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Versions: 00 01 02 03 04 05 06 07 08 draft-ietf-pce-vn-association

PCE Working Group                                                 Y. Lee
Internet-Draft                                                  D. Dhody
Intended Status: Standards track                                X. Zhang
Expires: May 1, 2017                                 Huawei Technologies
                                                           D. Ceccarelli
                                                                Ericsson
                                                        October 28, 2016


  PCEP Extensions for Establishing Relationships Between Sets of LSPs
                       and Virtual Networks
                 draft-leedhody-pce-vn-association-01


Abstract

   This document describes how to extend Path Computation Element (PCE)
   Communication Protocol (PCEP) association mechanism introduced by the
   PCEP Association Group specification, to further associate sets of
   LSPs with a higher-level structure such as a virtual network (VN)
   requested by clients or applications. This extended association
   mechanism can be used to facilitate virtual network control using PCE
   architecture.



Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   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."











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   described in the Simplified BSD License.

Table of Contents


   1. Introduction...................................................2
      1.1. Requirements Language.....................................3
   2. Terminology....................................................4
   3. Operation Overview.............................................4
   4. Extensions to PCEP.............................................4
   5. Applicability to H-PCE architecture............................6
   6. Security Considerations........................................7
   7. IANA Considerations............................................7
      7.1. Association Object Type Indicator.........................7
      7.2. PCEP TLV Type Indicator...................................8
      7.3. PCEP Error................................................8
   8. References.....................................................8
      8.1. Normative References......................................8
      8.2. Informative References....................................9
   Author's Addresses................................................9

1. Introduction

   The Path Computation Element communication Protocol (PCEP) provides
   mechanisms for Path Computation Elements (PCEs) to perform path
   computations in response to Path Computation Clients' (PCCs)
   requests.



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   [I-D.ietf-pce-stateful-pce-app] describes general considerations for
   a stateful PCE deployment and examines its applicability and
   benefits, as well as its challenges and limitations through a number
   of use cases.  [I-D.ietf-pce-stateful-pce] describes a set of
   extensions to PCEP to provide stateful control.  A stateful PCE has
   access to not only the information carried by the network's Interior
   Gateway Protocol (IGP), but also the set of active paths and their
   reserved resources for its computations.  The additional state allows
   the PCE to compute constrained paths while considering individual
   LSPs and their interactions.

   [I-D.ietf-pce-pce-initiated-lsp] describes the setup, maintenance and
   teardown of PCE-initiated LSPs under the stateful PCE model.

   [I-D.ietf-pce-association-group] introduces a generic mechanism to
   create a grouping of LSPs. This grouping can then be used to define
   association between sets of LSPs or between a set of LSPs and a set
   of attributes.

   [ACTN-REQ] describes various Virtual Network (VN) operations
   initiated by a customer/application. In this context, there is a need
   for associating a set of LSPs with a VN "construct" to facilitate VN
   operations in PCE architecture. This association allows the PCEs to
   identify which LSPs belong to a certain VN. The PCE could then use
   this association to optimize all LSPs belonging to the VN together.
   The PCE could further take VN specific actions on the LSPs such as
   relaxation of constraints, policy actions, setting default behavior
   etc.

   [I-D.dhody-pce-applicability-actn] examines the PCE and ACTN
   architecture and describes how the PCE architecture is applicable to
   ACTN. [RFC6805] and [I-D.dhodylee-pce-stateful-hpce] describes a
   hierarchy of stateful PCEs with Parent PCE coordinating multi-domain
   path computation function between Child PCE(s) and thus making it the
   base for PCE applicability for ACTN.

   This document specifies a PCEP extension to associate a set of LSPs
   based on Virtual Network (or customer).

1.1. 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 [RFC2119].







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2. Terminology

   The terminology is as per [RFC4655], [RFC5440], [RFC6805], and [I-
   D.ietf-pce-stateful-pce].

3. Operation Overview

   As per [I-D.ietf-pce-association-group], LSPs are associated with
   other LSPs with which they interact by adding them to a common
   association group. In this draft, this grouping is used to define
   associations between a set of LSPs and a virtual network.

   One new optional Association Object-type is defined based on the
   generic Association object -

      o  VN Association Group (VNAG)

   Thus this document define one new association type called "VN
   Association Type" of value TBD1.  The scope and handling of VNAG
   identifier is similar to the generic association identifier defined
   in [I-D.ietf-pce-association-group].



4. Extensions to PCEP

    [I-D.ietf-pce-association-group] introduces the ASSOCIATION object,
   the format of VNAG is as follows:



















    0                   1                   2                   3



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    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Reserved                      | Flags                       |R|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        Association type=TBD1  |          Association ID       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     IPv4 Association Source                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   //                         Optional TLVs                       //
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         Reserved              |            Flags            |R|
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Association type=TBD1    |      Association ID           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                    IPv6 Association Source                    |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   //                   Optional TLVs                             //
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

             Figure 1: The VNAG Object formats

   Please refer to [I-D.ietf-pce-association-group] for the definition
   of each field in Figure 1. This document defines one mandatory TLV.

   o VIRTUAL-NETWORK-TLV: Used to communicate the VN Identifier.



   The format of VIRTUAL-NETWORK-TLV is as follows.














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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

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           Type=TBD2           |       Length (variable)       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                   Virtual Network Name                      //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


              Figure 2: The VIRTUAL-NETWORK-TLV formats

   Type: TBD2 (to be allocated by IANA)

   Length: Variable Length

   Virtual Network Name(variable): symbolic name for the VN.

   The VIRTUAL-NETWORK-TLV MUST be included in VNAG object.If a PCEP
   speaker receives the VNAG object without the VIRTUAL-NETWORK-TLV, it
   MUST send a PCErr message with Error-Type= 6 (mandatory object
   missing) and Error-Value=TBD3 (VIRTUAL-NETWORK-TLV missing) and close
   the session.


5. Applicability to H-PCE architecture

   The ability to compute shortest constrained TE LSPs in Multiprotocol
   Label Switching (MPLS) and Generalized MPLS (GMPLS) networks across
   multiple domains has been identified as a key motivation for PCE
   development.  [RFC6805] describes a Hierarchical PCE (H-PCE)
   architecture which can be used for computing end-to-end paths for
   inter-domain MPLS Traffic Engineering (TE) and GMPLS Label Switched
   Paths (LSPs).  Within the hierarchical PCE architecture, the parent
   PCE is used to compute a multi-domain path based on the domain
   connectivity information.  A child PCE may be responsible for a
   single domain or multiple domains, it is used to compute the intra-
   domain path based on its domain topology information.

   [I-D.ietf-dhodylee-stateful-hpce] introduces general considerations
   for stateful PCE(s) in hierarchical PCE architecture.  In particular,
   the behavior changes and additions to the existing stateful PCE
   mechanisms in the context of a H-PCE architecture.

   In Stateful H-PCE architecture, the Parent PCE receives a virtual



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   network creation request by its client over its Northbound API. This
   VN is uniquely identified by an Association ID in VNAG as well as the
   VIRTUAL-NETWORK name. This VN may comprise multiple LSPs in the
   network in a single domain or across multiple domains.

   As the Parent PCE computes the optimum E2E paths for each tunnel in
   VN, it MUST associate each LSP with the VN to which it belongs.
   Parent PCE sends a PCInitiate Message with this association
   information in the VNAG Object (See Section 4 for details). This in
   effect binds an LSP that is to be instantiated at the child PCE with
   the VN.

   Whenever changes occur with the instantiated LSP in a domain network,
   the domain child PCE reports the changes using a PCRpt Message in
   which the VNAG Object indicates the relationship between the LSP and
   the VN.

   Whenever an update occurs with VNs in the Parent PCE (via the
   client's request), the parent PCE sends an PCUpd Message to inform
   each affected child PCE of this change.

   The Child PCE could then use this association to optimize all LSPs
   belonging to the same VN association together. The Child PCE could
   further take VN specific actions on the LSPs such as relaxation of
   constraints, policy actions, setting default behavior etc. The parent
   PCE could also maintain all E2E LSP or per-domain path segments under
   a single VN association.



6. Security Considerations

   TDB

7. IANA Considerations

7.1. Association Object Type Indicator

   This document defines the following new association type originally
   defined in [I-D.ietf-pce-association-group].



      Value     Name                        Reference

      TBD1      VN Association Type         [This I.D.]





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7.2. PCEP TLV Type Indicator

   This document defines the following new PCEP TLV; IANA is requested
   to make the following allocations from this registry at
   <http://www.iana.org/assignments/pcep/>; see PCEP TLV Type
   Indicators.



      Value     Name                        Reference

      TBD2      VIRTUAL-NETWORK-TLV         [This I.D.]

7.3. PCEP Error

   IANA is requested to make the following allocations from this
   registry at <http://www.iana.org/assignments/pcep/>; see PCEP-ERROR
   Object Error Types and Values.

   This document defines new Error-Type and Error-Value for the
   following new error conditions:



       Error-Type  Meaning

          6        Mandatory Object missing

                    Error-value=TBD3: VIRTUAL-NETWORK TLV missing

8. References

8.1. 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.

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

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

   [I-D.ietf-pce-pce-initiated-lsp] E. Crabbe, et. al., "PCEP Extensions
             for PCE-initiated LSP Setup in a Stateful PCE Model",



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             draft-ietf-pce-pce-initiated-lsp, work in progress.

   [I-D.ietf-pce-association-group] I, Minei, Ed., "PCEP Extensions for
             Establishing Relationships Between Sets of LSPs", draft-
             ietf-pce-association-group, work in progress.

8.2. Informative References

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

   [RFC6805] A. Farrel and D. King, "The Application of the Path
             Computation Element Architecture to the Determination of a
             Sequence of Domains in MPLS and GMPLS", RFC 6805, November
             2012.

   [I-D.ietf-pce-stateful-pce-app] Zhang, X., ED, and Minei, I., ED,
             "Applicability of a Stateful Path Computation Element
             (PCE)", draft-ietf-pce-stateful-pce-app, work-in-progress.

   [I-D.dhody-pce-applicability-actn] Dhody D., Lee Y., and D.
             Ceccarelli, "Applicability of Path Computation Element
             (PCE) for Abstraction and Control of TE Networks (ACTN)",
             draft-dhody-pce-applicability-actn, work-in-progress.

   [I-D.ietf-dhodylee-stateful-hpce] Dhody, D. and Lee, Y.,
             "Hierarchical Stateful Path Computation Element (PCE)",
             draft-dhodylee-pce-stateful-hpce, work in progress.

   [ACTN-REQ] Y. Lee, D. Dhody, S. Belotti, K. Pithewan, and D.
             Ceccarelli, "Requirements for Abstraction and Control of TE
             Networks", draft-ietf-teas-actn-requirements, work in
             progress.

 Author's Addresses


   Young Lee (Editor)
   Huawei Technologies
   5340 Legacy Drive, Building 3
   Plano, TX 75023,
   USA

   Email: leeyoung@huawei.com







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   Dhruv Dhody (Editor)
   Huawei Technologies
   Divyashree Technopark, Whitefield
   Bangalore, Karnataka  560066
   India

   Email: dhruv.ietf@gmail.com

   Xian Zhang
   Huawei Technologies
   China

   Email: zhang.xian@huawei.com

   Daniele Ceccarelli
   Ericsson
   Torshamnsgatan,48
   Stockholm,
   Sweden

   Email: daniele.ceccarelli@ericsson.com






























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