Prefix-SID attribute is called "unacceptable" for a speaker M
   if the derived label value L lies outside the SRGB configured on M.
   Otherwise the Label Index attribute is called "acceptable" to speaker
   M.

   The mechanisms through which a given label_index value is assigned to
   a given prefix are outside the scope of this document.  The label-
   index value associated with a prefix is locally configured at the BGP
   router originating the prefix.

   The Prefix-SID attribute MUST contain the Label-Index TLV and MAY
   contain the Originator SRGB TLV.  A BGP Prefix-SID attribute received
   without a Label-Index TLV MUST be considered as "unacceptable" by the
   receiving speaker.

   When a BGP speaker receives a path from a neighbor with an acceptable
   BGP Prefix-SID attribute, it SHOULD program the derived label as the
   local label for the prefix in its MPLS dataplane.  In case of any
   error, a BGP speaker MUST resort to the error handling rules
   specified in Section 7.  A BGP speaker MAY log an error for further
   analysis.

   When a BGP speaker receives a path from a neighbor with an
   unacceptable BGP Prefix-SID attribute, for the purpose of label
   allocation, it SHOULD treat the path as if it came without a Prefix-
   SID attribute.  A BGP speaker MAY choose to assign a local (also
   called dynamic) label (non-SRGB) for such a prefix.  A BGP speaker
   MAY log an error for further analysis.



Patel, et al.           Expires January 21, 2016                [Page 9]


Internet-Draft                                                 July 2015


   A BGP speaker receiving a prefix with a Prefix-SID attribute and a
   label NLRI field of implicit-null from a neighbor MUST adhere to
   standard behavior and program its MPLS dataplane to pop the top label
   when forwarding traffic to the prefix.  The label NLRI defines the
   outbound label that MUST be used by the receiving node.  The Label
   Index gives a hint to the receiving node on which local/incoming
   label the BGP speaker SHOULD use.

5.2.  IPv6 Dataplane

   When a SR IPv6 BGP speaker receives a IPv6 Unicast BGP Update with a
   prefix having the BGP Prefix SID attribute attached, it checks
   whether the IPv6 SID TLV is present and if the S-flag is set.  If the
   IPv6 SID TLV is not present or if the S-flag is not set, then the
   Prefix-SID attribute MUST be considered as "unacceptable" by the
   receiving speaker.

   The Originator SRGB MUST be ignored on reception.

   A BGP speaker receiving a BGP Prefix-SID attribute from an EBGP
   neighbor residing outside the boundaries of the SR domain, SHOULD
   discard the attribute unless it is configured to accept the attribute
   from the EBGP neighbor.  A BGP speaker MAY log an error for further
   analysis when discarding an attribute.

6.  Announcing BGP-Prefix-SID Attribute

   The BGP Prefix-SID attribute MAY be attached to labeled BGP prefixes
   (IPv4/IPv6) [RFC3107]or to IPv6 prefixes [RFC4760].  In order to
   prevent distribution of the BGP Prefix-SID attribute beyond its
   intended scope of applicability, attribute filtering MAY be deployed.

6.1.  MPLS Dataplane: Labeled Unicast

   A BGP speaker that originates a prefix attaches the Prefix-SID
   attribute when it advertises the prefix to its neighbors.  The value
   of the Label-Index in the Label-Index TLV is determined by
   configuration.

   A BGP speaker that originates a Prefix-SID attribute MAY optionally
   announce Originator SRGB TLV along with the mandatory Label-Index
   TLV.  The content of the Originator SRGB TLV is determined by the
   configuration.

   Since the Label-index value must be unique within an SR domain, by
   default an implementation SHOULD NOT advertise the BGP Prefix-SID
   attribute outside an Autonomous System unless it is explicitly
   configured to do so.



Patel, et al.           Expires January 21, 2016               [Page 10]


Internet-Draft                                                 July 2015


   A BGP speaker that advertises a path received from one of its
   neighbors SHOULD advertise the Prefix-SID received with the path
   without modification regardless of whether the Prefix-SID was
   acceptable.  If the path did not come with a Prefix-SID attribute,
   the speaker MAY attach a Prefix-SID to the path if configured to do
   so.  The content of the TLVs present in the Prefix-SID is determined
   by the configuration.

   In all cases, the label field of the NLRI ([RFC3107], [RFC4364]) MUST
   be set to the local/incoming label programmed in the MPLS dataplane
   for the given prefix.  If the prefix is associated with one of the
   BGP speakers interfaces, this label is the usual MPLS label (such as
   the implicit or explicit NULL label).

6.2.  IPv6 Dataplane

   A BGP speaker that originates a prefix attaches the Prefix-SID
   attribute when it advertises the prefix to its neighbors.  The IPv6
   SID TLV MUST be present and the S-flag MUST be set.

   A BGP speaker that advertises a path received from one of its
   neighbors SHOULD advertise the Prefix-SID received with the path
   without modification regardless of whether the Prefix-SID was
   acceptable.  If the path did not come with a Prefix-SID attribute,
   the speaker MAY attach a Prefix-SID to the path if configured to do
   so.  The IPv6-SID TLV MUST be present in the Prefix-SID and with the
   S-flag set.

7.  Error Handling of BGP-Prefix-SID Attribute

   When a BGP Speaker receives a BGP Update message containing a
   malformed BGP Prefix-SID attribute, it MUST ignore the received BGP
   Prefix-SID attributes and not pass it to other BGP peers.  This is
   equivalent to the -attribute discard- action specified in
   [I-D.ietf-idr-error-handling].  When discarding an attribute, a BGP
   speaker MAY log an error for further analysis.

   If the BGP Prefix-SID attribute appears more than once in an BGP
   Update message message, then, according to
   [I-D.ietf-idr-error-handling], all the occurrences of the attribute
   other than the first one SHALL be discarded and the BGP Update
   message shall continue to be processed.

   When a BGP speaker receives an unacceptable Prefix-SID attribute, it
   MAY log an error for further analysis.






Patel, et al.           Expires January 21, 2016               [Page 11]


Internet-Draft                                                 July 2015


8.  IANA Considerations

   This document defines a new BGP path attribute known as the BGP
   Prefix-SID attribute.  This document requests IANA to assign a new
   attribute code type (suggested value: 40) for BGP the Prefix-SID
   attribute from the BGP Path Attributes registry.

   This document defines two new TLVs for BGP Prefix-SID attribute.
   These TLVs need to be registered with IANA.  We request IANA to
   create a new registry for BGP Prefix-SID Attribute TLVs as follows:

   Under "Border Gateway Protocol (BGP) Parameters" registry, "BGP
   Prefix SID attribute Types" Reference: draft-keyupate-idr-bgp-prefix-
   side-05 Registration Procedure(s): Values 1-254 First Come, First
   Served, Value 0 and 255 reserved

   Value Type            Reference
   0     Reserved        draft-keyupate-idr-bgp-prefix-side-05
   1     Label-Index     draft-keyupate-idr-bgp-prefix-side-05
   2     IPv6 SID        draft-keyupate-idr-bgp-prefix-side-05
   3     Originator SRGB draft-keyupate-idr-bgp-prefix-side-05
   4-254 Unassigned
   255   Reserved        draft-keyupate-idr-bgp-prefix-side-05

9.  Security Considerations

   This document introduces no new security considerations above and
   beyond those already specified in [RFC4271] and [RFC3107].

10.  Acknowledgements

   The authors would like to thanks Satya Mohanty and Acee Lindem for
   their contribution to this document.

11.  Change Log

   Initial Version:  Sep 21 2014

12.  References

12.1.  Normative References

   [I-D.ietf-idr-error-handling]
              Chen, E., Scudder, J., Mohapatra, P., and K. Patel,
              "Revised Error Handling for BGP UPDATE Messages", draft-
              ietf-idr-error-handling-19 (work in progress), April 2015.





Patel, et al.           Expires January 21, 2016               [Page 12]


Internet-Draft                                                 July 2015


   [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>.

   [RFC3107]  Rekhter, Y. and E. Rosen, "Carrying Label Information in
              BGP-4", RFC 3107, DOI 10.17487/RFC3107, May 2001,
              <http://www.rfc-editor.org/info/rfc3107>.

   [RFC4271]  Rekhter, Y., Ed., Li, T., Ed., and S. Hares, Ed., "A
              Border Gateway Protocol 4 (BGP-4)", RFC 4271,
              DOI 10.17487/RFC4271, January 2006,
              <http://www.rfc-editor.org/info/rfc4271>.

   [RFC4364]  Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
              Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
              2006, <http://www.rfc-editor.org/info/rfc4364>.

12.2.  Informative References

   [I-D.filsfils-spring-segment-routing-central-epe]
              Filsfils, C., Previdi, S., Patel, K., Aries, E.,
              shaw@fb.com, s., Ginsburg, D., and D. Afanasiev, "Segment
              Routing Centralized Egress Peer Engineering", draft-
              filsfils-spring-segment-routing-central-epe-04 (work in
              progress), July 2015.

   [I-D.filsfils-spring-segment-routing-msdc]
              Filsfils, C., Previdi, S., Mitchell, J., Aries, E.,
              Lapukhov, P., Gaya, G., Afanasiev, D., Laberge, T.,
              Nkposong, E., Nanduri, M., Uttaro, J., and S. Ray, "BGP-
              Prefix Segment in large-scale data centers", draft-
              filsfils-spring-segment-routing-msdc-02 (work in
              progress), July 2015.

   [I-D.ietf-idr-bgpls-segment-routing-epe]
              Previdi, S., Filsfils, C., Ray, S., Patel, K., Dong, J.,
              and M. Chen, "Segment Routing Egress Peer Engineering BGP-
              LS Extensions", draft-ietf-idr-bgpls-segment-routing-
              epe-00 (work in progress), June 2015.

   [I-D.ietf-spring-segment-routing]
              Filsfils, C., Previdi, S., Decraene, B., Litkowski, S.,
              and R. Shakir, "Segment Routing Architecture", draft-ietf-
              spring-segment-routing-03 (work in progress), May 2015.






Patel, et al.           Expires January 21, 2016               [Page 13]


Internet-Draft                                                 July 2015


   [I-D.previdi-6man-segment-routing-header]
              Previdi, S., Filsfils, C., Field, B., and I. Leung, "IPv6
              Segment Routing Header (SRH)", draft-previdi-6man-segment-
              routing-header-06 (work in progress), May 2015.

   [RFC4760]  Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
              "Multiprotocol Extensions for BGP-4", RFC 4760,
              DOI 10.17487/RFC4760, January 2007,
              <http://www.rfc-editor.org/info/rfc4760>.

Authors' Addresses

   Keyur Patel
   Cisco Systems
   170 W. Tasman Drive
   San Jose, CA 95124  95134
   USA

   Email: keyupate@cisco.com


   Stefano Previdi
   Cisco Systems
   Via Del Serafico, 200
   Rome  00142
   Italy

   Email: sprevidi@cisco.com


   Clarence Filsfils
   Cisco Systems
   Brussels
   Belgium

   Email: cfilsfils@cisco.com


   Arjun Sreekantiah
   Cisco Systems
   170 W. Tasman Drive
   San Jose, CA 95124  95134
   USA

   Email: asreekan@cisco.com






Patel, et al.           Expires January 21, 2016               [Page 14]


Internet-Draft                                                 July 2015


   Saikat Ray
   Unaffiliated

   Email: raysaikat@gmail.com


   Hannes Gredler
   Juniper Networks

   Email: hannes@juniper.net









































Patel, et al.           Expires January 21, 2016               [Page 15]

Html markup produced by rfcmarkup 1.124, available from https://tools.ietf.org/tools/rfcmarkup/