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Versions: (draft-takacs-ccamp-asymm-bw-bidir-lsps-bis) 00 01 02 03 RFC 6387

Network Working Group                                          A. Takacs
Internet-Draft                                                  Ericsson
Obsoletes: 5467 (if approved)                                  L. Berger
Intended status: Standards Track                 LabN Consulting, L.L.C.
Expires: August 1, 2011                                      D. Caviglia
                                                                Ericsson
                                                                D. Fedyk
                                                          Alcatel-Lucent
                                                               J. Meuric
                                                   France Telecom Orange
                                                        January 28, 2011


  GMPLS Asymmetric Bandwidth Bidirectional Label Switched Paths (LSPs)
            draft-ietf-ccamp-asymm-bw-bidir-lsps-bis-01.txt

Abstract

   This document defines a method for the support of GMPLS asymmetric
   bandwidth bidirectional Label Switched Paths (LSPs).  The presented
   approach is applicable to any switching technology and builds on the
   original Resource Reservation Protocol (RSVP) model for the transport
   of traffic-related parameters.  This document moves the experiment
   documented in RFC 5467 to the standards track and obsoletes RFC 5467.

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
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   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 August 1, 2011.

Copyright Notice

   Copyright (c) 2011 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



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   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
   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 . . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.1.  Background . . . . . . . . . . . . . . . . . . . . . . . .  3
     1.2.  Approach Overview  . . . . . . . . . . . . . . . . . . . .  4
     1.3.  Conventions Used in This Document  . . . . . . . . . . . .  5
   2.  Generalized Asymmetric Bandwidth Bidirectional LSPs  . . . . .  6
     2.1.  UPSTREAM_FLOWSPEC Object . . . . . . . . . . . . . . . . .  6
       2.1.1.  Procedures . . . . . . . . . . . . . . . . . . . . . .  6
     2.2.  UPSTREAM_TSPEC Object  . . . . . . . . . . . . . . . . . .  6
       2.2.1.  Procedures . . . . . . . . . . . . . . . . . . . . . .  7
     2.3.  UPSTREAM_ADSPEC Object . . . . . . . . . . . . . . . . . .  7
       2.3.1.  Procedures . . . . . . . . . . . . . . . . . . . . . .  7
   3.  Packet Formats . . . . . . . . . . . . . . . . . . . . . . . .  8
   4.  Compatibility  . . . . . . . . . . . . . . . . . . . . . . . . 10
   5.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 11
     5.1.  UPSTREAM_FLOWSPEC Object . . . . . . . . . . . . . . . . . 11
     5.2.  UPSTREAM_TSPEC Object  . . . . . . . . . . . . . . . . . . 11
     5.3.  UPSTREAM_ADSPEC Object . . . . . . . . . . . . . . . . . . 11
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 12
   7.  References . . . . . . . . . . . . . . . . . . . . . . . . . . 13
     7.1.  Normative References . . . . . . . . . . . . . . . . . . . 13
     7.2.  Informative References . . . . . . . . . . . . . . . . . . 13
   Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15

















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1.  Introduction

   GMPLS [RFC3473] introduced explicit support for bidirectional Label
   Switched Paths (LSPs).  The defined support matched the switching
   technologies covered by GMPLS, notably Time Division Multiplexing
   (TDM) and lambdas; specifically, it only supported bidirectional LSPs
   with symmetric bandwidth allocation.  Symmetric bandwidth
   requirements are conveyed using the semantics objects defined in
   [RFC2205] and [RFC2210].

   GMPLS asymmetric bandwidth bidirectional LSPs are bidirectional LSPs
   that have different bandwidth reservations in each direction.
   Support for bidirectional LSPs with asymmetric bandwidth, was
   previously discussed in the context of Ethernet, notably [RFC6060]
   and [RFC6003].  In that context, asymmetric bandwidth support was
   considered to be a capability that was unlikely to be deployed, and
   hence [RFC5467] was published as Experimental.  The MPLS Transport
   Profile, MPLS-TP, requires that asymmetric bandwidth bidirectional
   LSPs be supported, see [RFC5654], and therefore this document is
   being published on the Standards Track.  This document has no
   technical changes from the approach defined in [RFC5467].  This
   document moves the experiment documented in [RFC5467] to the
   standards track and obsoletes [RFC5467].  This document also removes
   the Ethernet technology specific alternative approach discussed in
   the appendix of [RFC5467] and maintains only one approach that is
   suitable for use with any technology.

1.1.  Background

   Bandwidth parameters are transported within RSVP ([RFC2210],
   [RFC3209], and [RFC3473]) via several objects that are opaque to
   RSVP.  While opaque to RSVP, these objects support a particular model
   for the communication of bandwidth information between an RSVP
   session sender (ingress) and receiver (egress).  The original model
   of communication, defined in [RFC2205] and maintained in [RFC3209],
   used the SENDER_TSPEC and ADSPEC objects in Path messages and the
   FLOWSPEC object in Resv messages.  The SENDER_TSPEC object was used
   to indicate a sender's data generation capabilities.  The FLOWSPEC
   object was issued by the receiver and indicated the resources that
   should be allocated to the associated data traffic.  The ADSPEC
   object was used to inform the receiver and intermediate hops of the
   actual resources available for the associated data traffic.

   With the introduction of bidirectional LSPs in [RFC3473], the model
   of communication of bandwidth parameters was implicitly changed.  In
   the context of [RFC3473] bidirectional LSPs, the SENDER_TSPEC object
   indicates the desired resources for both upstream and downstream
   directions.  The FLOWSPEC object is simply confirmation of the



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   allocated resources.  The definition of the ADSPEC object is either
   unmodified and only has meaning for downstream traffic, or is
   implicitly or explicitly ([RFC4606] and [RFC6003]) irrelevant.

1.2.  Approach Overview

   The approach for supporting asymmetric bandwidth bidirectional LSPs
   defined in this document builds on the original RSVP model for the
   transport of traffic-related parameters and GMPLS's support for
   bidirectional LSPs.

   The defined approach is generic and can be applied to any switching
   technology supported by GMPLS.  With this approach, the existing
   SENDER_TSPEC, ADSPEC, and FLOWSPEC objects are complemented with the
   addition of new UPSTREAM_TSPEC, UPSTREAM_ADSPEC, and
   UPSTREAM_FLOWSPEC objects.  The existing objects are used in the
   original fashion defined in [RFC2205] and [RFC2210], and refer only
   to traffic associated with the LSP flowing in the downstream
   direction.  The new objects are used in exactly the same fashion as
   the old objects, but refer to the upstream traffic flow.  Figure 1
   shows the bandwidth-related objects used for asymmetric bandwidth
   bidirectional LSPs.


   |---|        Path        |---|
   | I |------------------->| E |
   | n | -SENDER_TSPEC      | g |
   | g | -ADSPEC            | r |
   | r | -UPSTREAM_FLOWSPEC | e |
   | e |                    | s |
   | s |        Resv        | s |
   | s |<-------------------|   |
   |   | -FLOWSPEC          |   |
   |   | -UPSTREAM_TSPEC    |   |
   |   | -UPSTREAM_ADSPEC   |   |
   |---|                    |---|

   Figure 1: Generic Asymmetric Bandwidth Bidirectional LSPs


   The extensions defined in this document are limited to Point-to-Point
   (P2P) LSPs.  Support for Point-to-Multipoint (P2MP) bidirectional
   LSPs is not currently defined and, as such, not covered in this
   document.







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1.3.  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 [RFC2119].














































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2.  Generalized Asymmetric Bandwidth Bidirectional LSPs

   The setup of an asymmetric bandwidth bidirectional LSP is signaled
   using the bidirectional procedures defined in [RFC3473] together with
   the inclusion of the new UPSTREAM_FLOWSPEC, UPSTREAM_TSPEC, and
   UPSTREAM_ADSPEC objects.

   The new upstream objects carry the same information and are used in
   the same fashion as the existing downstream objects; they differ in
   that they relate to traffic flowing in the upstream direction while
   the existing objects relate to traffic flowing in the downstream
   direction.  The new objects also differ in that they are carried on
   messages traveling in the opposite direction.

2.1.  UPSTREAM_FLOWSPEC Object

   The format of an UPSTREAM_FLOWSPEC object is the same as a FLOWSPEC
   object.  This includes the definition of class types and their
   formats.  The class number of the UPSTREAM_FLOWSPEC object is 120 (of
   the form 0bbbbbbb).

2.1.1.  Procedures

   The Path message of an asymmetric bandwidth bidirectional LSP MUST
   contain an UPSTREAM_FLOWSPEC object and MUST use the bidirectional
   LSP formats and procedures defined in [RFC3473].  The C-Type of the
   UPSTREAM_FLOWSPEC object MUST match the C-Type of the SENDER_TSPEC
   object used in the Path message.  The contents of the
   UPSTREAM_FLOWSPEC object MUST be constructed using a format and
   procedures consistent with those used to construct the FLOWSPEC
   object that will be used for the LSP, e.g., [RFC2210] or [RFC4328].

   Nodes processing a Path message containing an UPSTREAM_FLOWSPEC
   object MUST use the contents of the UPSTREAM_FLOWSPEC object in the
   upstream label and the resource allocation procedure defined in
   Section 3.1 of [RFC3473].  Consistent with [RFC3473], a node that is
   unable to allocate a label or internal resources based on the
   contents of the UPSTREAM_FLOWSPEC object MUST issue a PathErr message
   with a "Routing problem/MPLS label allocation failure" indication.

2.2.  UPSTREAM_TSPEC Object

   The format of an UPSTREAM_TSPEC object is the same as a SENDER_TSPEC
   object.  This includes the definition of class types and their
   formats.  The class number of the UPSTREAM_TSPEC object is 121 (of
   the form 0bbbbbbb).





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2.2.1.  Procedures

   The UPSTREAM_TSPEC object describes the traffic flow that originates
   at the egress.  The UPSTREAM_TSPEC object MUST be included in any
   Resv message that corresponds to a Path message containing an
   UPSTREAM_FLOWSPEC object.  The C-Type of the UPSTREAM_TSPEC object
   MUST match the C-Type of the corresponding UPSTREAM_FLOWSPEC object.
   The contents of the UPSTREAM_TSPEC object MUST be constructed using a
   format and procedures consistent with those used to construct the
   FLOWSPEC object that will be used for the LSP, e.g., [RFC2210] or
   [RFC4328].  The contents of the UPSTREAM_TSPEC object MAY differ from
   contents of the UPSTREAM_FLOWSPEC object based on application data
   transmission requirements.

   When an UPSTREAM_TSPEC object is received by an ingress, the ingress
   MAY determine that the original reservation is insufficient to
   satisfy the traffic flow.  In this case, the ingress MAY issue a Path
   message with an updated UPSTREAM_FLOWSPEC object to modify the
   resources requested for the upstream traffic flow.  This modification
   might require the LSP to be re-routed, and in extreme cases might
   result in the LSP being torn down when sufficient resources are not
   available.

2.3.  UPSTREAM_ADSPEC Object

   The format of an UPSTREAM_ADSPEC object is the same as an ADSPEC
   object.  This includes the definition of class types and their
   formats.  The class number of the UPSTREAM_ADSPEC object is 122 (of
   the form 0bbbbbbb).

2.3.1.  Procedures

   The UPSTREAM_ADSPEC object MAY be included in any Resv message that
   corresponds to a Path message containing an UPSTREAM_FLOWSPEC object.
   The C-Type of the UPSTREAM_TSPEC object MUST be consistent with the
   C-Type of the corresponding UPSTREAM_FLOWSPEC object.  The contents
   of the UPSTREAM_ADSPEC object MUST be constructed using a format and
   procedures consistent with those used to construct the ADSPEC object
   that will be used for the LSP, e.g., [RFC2210] or [RFC6003].  The
   UPSTREAM_ADSPEC object is processed using the same procedures as the
   ADSPEC object and, as such, MAY be updated or added at transit nodes.










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3.  Packet Formats

   This section presents the RSVP message-related formats as modified by
   this section.  This document modifies formats defined in [RFC2205],
   [RFC3209], and [RFC3473].  See [RFC5511] for the syntax used by RSVP.
   Unmodified formats are not listed.  Three new objects are defined in
   this section:


         Object name            Applicable RSVP messages
         ---------------        ------------------------
         UPSTREAM_FLOWSPEC      Path, PathTear, PathErr, and Notify
                                    (via sender descriptor)
         UPSTREAM_TSPEC         Resv, ResvConf, ResvTear, ResvErr, and
                                    Notify (via flow descriptor list)
         UPSTREAM_ADSPEC        Resv, ResvConf, ResvTear, ResvErr, and
                                    Notify (via flow descriptor list)

   The format of the sender description for bidirectional asymmetric
   LSPs is:


         <sender descriptor> ::=  <SENDER_TEMPLATE> <SENDER_TSPEC>
                                  [ <ADSPEC> ]
                                  [ <RECORD_ROUTE> ]
                                  [ <SUGGESTED_LABEL> ]
                                  [ <RECOVERY_LABEL> ]
                                  <UPSTREAM_LABEL>
                                  <UPSTREAM_FLOWSPEC>


   The format of the flow descriptor list for bidirectional asymmetric
   LSPs is:


















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      <flow descriptor list> ::= <FF flow descriptor list>
                               | <SE flow descriptor>

      <FF flow descriptor list> ::= <FLOWSPEC>
                               <UPSTREAM_TSPEC> [ <UPSTREAM_ADSPEC> ]
                               <FILTER_SPEC>
                               <LABEL> [ <RECORD_ROUTE> ]
                               | <FF flow descriptor list>
                               <FF flow descriptor>

      <FF flow descriptor> ::= [ <FLOWSPEC> ]
                               [ <UPSTREAM_TSPEC>] [ <UPSTREAM_ADSPEC> ]
                               <FILTER_SPEC> <LABEL>
                               [ <RECORD_ROUTE> ]

      <SE flow descriptor> ::= <FLOWSPEC>
                               <UPSTREAM_TSPEC> [ <UPSTREAM_ADSPEC> ]
                               <SE filter spec list>

      <SE filter spec list> is unmodified by this document.































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4.  Compatibility

   This extension reuses and extends semantics and procedures defined in
   [RFC2205], [RFC3209], and [RFC3473] to support bidirectional LSPs
   with asymmetric bandwidth.  To indicate the use of asymmetric
   bandwidth, three new objects are defined.  Each of these objects is
   defined with class numbers in the form 0bbbbbbb.  Per [RFC2205],
   nodes not supporting this extension will not recognize the new class
   numbers and should respond with an "Unknown Object Class" error.  The
   error message will propagate to the ingress, which can then take
   action to avoid the path with the incompatible node or may simply
   terminate the session.







































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5.  IANA Considerations

   IANA has assigned new values for namespaces defined in this section
   and reviewed in this subsection.

   The IANA has made the assignments described below in the "Class
   Names, Class Numbers, and Class Types" section of the "RSVP
   PARAMETERS" registry.

5.1.  UPSTREAM_FLOWSPEC Object

   A new class named UPSTREAM_FLOWSPEC has been created in the 0bbbbbbb
   range (120) with the following definition:

         Class Types or C-types:

         Same values as FLOWSPEC object (C-Num 9)

5.2.  UPSTREAM_TSPEC Object

   A new class named UPSTREAM_TSPEC has been created in the 0bbbbbbb
   range (121) with the following definition:

         Class Types or C-types:

         Same values as SENDER_TSPEC object (C-Num 12)

5.3.  UPSTREAM_ADSPEC Object

   A new class named UPSTREAM_ADSPEC has been created in the 0bbbbbbb
   range (122) with the following definition:

         Class Types or C-types:

         Same values as ADSPEC object (C-Num 13)
















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6.  Security Considerations

   This document introduces new message objects for use in GMPLS
   signaling [RFC3473] -- specifically the UPSTREAM_TSPEC,
   UPSTREAM_ADSPEC, and UPSTREAM_FLOWSPEC objects.  These objects
   parallel the existing SENDER_TSPEC, ADSPEC, and FLOWSPEC objects but
   are used in the opposite direction.  As such, any vulnerabilities
   that are due to the use of the old objects now apply to messages
   flowing in the reverse direction.

   From a message standpoint, this document does not introduce any new
   signaling messages or change the relationship between LSRs that are
   adjacent in the control plane.  As such, this document introduces no
   additional message- or neighbor-related security considerations.

   See [RFC3473] for relevant security considerations, and [RFC5920] for
   a more general discussion on RSVP-TE security discussions.


































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7.  References

7.1.  Normative References

   [RFC2205]  Braden, R., Ed., Zhang, L., Berson, S., Herzog, S.,
              and S. Jamin, "Resource ReSerVation Protocol (RSVP)
              -- Version 1 Functional Specification", RFC 2205,
              September 1997.


   [RFC2210]   Wroclawski, J., "The Use of RSVP with IETF Integrated
               Services", RFC 2210, September 1997.


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

7.2.  Informative References

   [RFC6060]   Fedyk, D., et al "Generalized Multiprotocol Label
               Switching (GMPLS) Control of Ethernet Provider
               Backbone Traffic Engineering (PBB-TE)",
               RFC 6060, 2011.


   [RFC6003]   Papadimitriou, D., "MEF Ethernet Traffic Parameters,"
               RFC 6003, October 2008.


   [RFC5654]   B. Niven-Jenkins, Ed., D. Brungard, Ed. and
               M. Betts, Ed., "Requirements of an MPLS Transport
               Profile," RFC 5654, September 2009.








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   [RFC4606]   Mannie, E. and D. Papadimitriou, "Generalized Multi-
               Protocol Label Switching (GMPLS) Extensions for
               Synchronous Optical Network (SONET) and Synchronous
               Digital Hierarchy (SDH) Control", RFC 4606, August
               2006.


   [RFC4328]   Papadimitriou, D., Ed., "Generalized Multi-Protocol
               Label Switching (GMPLS) Signaling Extensions for
               G.709 Optical Transport Networks Control", RFC 4328,
               January 2006.


   [RFC5511]   Farrel, A. "Reduced Backus-Naur Form (RBNF) A Syntax
               Used in Various Protocol Specifications", RFC 5511,
               April 2009.


   [RFC5920]   Fang, L., Ed., "Security Framework for MPLS and
               GMPLS Networks", RFC 5920, July 2010.


   [RFC5467]   L. Berger, A. Takacs, D. Caviglia, D. Fedyk and
               J. Meuric, "GMPLS Asymmetric Bandwidth
               Bidirectional Label Switched Paths (LSPs),"
               RFC 5467, March 2009.

























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Authors' Addresses

   Attila Takacs
   Ericsson
   Laborc u. 1.
   Budapest,   1037
   Hungary

   Email: attila.takacs@ericsson.com


   Lou Berger
   LabN Consulting, L.L.C.

   Email: lberger@labn.net


   Diego Caviglia
   Ericsson
   Via A. Negrone 1/A
   Genova-Sestri Ponente,
   Italy

   Phone: +390106003738
   Fax:
   Email: diego.caviglia@ericsson.com


   Don Fedyk
   Alcatel-Lucent
   Groton, MA
   USA

   Email: donald.fedyk@alcatel-lucent.com


   Julien Meuric
   France Telecom Orange
   2, avenue Pierre Marzin
   Lannion Cedex,   22307
   France

   Email: julien.meuric@orange-ftgroup.com








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