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Versions: (draft-otani-pce-gmpls-aps-req) 00 01 02 03 04 05 06 07 08 09 RFC 7025

INTERNET-DRAFT                                           Tomohiro Otani
Intended status: Informational                            Kenichi Ogaki
Expires:March 2009                                        KDDI R&D Labs
                                                         Diego Caviglia
                                                               Ericsson
                                                          Sept 17, 2008


                Requirements for GMPLS applications of PCE

               Document: draft-ietf-pce-gmpls-aps-req-00.txt



Status of this Memo

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Abstract

   The initial effort of PCE WG is specifically focused on MPLS (Multi-
   protocol label switching). As a next step, this draft describes
   functional requirements for GMPLS (Generalized MPLS) application of
   PCE (Path computation element).


Table of Contents

   Status of this Memo................................................ 1
   Abstract........................................................... 1
   1. Introduction.................................................... 3
   2. Conventions used in this document............................... 3
   3. GMPLS applications of PCE....................................... 3
   4. Requirement for GMPLS application of PCE........................ 4
   5. Security consideration.......................................... 5

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   6. IANA Considerations............................................. 5
   7. Acknowledgement................................................. 5
   8. Intellectual property considerations............................ 5
   9. Informative references.......................................... 6
   Author's Addresses................................................. 7
   Document expiration................................................ 7
   Copyright statement................................................ 7

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1. Introduction

   The initial effort of PCE WG is focused on solving the path
   computation problem over domains in MPLS networks. As the same case
   with MPLS, service providers (SPs) have also come up with
   requirements for path computation in GMPLS networks such as photonics,
   TDM-based or Ethernet-based networks as well.

   [PCE-ARCH] and [PCECP-REQ] discuss the framework and requirements for
   PCE on both packet MPLS networks and (non-packet switch capable)
   GMPLS networks. This document complements these documents by
   providing some consideration of GMPLS applications in the inter-
   domain networking environment and indicating a set of requirements
   for the extended definition of series of PCE related protocols.

   Constraint based shortest path first (CSPF) computation within a
   domain or over domains for signaling GMPLS Label Switched Paths
   (LSPs) is more stringent than that of MPLS LSPs [MPLS-AS], because
   the additional constraints, e.g., interface switching capability,
   link encoding, link protection capability and so forth need to be
   considered to establish GMPLS LSPs [CSPF]. GMPLS signaling protocol
   [RFC3471, RFC3473] is designed taking into account bi-directionality,
   switching type, encoding type, SRLG, and protection attributes of the
   TE links spanned by the path, as well as LSP encoding type and
   switching type for the end points, appropriately.

   This document provides the investigated results of GMPLS applications
   of PCE especially for the support of GMPLS inter-domain path
   computation. This document also outlines GMPLS inter-domain
   architecture, and provides requirements for GMPLS applications of PCE
   in the GMPLS inter-domain environment.


2. Conventions used in this document

   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].


3. GMPLS applications of PCE

   3.1 GMPLS network model

   Figure 1 depicts a typical network, consisting of several GMPLS
   domains, assumed in this document. D1, D2, D3 and D4 have multiple
   GMPLS inter-domain connections, and D5 has only one GMPLS inter-
   domain connection. These domains follow the definition in [RFC4726].


                    +---------+
          +---------|GMPLS  D2|----------+
          |         +----+----+          |
     +----+----+         |          +----+----+   +---------+

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     |GMPLS  D1|         |          |GMPLS  D4|---|GMPLS  D5|
     +----+----+         |          +----+----+   +---------+
          |         +----+----+          |
          +---------|GMPLS  D3|----------+
                    +---------+

                Figure 1: GMPLS Inter-domain network model.

   Each domain is configured using various switching and link
   technologies defined in [Arch] and an end-to-end route needs to
   respect TE link attributes like multiplexing type, encoding type,
   etc., making the problem a bit different from the case of classical
   (packet) MPLS. In order to route from one GMPLS domain to another
   GMPLS domain appropriately, each domain manages traffic engineering
   database (TED) by PCE, and exchanges or provides route information of
   paths, while concealing its internal topology information.

   3.2 Path computation in GMPLS network

   [CSPF] describes consideration of GMPLS TE attributes during path
   computation.


             Ingress             Transit             Egress
   +-----+   link1-2   +-----+   link2-3   +-----+   link3-4   +-----+
   |Node1|------------>|Node2|------------>|Node3|------------>|Node4|
   |     |<------------|     |<------------|     |<------------|     |
   +-----+   link2-1   +-----+   link3-2   +-----+   link4-3   +-----+

               Figure 2: Path computation in GMPLS networks.

   For the simplicity in consideration, the below basic assumptions are
   made when the LSP is created.

       (1) Switching capabilities of outgoing links from the ingress
           and egress nodes (link1-2 and link4-3 in Figure .) must be
           consistent with each other.
       (2) SC of all transit links including incoming links to the
           ingress and egress nodes (link2-1 and link3-4) should be
           consistent with switching type of a LSP to be created.
       (3) Encoding-types of all transit links should be consistent
           with encoding type of a LSP to be created.

   [CSPF] indicates the possible table of switching capability, encoding
   type and bandwidth at the ingress link, transiting links and the
   egress link which need to be satisfied with the created LSP.


4. Requirement for GMPLS application of PCE

   In this section, we describe requirements for GMPLS applications of
   PCE in order to establish GMPLS LSP over domains.

   4.1 PCE requirements

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   As for path computation in GMPLS networks as discussed in section 3,
   the PCE needs to consider the GMPLS TE attributes appropriately
   according to tables in [CSPF] once a PCC or another PCE requests a
   path computation. Indeed, the path calculation request message from
   the PCC or the PCE needs to contain the information specifying
   appropriate attributes. Additional attributes to those already
   defined in [PCECP] are as follows.

   (1) Switching capability: PSC1-4, L2SC, TDM, lambda, LSC, FSC
   (2) Encoding type: as defined in [RFC4202], [RFC4203], e.g., Ethernet,
   SONET/SDH, Lambda, etc.
   (3) e2e Path protection type: as defined in [RFC4872], e.g., 1+1
   protection, 1:1 protection, (pre-planned) rerouting, etc.
   (4) Administrative group: as defined in [RFC3630]
   (5) Link Protection type: as defined in [RFC4203]

   4.2 PCC requirements

   As described above, a PCC needs to support to initiate path
   computation request specifying abovementioned attributes. Afterwards,
   GMPLS signaling will be invoked according to the responded messages
   from the PCE.

   4.3 GMPLS PCE Management

   PCE related Management Information Bases need to consider extensions
   to be satisfied with requirements for GMPLS applications. For
   extensions, [GMPLS-TEMIB] are defined to manage TE database and may
   be referred to accommodate GMPLS TE attributes in the PCE.


5. Security consideration

   PCE extensions to support GMPLS should be considered under the same
   security as current work. This extension will not change the
   underlying security issues.


6. IANA Considerations

   This document has no actions for IANA.


7. Acknowledgement

   The author would like to express the thanks to Shuichi Okamoto for
   his comments.


8. Intellectual property considerations

   The IETF takes no position regarding the validity or scope of any
   Intellectual Property Rights or other rights that might be claimed to

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   pertain to the implementation or use of the technology described in
   this document or the extent to which any license under such rights
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   made any independent effort to identify any such rights.  Information
   on the procedures with respect to rights in RFC documents can be
   found in BCP 78 and BCP 79.

   Copies of IPR disclosures made to the IETF Secretariat and any
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   The IETF invites any interested party to bring to its attention any
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   this standard. Please address the information to the IETF at ietf-
   ipr@ietf.org.


9. Informative references
  [RFC2119]      Bradner, S., "Key words for use in RFCs to Indicate
                  Requirement Levels", BCP 14, RFC 2119, March 1997.
  [PCE-ARCH]     A. Farrel, et al, "A Path Computation Element (PCE)-
                  Based Architecture", RFC4655, Aug., 2006.
  [PCECP-REQ]    J. Ash, et al, "Path computation element (PCE)
                  communication protocol generic requirements", RFC4657,
                  Sept., 2007.
  [MPLS-AS]      R. Zhan, et al, "MPLS Inter-Autonomous System (AS)
                  Traffic Engineering (TE) Requirements", RFC4216,
                  November 2005.
  [CSPF]         T. Otani, et al, "Considering Generalized
                  Multiprotocol Label Switching Traffic Engineering
                  Attributes During Path Computation", draft-otani-
                  ccamp-gmpls-cspf-constraints-07.txt, Feb., 2008.
  [RFC3471]      Berger, L., "Generalized Multi-Protocol Label
                  Switching (MPLS) Signaling Functional Description",
                  RFC 3471, January 2003.
  [RFC3473]      Berger, L., "Generalized Multi-Protocol Label
                  Switching (MPLS) Signaling - Resource ReserVation
                  Protocol Traffic Engineering (RSVP-TE) Extensions",
                  RFC 3473, January 2003.
  [RFC4726]      A. Farrel, et al, "A framework for inter-domain MPLS
                  traffic engineering", RFC4726, November 2006.
  [Arch]         E. Mannie, et al, "Generalized Multi-Protocol Label
                  Switching Architecture", RFC3945, October, 2004.
  [PCECP]        J.P. Vasseur, et al, "Path Computation Element (PCE)
                  Communication Protocol (PCEP)", draft-ietf-pce-pcep-
                  15.txt, March 2008.
  [RFC4202]      K. Kompella, and Y. Rekhter, "Routing Extensions in
                  Support of Generalized Multi-Protocol Label
                  Switching", RFC4202, Oct. 2005.

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  [RFC4203]      K. Kompella, and Y. Rekhter, "OSPF Extensions in
                  Support of Generalized Multi-Protocol Label
                  Switching", RFC4203, Oct. 2005.
  [RFC4872]      J.P. Lang, Ed., "RSVP-TE Extensions in Support of
                  End-to-End Generalized Multi-Protocol Label Switching
                  (GMPLS) Recovery", RFC4872, May 2007.
  [GMPLS-TEMIB]   T. Nadeau and A. Farrel, Ed., "Generalized
                  Multiprotocol Label Switching (GMPLS) Traffic
                  Engineering Management Information Base", RFC4802,
                  Feb. 2007.
  [RFC3630]      D. Katz et al, "Traffic Engineering (TE) Extensions
                  to OSPF Version 2", RFC3630, September 2003.


Author's Addresses

   Tomohiro Otani
   KDDI R&D Laboratories, Inc.
   2-1-15 Ohara Kamifukuoka Saitama, 356-8502. Japan
   Phone:  +81-49-278-7357
   Email:  otani@kddilabs.jp

   Kenichi Ogaki
   KDDI R&D Laboratories, Inc.
   2-1-15 Ohara Kamifukuoka Saitama, 356-8502. Japan
   Phone:  +81-49-278-7897
   Email:  ogaki@kddilabs.jp

   Diego Caviglia
   Ericsson
   16153 Genova Cornigliano, ITALY
   Phone: +390106003736
   Email: diego.caviglia@ericsson.com


Document expiration

   This document will be expired in March 31, 2009, unless it is updated.


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   OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF

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   THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
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