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Versions: 00 01 02 03 draft-ietf-pce-remote-initiated-gmpls-lsp

     PCE Working Group                                         Zafar Ali
     Internet Draft                                       Siva Sivabalan
     Intended status: Standard Track                   Clarence Filsfils
     Expires: August 13, 2014                              Cisco Systems
                                                            Robert Varga
                                                   Pantheon Technologies
                                                            Victor Lopez
                                                  Oscar Gonzalez de Dios
                                                          Telefonica I+D
                                                              Xian Zhang
                                                                  Huawei
                                                       February 14, 2014
     
     
             Path Computation Element Communication Protocol (PCEP)
                Extensions for remote-initiated GMPLS LSP Setup
                draft-ali-pce-remote-initiated-gmpls-lsp-03.txt
     
     
     Status of this Memo
     
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     This Internet-Draft will expire on August 13, 2014.
     
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     Abstract
     
     Draft [I-D. draft-crabbe-pce-pce-initiated-lsp] specifies
     procedures that can be used for creation and deletion of PCE-
     initiated LSPs in the active stateful PCE model. However, this
     specification focuses on MPLS networks, and does not cover remote
     instantiation of paths in GMPLS-controlled networks. This document
     complements [I-D. draft-crabbe-pce-pce-initiated-lsp] by addressing
     the requirements for remote-initiated GMPLS LSPs.
     
     
     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].
     
     Table of Contents
     
        1. Introduction .............................................3
        2. Requirements for Remote-Initiated GMPLS LSPs .............3
        3. PCEP Extensions for Remote-Initiated GMPLS LSPs ..........4
          3.1. Generalized Endpoint in LSP Initiate Message .........4
          3.2. GENERALIZED-BANDWIDTH object in LSP Initiate Message .5
          3.3. Protection Attributes in LSP Initiate Message ........5
          3.4. ERO in LSP Initiate Object ...........................5
              3.4.1. ERO with explicit label control ................5
              3.4.2. ERO with Path Keys .............................6
              3.4.3. Switch Layer Object ............................6
          3.5. LSP delegation and cleanup ...........................7
        4. Security Considerations ..................................7
        5. IANA Considerations ......................................7
          5.1. PCEP-Error Object ....................................7
        6. Acknowledgments ..........................................7
        7. References ...............................................7
          7.1. Normative References .................................7
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          7.2. Informative References ...............................8
     
     1. Introduction
     
        The Path Computation Element communication Protocol (PCEP)
        provides mechanisms for Path Computation Elements (PCEs) to
        perform route computations in response to Path Computation
        Clients (PCCs) requests. PCEP Extensions for PCE-initiated LSP
        Setup in a Stateful PCE Model draft [I-D. draft-ietf-pce-
        stateful-pce] describes a set of extensions to PCEP to enable
        active control of MPLS-TE and GMPLS network.
     
        [I-D. draft-crabbe-pce-pce-initiated-lsp] describes the setup
        and teardown of PCE-initiated LSPs under the active stateful PCE
        model, without the need for local configuration on the PCC. This
        enables realization of a dynamic network that is centrally
        controlled and deployed. However, this specification is focused
        on MPLS networks, and does not cover the GMPLS networks (e.g.,
        WSON, OTN, SONET/ SDH, etc. technologies). This document
        complements [I-D. draft-crabbe-pce-pce-initiated-lsp] by
        addressing the requirements for remote-initiated GMPLS LSPs.
        These requirements are covered in Section 2 of this draft. The
        PCEP extensions for remote initiated GMPLS LSPs are specified in
        Section 3.
     
     2. Requirements for Remote-Initiated GMPLS LSPs
     
        [I-D. draft-crabbe-pce-pce-initiated-lsp] specifies procedures
        that can be used for creation and deletion of PCE-initiated LSPs
        under the active stateful PCE model. However, this specification
        does not address GMPLS requirements outlined in the following:
     
        -  GMPLS support multiple switching capabilities on per TE link
          basis. GMPLS LSP creation requires knowledge of LSP switching
          capability (e.g., TDM, L2SC, OTN-TDM, LSC, etc.) to be used
          [RFC3471], [RFC3473].
     
        -  GMPLS LSP creation requires knowledge of the encoding type
          (e.g., lambda photonic, Ethernet, SONET/ SDH, G709 OTN, etc.)
          to be used by the LSP [RFC3471], [RFC3473].
     
        -  GMPLS LSP creation requires information of the generalized
          payload (G-PID) to be carried by the LSP [RFC3471], [RFC3473].
     
        -  GMPLS LSP creation requires specification of data flow
          specific traffic parameters (also known as Tspec), which are
          technology specific.
     
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        -  GMPLS also specifics support for asymmetric bandwidth
          requests [RFC6387].
     
        -  GMPLS extends the addressing to include unnumbered interface
          identifiers, as defined in [RFC3477].
     
        -  In some technologies path calculation is tightly coupled with
          label selection along the route. For example, path calculation
          in a WDM network may include lambda continuity and/ or lambda
          feasibility constraints and hence a path computed by the PCE
          is associated with a specific lambda (label). Hence, in such
          networks, the label information needs to be provided to a PCC
          in order for a PCE to initiate GMPLS LSPs under the active
          stateful PCE model. I.e., explicit label control may be
          required.
     
        -  GMPLS specifics protection context for the LSP, as defined in
          [RFC4872] and [RFC4873].
     
     3. PCEP Extensions for Remote-Initiated GMPLS LSPs
     
        LSP initiate (PCInitiate) message defined in [I-D. draft-crabbe-
        pce-pce-initiated-lsp] needs to be extended to include GMPLS
        specific PCEP objects as follows:
     
     3.1. Generalized Endpoint in LSP Initiate Message
     
        This document does not modify the usage of END-POINTS object for
        PCE initiated LSPs as specified in [I-D. draft-crabbe-pce-pce-
        initiated-lsp]. It augments the usage as specified below.
     
        END-POINTS object has been extended by [I-D. draft-ietf-pcep-
        gmpls-ext] to include a new object type called "Generalized
        Endpoint". PCInitiate message sent by a PCE to a PCC to trigger
        a GMPLS LSP instantiation SHOULD include the END-POINTS with
        Generalized Endpoint object type. Furthermore, the END-POINTS
        object MUST contain "label request" TLV. The label request TLV
        is used to specify the switching type, encoding type and GPID of
        the LSP being instantiated by the PCE.
     
        The unnumbered endpoint TLV can be used to specify unnumbered
        endpoint addresses for the LSP being instantiated by the PCE.
        The END-POINTS MAY contain other TLVs defined in [I-D. draft-
        ietf-pcep-gmpls-ext].
     
        If the END-POINTS Object of type Generalized Endpoint is missing
        the label request TLV, the PCC MUST send a PCErr message with
        Error-type=6 (Mandatory Object missing) and Error-value= TBA
        (LSP request TLV missing).
     
        If the PCC does not support the END-POINTS Object of type
        Generalized Endpoint, the PCC MUST send a PCErr message with
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        Error-type = 3 (Unknown Object), Error-value = 2(unknown object
        type).
     
     3.2. GENERALIZED-BANDWIDTH object in LSP Initiate Message
     
           LSP initiate message defined in [I-D. draft-crabbe-pce-pce-
        initiated-lsp] can optionally include the BANDWIDTH object.
        However, the following possibilities cannot be represented in
        the BANDWIDTH object:
     
           - Asymmetric bandwidth (different bandwidth in forward and
        reverse direction), as described in [RFC6387].
     
           - Technology specific GMPLS parameters (e.g., Tspec for
        SDH/SONET, G.709, ATM, MEF, etc.) are not supported.
     
        GENERALIZED-BANDWIDTH object has been defined in [I-D. draft-
        ietf-pcep-gmpls-ext] to address the above-mentioned limitation
        of the BANDWIDTH object.
     
        This document specifies the use of GENERALIZED-BANDWIDTH object
        in PCInitiate message. Specifically, GENERALIZED-BANDWIDTH
        object MAY be included in the PCInitiate message. The
        GENERALIZED-BANDWIDTH object in PCInitiate message is used to
        specify technology specific Tspec and asymmetrical bandwidth
        values for the LSP being instantiated by the PCE.
     
     3.3. Protection Attributes in LSP Initiate Message
     
        This document does not modify the usage of LSPA object for PCE
        initiated LSPs as specified in [I-D. draft-crabbe-pce-pce-
        initiated-lsp]. It augments the usage of LSPA object in LSP
        Initiate Message to carry the end-to-end protection context this
        also includes the protection state information.
     
        The LSP Protection Information TLV of LSPA in the PCInitiate
        message can be used to specify protection attributes of the LSP
        being instantiated by the PCE.
     
     3.4. ERO in LSP Initiate Object
     
        This document does not modify the usage of ERO object for PCE
        initiated LSPs as specified in [I-D. draft-crabbe-pce-pce-
        initiated-lsp]. It augments the usage as specified in the
        following sections.
     
     3.4.1. ERO with explicit label control
     
        As mentioned earlier, there are technologies and scenarios where
        active stateful PCE requires explicit label control in order to
        instantiate an LSP.
     
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        Explicit label control (ELC) is a procedure supported by RSVP-
        TE, where the outgoing label(s) is (are) encoded in the ERO. [I-
        D. draft-ietf-pcep-gmpls-ext] extends the <ERO> object of PCEP
        to include explicit label control. The ELC procedure enables the
        PCE to provide such label(s) directly in the path ERO.
     
        The extended ERO object in PCInitiate message can be used to
        specify label along with ERO to PCC for the LSP being
        instantiated by the active stateful PCE.
     
     3.4.2. ERO with Path Keys
     
        There are many scenarios in packet and optical networks where
        the route information of an LSP may not be provided to the PCC
        for confidentiality reasons.  A multi-domain or multi-layer
        network is an example of such networks. Similarly, a GMPLS User-
        Network Interface (UNI) [RFC4208] is also an example of such
        networks.
     
        In such scenarios, ERO containing the entire route cannot be
        provided to PCC (by PCE). Instead, PCE provides an ERO with Path
        Keys to the PCC. For example, in the case UNI interface between
        the router and the optical nodes, the ERO in the LSP Initiate
        Message may be constructed as follows:
     
       - The first hop is a strict hop that provides the egress
          interface information at PCC. This interface information is
          used to get to a network node that can extend the rest of the
          ERO. (Please note that in the cases where the network node is
          not directly connected with the PCC, this part of ERO may
          consist of multiple hops and may be loose).
       - The following(s) hop in the ERO may provide the network node
          with the path key [RFC5520] that can be resolved to get the
          contents of the route towards the destination.
       - There may be further hops but these hops may also be encoded
          with the path keys (if needed).
     
       This document does not change encoding or processing roles for
       the path keys, which are defined in [RFC5520].
     
     3.4.3. Switch Layer Object
     
        [draft-ietf-pce-inter-layer-ext-07] specifies the SWITCH-LAYER
        object which defines and specifies the switching layer (or
        layers) in which a path MUST or MUST NOT be established. A
        switching layer is expressed as a switching type and encoding
        type. [I-D. draft-ietf-pcep-gmpls-ext], which defines the GMPLS
     
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        extensions for PCEP, suggests using the SWITCH-LAYER object.
        Thus, SWITCH-LAYER object can be used in the PCInitiate message
        to specify the switching layer (or layers) of the LSP being
        remotely initiated.
     
     3.5. LSP delegation and cleanup
     
        LSP delegation and cleanup procedure specified in [I-D. draft-
        ietf-pcep-gmpls-ext] are equally applicable to GMPLS LSPs and
        this document does not modify the associated usage.
     
     4. Security Considerations
     
        To be added in future revision of this document.
     
     5. IANA Considerations
     
     5.1. PCEP-Error Object
     
        This document defines the following new Error-Value:
     
        Error-Type  Error Value
     
        6           Error-value=TBA:  LSP Request TLV missing
     
     6. Acknowledgments
     
        The authors would like to thank George Swallow and Jan Medved
        for their comments.
     
     7. References
     
     
     7.1. Normative References
     
         [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
                  Requirement Levels", BCP 14, RFC 2119, March 1997.
     
         [I-D. draft-crabbe-pce-pce-initiated-lsp] Crabbe, E., Minei,
                  I., Sivabalan, S., Varga, R., "PCEP Extensions for
                  PCE-initiated LSP Setup in a Stateful PCE Model",
                  draft-crabbe-pce-pce-initiated-lsp, work in progress.
     
         [RFC5440]  Vasseur, JP., Ed., and JL. Le Roux, Ed., "Path
                  Computation Element (PCE) Communication Protocol
                  (PCEP)", RFC 5440, March 2009.
     
         [RFC5623] Oki, E., Takeda, T., Le Roux, JL., and A. Farrel,
                  "Framework for PCE-Based Inter-Layer MPLS and GMPLS
                  Traffic Engineering", RFC 5623, September 2009.
     
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        [RFC 6107] Shiomoto, K., Ed., and A. Farrel, Ed., "Procedures
                  for Dynamically Signaled Hierarchical Label Switched
                  Paths", RFC 6107, February 2011.
     
     7.2. Informative References
     
         [RFC3471] Berger, L., Ed., "Generalized Multi-Protocol Label
                  Switching (GMPLS) Signaling Functional Description",
                  RFC 3471, January 2003.
     
        [RFC3473] Berger, L., Ed., "Generalized Multi-Protocol Label
                  Switching (GMPLS) Signaling Resource ReserVation
                  Protocol-Traffic Engineering (RSVP-TE) Extensions",
                  RFC 3473, January 2003.
     
        [RFC3477] Kompella, K. and Y. Rekhter, "Signalling Unnumbered
                  Links in Resource ReSerVation Protocol - Traffic
                  Engineering (RSVP-TE)", RFC 3477, January 2003.
     
     
        [RFC4872] Lang, J., Ed., Rekhter, Y., Ed., and D. Papadimitriou,
                  Ed., "RSVP-TE Extensions in Support of End-to-End
                  Generalized Multi-Protocol Label Switching (GMPLS)
                  Recovery", RFC 4872, May 2007.
     
        [RFC4873] Berger, L., Bryskin, I., Papadimitriou, D., and A.
                  Farrel, "GMPLS Segment Recovery", RFC 4873, May 2007.
     
        [RFC4208] Swallow, G., Drake, J., Ishimatsu, H., and Y. Rekhter,
                  "Generalized Multiprotocol Label Switching (GMPLS)
                  User-Network Interface (UNI): Resource ReserVation
                  Protocol-Traffic Engineering (RSVP-TE) Support for the
                  Overlay Model", RFC 4208, October 2005.
     
        [RFC5520] Bradford, R., Ed., Vasseur, JP., and A. Farrel,
                  "Preserving Topology Confidentiality in Inter-Domain
                  Path Computation Using a Path-Key-Based Mechanism",
                  RFC 5520, April 2009.
     
     Author's Addresses
     
     
        Zafar Ali
        Cisco Systems
        Email: zali@cisco.com
     
        Siva Sivabalan
        Cisco Systems
        Email: msiva@cisco.com
     
        Clarence Filsfils
     
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        Cisco Systems
        Email: cfilsfil@cisco.com
     
     
        Robert Varga
        Pantheon Technologies
     
        Victor Lopez
        Telefonica I+D
        Email: vlopez@tid.es
     
        Oscar Gonzalez de Dios
        Telefonica I+D
        Email: ogondio@tid.es
     
        Xian Zhang
        Huawei Technologies
        Email: zhang.xian@huawei.com
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
     
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