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Versions: (draft-sivabalan-pce-policy-identifier) 00 draft-ietf-pce-association-policy

PCE Working Group                                          D. Dhody, Ed.
Internet-Draft                                       Huawei Technologies
Intended status: Standards Track                       S. Sivabalan, Ed.
Expires: May 1, 2017                                 Cisco Systems, Inc.
                                                            S. Litkowski
                                                                  Orange
                                                             J. Tantsura
                                                              Individual
                                                             J. Hardwick
                                                     Metaswitch Networks
                                                        October 28, 2016


     Path Computation Element communication Protocol extension for
                     associating Policies and LSPs
                 draft-dhody-pce-association-policy-00

Abstract

   This document introduces a simple mechanism to associate policies to
   a group of Label Switched Paths (LSPs) via an extension to the Path
   Computation Element (PCE) Communication Protocol (PCEP).

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
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   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
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   This Internet-Draft will expire on May 1, 2017.

Copyright Notice

   Copyright (c) 2016 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



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   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.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   3
   3.  Motivation  . . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Policy based Constraints  . . . . . . . . . . . . . . . .   5
   4.  Overview  . . . . . . . . . . . . . . . . . . . . . . . . . .   5
   5.  Policy Association Group  . . . . . . . . . . . . . . . . . .   5
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   6
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   6
     7.1.  Association object Type Indicators  . . . . . . . . . . .   6
   8.  Manageability Considerations  . . . . . . . . . . . . . . . .   6
     8.1.  Control of Function and Policy  . . . . . . . . . . . . .   6
     8.2.  Information and Data Models . . . . . . . . . . . . . . .   6
     8.3.  Liveness Detection and Monitoring . . . . . . . . . . . .   6
     8.4.  Verify Correct Operations . . . . . . . . . . . . . . . .   7
     8.5.  Requirements On Other Protocols . . . . . . . . . . . . .   7
     8.6.  Impact On Network Operations  . . . . . . . . . . . . . .   7
   9.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   7
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   7
     10.2.  Informative References . . . . . . . . . . . . . . . . .   8
   Appendix A.  Contributor Addresses  . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   [RFC5440] describes the Path Computation Element communication
   Protocol (PCEP) which enables the communication between a Path
   Computation Client (PCC) and a Path Control Element (PCE), or between
   two PCEs based on the PCE architecture [RFC4655].

   PCEP Extensions for Stateful PCE Model [I-D.ietf-pce-stateful-pce]
   describes a set of extensions to PCEP to enable active control of
   MPLS-TE and GMPLS tunnels.  [I-D.ietf-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, thus allowing for a dynamic network.  Currently, the LSPs
   can either be signaled via RSVP-TE or can be segment routed as
   specified in [I-D.ietf-pce-segment-routing].



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   [I-D.ietf-pce-association-group] introduces a generic mechanism to
   create a grouping of LSPs which can then be used to define
   associations between a set of LSPs and a set of attributes (such as
   configuration parameters or behaviors) and is equally applicable to
   the active and passive modes of a stateful PCE or a stateless PCE.

   This document specifies a PCEP extension to associate one or more
   LSPs with policies using the generic association mechanism.

   A PCEP speaker may want to influence the PCEP peer with respect to
   path selection and other policies.  This document describes a PCEP
   extension to associate policies by creating Policy Association Group
   (PAG) and encoding this association in PCEP messages.  The
   specification is applicable to both stateful and stateless PCEP
   sessions.

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].

2.  Terminology

   The following terminology is used in this document.

   LSR:  Label Switch Router.

   MPLS:  Multiprotocol Label Switching.

   PAG:  Policy Association Group.

   PCC:  Path Computation Client.  Any client application requesting a
      path computation to be performed by a Path Computation Element.

   PCE:  Path Computation Element.  An entity (component, application,
      or network node) that is capable of computing a network path or
      route based on a network graph and applying computational
      constraints.

   PCEP:  Path Computation Element Communication Protocol.

3.  Motivation

   Paths computed using PCE MAY be subjected to various policies on both
   PCE and PCC.  For example, in a centralized traffic engineering
   scenario, network operators may instantiate LSPs and specifies
   policies for traffic steering, path monitoring, etc., for some LSPs



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   via the stateful PCE.  Similarly, a PCC may request a user- or
   service-specific policy to be applied at the PCE, such as constraints
   relaxation to meet optimal QoS and resiliency.

   PCEP speaker can use the generic mechanism as per
   [I-D.ietf-pce-association-group] to associate a set of LSPs with
   policy, without the need to know the details of such policies, which
   simplifies network operations, avoids frequent software upgrades, as
   well provides an ability to introduce new policy faster.



                                                            Policy-ID Y
                                                {Service-Specific Policy
                                                       for cosntraint
           Initiate & Monitor LSP                         relaxation}
                    |                                          |
                    |                          PCReq           |
                    V                       {policy-ID Y}      V
                 +-----+                   ----------------> +-----+
      _ _ _ _ _ _| PCE |                  |                  | PCE |
     |           +-----+                  |      ----------> +-----+
     | PCEInitiate                        |     |    PCReq
     |{policy-ID X}                       |     | {policy-ID Y}
     |                                    |     |
     |              .-----.               |     |         .-----.
     |             (       )              |  +----+      (       )
     |         .--(         )--.          |  |PCC1|--.--(         )--.
     V        (                 )         |  +----+ (                 )
   +---+     (                   )        |        (                   )
   |PCC|----(   (G)MPLS network    )    +----+     ( (G)MPLS network   )
   +---+     (                   )     |PCC2|------(                   )
 Policy ID X  (                 )      +----+       (                 )
 {Monitor LSP} '--(         )--'                     '--(         )--'
                   (       )                             (       )
                    '-----'                               '-----'

   Case 1: Policy initiated by PCE        Case 2: Policy initiated by
           and enforced by PCC                    PCC and enforced by
                                                  PCE


         Sample use-cases for carrying policies over PCEP session








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3.1.  Policy based Constraints

   In the context of policy-enabled path computation [RFC5394], path
   computation policies may be applied at both a PCC and a PCE.
   Consider an Label Switch Router (LSR) with a policy enabled PCC, it
   receives a service request via signaling, including over a Network-
   Network Interface (NNI) or User Network Interface (UNI) reference
   point, or receives a configuration request over a management
   interface to establish a service.  The PCC may also apply user- or
   service-specific policies to decide how the path selection process
   should be constrained, that is, which constraints, diversities,
   optimization criterion, and constraint relaxation strategies should
   be applied in order for the service LSP(s) to have a likelihood to be
   successfully established and provide necessary QoS and resilience
   against network failures.  The user- or service-specific policies
   applied to PCC and are then passed to the PCE along with the Path
   computation request, in the form of constraints [RFC5394].

   PCEP speaker can use the generic mechanism as per
   [I-D.ietf-pce-association-group] to associate a set of LSPs with
   policy and its resulting path computation constraints.  This
   simplified the path computation message exchanges.

4.  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.  Grouping can also be used to define association
   between LSPs and policies associated to them.  One new Association
   Type is defined in this document, based on the generic Association
   object -

   o  Association type = TBD1 ("Policy Association Type") for Policy
      Association Group (PAG)

   A PAG can have one or more LSPs and its associated policy(s).  The
   Association ID defined in [I-D.ietf-pce-association-group] is used to
   identify the PAG.

5.  Policy Association Group

   Association groups and their memberships are defined using the
   ASSOCIATION object defined in [I-D.ietf-pce-association-group].  Two
   object types for IPv4 and IPv6 are defined.  The ASSOCIATION object
   includes "Association type" indicating the type of the association
   group.  This document add a new Association type -

   Association type = TBD1 ("Policy Association Type") for PAG.



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   PAG may carry optional TLVs including but not limited to -

   o  VENDOR-INFORMATION-TLV: Used to communicate arbitrary vendor
      specific behavioral information, described in [RFC7470].

6.  Security Considerations

   This document defines one new type for association, which do not add
   any new security concerns beyond those discussed in [RFC5440],
   [I-D.ietf-pce-stateful-pce] and [I-D.ietf-pce-association-group] in
   itself.

   Some deployments may find policy associations and their implications
   as extra sensitive and thus should employ suitable PCEP security
   mechanisms like TCP-AO or [I-D.ietf-pce-pceps].

7.  IANA Considerations

7.1.  Association object Type Indicators

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

   Value     Name                        Reference

   TBD1      Policy Association Type     [This I.D.]

8.  Manageability Considerations

8.1.  Control of Function and Policy

   An operator MUST BE allowed to configure the policy associations at
   PCEP peers and associate it with the LSPs.

8.2.  Information and Data Models

   [RFC7420] describes the PCEP MIB, there are no new MIB Objects for
   this document.

8.3.  Liveness Detection and Monitoring

   Mechanisms defined in this document do not imply any new liveness
   detection and monitoring requirements in addition to those already
   listed in [RFC5440].







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8.4.  Verify Correct Operations

   Mechanisms defined in this document do not imply any new operation
   verification requirements in addition to those already listed in
   [RFC5440].

8.5.  Requirements On Other Protocols

   Mechanisms defined in this document do not imply any new requirements
   on other protocols.

8.6.  Impact On Network Operations

   Mechanisms defined in this document do not have any impact on network
   operations in addition to those already listed in [RFC5440].

9.  Acknowledgments

   A special thanks to author of [I-D.ietf-pce-association-group], this
   document borrow some of the text from it.

10.  References

10.1.  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,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC5440]  Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation
              Element (PCE) Communication Protocol (PCEP)", RFC 5440,
              DOI 10.17487/RFC5440, March 2009,
              <http://www.rfc-editor.org/info/rfc5440>.

   [I-D.ietf-pce-association-group]
              Minei, I., Crabbe, E., Sivabalan, S., Ananthakrishnan, H.,
              Zhang, X., and Y. Tanaka, "PCEP Extensions for
              Establishing Relationships Between Sets of LSPs", draft-
              ietf-pce-association-group-01 (work in progress), July
              2016.

   [I-D.ietf-pce-stateful-pce]
              Crabbe, E., Minei, I., Medved, J., and R. Varga, "PCEP
              Extensions for Stateful PCE", draft-ietf-pce-stateful-
              pce-16 (work in progress), September 2016.





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10.2.  Informative References

   [RFC4655]  Farrel, A., Vasseur, J., and J. Ash, "A Path Computation
              Element (PCE)-Based Architecture", RFC 4655,
              DOI 10.17487/RFC4655, August 2006,
              <http://www.rfc-editor.org/info/rfc4655>.

   [RFC5394]  Bryskin, I., Papadimitriou, D., Berger, L., and J. Ash,
              "Policy-Enabled Path Computation Framework", RFC 5394,
              DOI 10.17487/RFC5394, December 2008,
              <http://www.rfc-editor.org/info/rfc5394>.

   [RFC7420]  Koushik, A., Stephan, E., Zhao, Q., King, D., and J.
              Hardwick, "Path Computation Element Communication Protocol
              (PCEP) Management Information Base (MIB) Module",
              RFC 7420, DOI 10.17487/RFC7420, December 2014,
              <http://www.rfc-editor.org/info/rfc7420>.

   [RFC7470]  Zhang, F. and A. Farrel, "Conveying Vendor-Specific
              Constraints in the Path Computation Element Communication
              Protocol", RFC 7470, DOI 10.17487/RFC7470, March 2015,
              <http://www.rfc-editor.org/info/rfc7470>.

   [I-D.ietf-pce-pceps]
              Lopez, D., Dios, O., Wu, W., and D. Dhody, "Secure
              Transport for PCEP", draft-ietf-pce-pceps-10 (work in
              progress), July 2016.

   [I-D.ietf-pce-pce-initiated-lsp]
              Crabbe, E., Minei, I., Sivabalan, S., and R. Varga, "PCEP
              Extensions for PCE-initiated LSP Setup in a Stateful PCE
              Model", draft-ietf-pce-pce-initiated-lsp-07 (work in
              progress), July 2016.

   [I-D.ietf-pce-segment-routing]
              Sivabalan, S., Medved, J., Filsfils, C., Crabbe, E.,
              Raszuk, R., Lopez, V., Tantsura, J., Henderickx, W., and
              J. Hardwick, "PCEP Extensions for Segment Routing", draft-
              ietf-pce-segment-routing-08 (work in progress), October
              2016.











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Appendix A.  Contributor Addresses

   Qin Wu
   Huawei Technologies
   101 Software Avenue, Yuhua District
   Nanjing, Jiangsu  210012
   China

   EMail: sunseawq@huawei.com

   Clarence Filsfils
   Cisco Systems, Inc.
   Pegasus Parc
   De kleetlaan 6a, DIEGEM  BRABANT 1831
   BELGIUM

   Email: cfilsfil@cisco.com

   Xian Zhang
   Huawei Technologies
   Bantian, Longgang District
   Shenzhen  518129
   P.R.China

   EMail: zhang.xian@huawei.com

   Udayasree Palle
   Huawei Technologies
   Divyashree Techno Park, Whitefield
   Bangalore, Karnataka  560066
   India

   EMail: udayasree.palle@huawei.com


Authors' Addresses

   Dhruv Dhody (editor)
   Huawei Technologies
   Divyashree Techno Park, Whitefield
   Bangalore, Karnataka  560066
   India

   EMail: dhruv.ietf@gmail.com







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   Siva Sivabalan (editor)
   Cisco Systems, Inc.
   2000 Innovation Drive
   Kanata, Ontario  K2K 3E8
   Canada

   EMail: msiva@cisco.com


   Stephane Litkowski
   Orange

   EMail: stephane.litkowski@orange.com


   Jeff Tantsura
   Individual

   EMail: jefftant.ietf@gmail.com


   Jonathan Hardwick
   Metaswitch Networks
   100 Church Street
   Enfield, Middlesex
   UK

   EMail: Jonathan.Hardwick@metaswitch.com























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