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Versions: 00 01 02 03 04 draft-ietf-idr-te-lsp-distribution

Network Working Group                                            J. Dong
Internet-Draft                                                   M. Chen
Intended status: Standards Track                     Huawei Technologies
Expires: April 24, 2014                                       H. Gredler
                                                  Juniper Networks, Inc.
                                                              S. Previdi
                                                     Cisco Systems, Inc.
                                                        October 21, 2013


   Distribution of MPLS Traffic Engineering (TE) LSP State using BGP
                 draft-dong-idr-te-lsp-distribution-04

Abstract

   This document describes a mechanism to collect the Traffic
   Engineering (TE) LSP information using BGP.  Such information can be
   used by external components for path reoptimization, service
   placement and network visualization.

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].

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 April 24, 2014.









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Copyright Notice

   Copyright (c) 2013 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
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   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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Carrying LSP State Information in BGP . . . . . . . . . . . .   4
     2.1.  LSP Identifier Information  . . . . . . . . . . . . . . .   4
     2.2.  LSP State Information . . . . . . . . . . . . . . . . . .   5
   3.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   5.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     5.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     5.2.  Informative References  . . . . . . . . . . . . . . . . .   7
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   In some network environments, the states of established Multi-
   Protocol Label Switching (MPLS) Traffic Engineering (TE) Label
   Switched Paths (LSPs) in the network are required by some components
   external to the network domain.  Usually this information is directly
   maintained by the ingress Label Edge Routers (LERs) of the MPLS TE
   LSPs.

   One example of using the LSP information is stateful Path Computation
   Element (PCE) [I-D.ietf-pce-stateful-pce], which could provide
   benefits in path reoptimization . While some extensions are proposed
   in Path Computation Element Communication Protocol (PCEP) for the
   Path Computation Clients (PCCs) to report the LSP states to the PCE,
   this mechanism may not be applicable in a management-based PCE
   architecture as specified in section 5.5 of [RFC4655].  As
   illustrated in the figure below, the PCC is not an LSR in the routing
   domain, thus the head-end nodes of the TE-LSP may not implement the
   PCEP protocol.  In this case some general mechanism to collect the
   TE-LSP states from the ingress LERs is needed.  This document



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   proposes an LSP state collection mechanism complementary to the
   mechanism defined in [I-D.ietf-pce-stateful-pce].

                                    -----------
                                   |   -----   |
               Service             |  | TED |<-+----------->
               Request             |   -----   |  TED synchronization
                  |                |     |     |  mechanism (for example,
                  v                |     |     |  routing protocol)
            ------------- Request/ |     v     |
           |             | Response|   -----   |
           |     NMS     |<--------+> | PCE |  |
           |             |         |   -----   |
            -------------           -----------
          Service |
          Request |
                  v
             ----------  Signaling   ----------
            | Head-End | Protocol   | Adjacent |
            |  Node    |<---------->|   Node   |
             ----------              ----------

                  Figure 1.  Management-Based PCE Usage


   In networks with composite PCE nodes as specified in section 5.1 of
   [RFC4655], the PCE is implemented on several routers in the network,
   and the PCCs in the network can use the mechanism described in
   [I-D.ietf-pce-stateful-pce] to report the LSP information to the PCE
   nodes.  An external component may further need to collect the LSP
   information from all the PCEs in the network to get a global view of
   the LSP states in the network.

   In some networks, a centralized controller is used for service
   placement.  Obtaining the TE LSP state information is quite important
   for making appropriate service placement decisions with the purpose
   of both meeting the application's requirements and utilizing the
   network resource efficiently.

   The Network Management System (NMS) may need to provide global
   visibility of the TE LSPs in the network as part of the network
   visualization function.

   BGP has been extended to distribute link-state and traffic
   engineering information and share with some external components
   [I-D.ietf-idr-ls-distribution].  Using the same protocol to collect
   other network layer information would be desired by the external
   components, which avoids introducing multiple protocols for network



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   information collection.  This document describes a mechanism to
   distribute the TE LSP information to external components using BGP.

2.  Carrying LSP State Information in BGP

2.1.  LSP Identifier Information

   The TE LSP Identifier information is advertised in BGP UPDATE
   messages using the MP_REACH_NLRI and MP_UNREACH_NLRI attributes
   [RFC4760].  The "Link State NLRI" defined in
   [I-D.ietf-idr-ls-distribution] is extended to carry the TE LSP
   Identifier information.  BGP speakers that wish to exchange TE LSP
   information MUST use the BGP Multiprotocol Extensions Capability Code
   (1) to advertise the corresponding (AFI, SAFI) pair, as specified in
   [RFC4760].

   The format of "Link State NLRI" is defined in
   [I-D.ietf-idr-ls-distribution].  Two new "NLRI Type" are defined for
   TE LSP Identifier Information as following:

   o  NLRI Type = 5: IPv4 TE LSP NLRI

   o  NLRI-Type = 6: IPv6 TE LSP NLRI

   The IPv4 TE LSP NLRI (NLRI Type = 5) is shown in the following
   figure:

    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
   +-+-+-+-+-+-+-+-+
   |  Protocol-ID  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           Identifier                          |
   |                            (64 bits)                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                   IPv4 Tunnel Sender Address                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             Tunnel ID         |             LSP ID            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  IPv4 Tunnel End-point Address                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     Figure 2. IPv4 TE LSP NLRI


   The IPv6 TE LSP NLRI (NLRI Type = 6) is shown in the following
   figure:





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    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
   +-+-+-+-+-+-+-+-+
   |  Protocol-ID  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           Identifier                          |
   |                            (64 bits)                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   +                                                               +
   |                  IPv6 Tunnel Sender Address                   |
   +                          (16 octets)                          +
   |                                                               |
   +                                                               +
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          Tunnel ID            |             LSP ID            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   +                                                               +
   |                 IPv6 Tunnel End-point Address                 |
   +                          (16 octets)                          +
   |                                                               |
   +                                                               +
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                     Figure 3. IPv6 TE LSP NLRI


   For IPv4 TE LSP NLRI and IPv6 TE LSP NLRI, the Protocol-ID field is
   set to 6, which indicates that the NLRI information has been sourced
   by RSVP-TE.

   The Identifier field is used to discriminate between instances with
   different LSP technology - e.g. one identifier can identify the
   instance for packet path, and another one is to identify the instance
   of optical path.

   The other fields in the IPv4 TE LSP NLRI and IPv6 TE LSP NLRI are the
   same as specified in [RFC3209].

2.2.  LSP State Information

   The LSP State TLV is used to describe the characteristics of the TE
   LSPs, which is carried in the optional non-transitive BGP Attribute
   "LINK_STATE Attribute" defined in [I-D.ietf-idr-ls-distribution].





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   The "Value" field of the LSP State TLV corresponds to the format and
   semantics of a set of objects defined in [RFC3209], [RFC3473] and
   [RFC5440] for TE LSPs.  Rather than replicating all RSVP-TE related
   objects in this document the semantics and encodings of existing
   RSVP-TE objects are re-used.  Hence all RSVP-TE LSP objects are
   regarded as sub-TLVs.  The LSP State TLV SHOULD only be used with
   IPv4/IPv6 TE LSP NLRI.

    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            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   ~                   TE LSP Objects (variable)                       ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                   Figure 4. LSP State TLV


   Currently the TE LSP Objects that can be carried in the LSP State TLV
   include:

   o  LSP Attributes (LSPA) Object [RFC5440]

   o  Explicit Route Object (ERO) [RFC3209]

   o  Record Route Object (RRO) [RFC3209]

   o  BANDWIDTH Object [RFC5440]

   o  METRIC Object [RFC5440]

   o  Protection Object [RFC3473]

   o  Admin_Status Object [RFC3473]

   Other TE LSP objects may also be carried in LSP state TLV, which is
   for further study.

3.  IANA Considerations

   IANA needs to assign one new TLV type for "LSP State TLV" from the
   TLV registry of Link_State Attribute.

   IANA needs to assign one Protocol-ID for 'RSVP-TE' from the BGP-TE/LS
   registry of Protocol-IDs.




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4.  Security Considerations

   Procedures and protocol extensions defined in this document do not
   affect the BGP security model.  See [RFC6952] for details.

5.  References

5.1.  Normative References

   [I-D.ietf-idr-ls-distribution]
              Gredler, H., Medved, J., Previdi, S., Farrel, A., and S.
              Ray, "North-Bound Distribution of Link-State and TE
              Information using BGP", draft-ietf-idr-ls-distribution-03
              (work in progress), May 2013.

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

   [RFC3209]  Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
              and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
              Tunnels", RFC 3209, December 2001.

   [RFC3473]  Berger, L., "Generalized Multi-Protocol Label Switching
              (GMPLS) Signaling Resource ReserVation Protocol-Traffic
              Engineering (RSVP-TE) Extensions", RFC 3473, January 2003.

   [RFC4760]  Bates, T., Chandra, R., Katz, D., and Y. Rekhter,
              "Multiprotocol Extensions for BGP-4", RFC 4760, January
              2007.

   [RFC5440]  Vasseur, JP. and JL. Le Roux, "Path Computation Element
              (PCE) Communication Protocol (PCEP)", RFC 5440, March
              2009.

5.2.  Informative References

   [I-D.ietf-pce-stateful-pce]
              Crabbe, E., Medved, J., Minei, I., and R. Varga, "PCEP
              Extensions for Stateful PCE", draft-ietf-pce-stateful-
              pce-07 (work in progress), October 2013.

   [RFC4655]  Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
              Element (PCE)-Based Architecture", RFC 4655, August 2006.

   [RFC6952]  Jethanandani, M., Patel, K., and L. Zheng, "Analysis of
              BGP, LDP, PCEP, and MSDP Issues According to the Keying
              and Authentication for Routing Protocols (KARP) Design
              Guide", RFC 6952, May 2013.



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Authors' Addresses

   Jie Dong
   Huawei Technologies
   Huawei Building, No. 156 Beiqing Rd.
   Beijing  100095
   China

   Email: jie.dong@huawei.com


   Mach(Guoyi) Chen
   Huawei Technologies
   Huawei Building, No. 156 Beiqing Rd.
   Beijing  100095
   China

   Email: mach.chen@huawei.com


   Hannes Gredler
   Juniper Networks, Inc.
   1194 N. Mathilda Ave.
   Sunnyvale, CA  94089
   US

   Email: hannes@juniper.net


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

   Email: sprevidi@cisco.com















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