Internet Engineering Task Force (IETF)                  C. Margaria, Ed.
Request for Comments: 7570                                       Juniper
Category: Standards Track                                  G. Martinelli
ISSN: 2070-1721                                                    Cisco
                                                               S. Balls
                                                              B. Wright
                                                             Metaswitch
                                                              July 2015


Label Switched Path (LSP) Attribute in the Explicit Route Object (ERO)

Abstract

  RFC 5420 extends RSVP-TE to specify or record generic attributes that
  apply to the whole of the path of a Label Switched Path (LSP).  This
  document defines an extension to the RSVP Explicit Route Object (ERO)
  and Record Route Object (RRO) to allow them to specify or record
  generic attributes that apply to a given hop.

Status of This Memo

  This is an Internet Standards Track document.

  This document is a product of the Internet Engineering Task Force
  (IETF).  It represents the consensus of the IETF community.  It has
  received public review and has been approved for publication by the
  Internet Engineering Steering Group (IESG).  Further information on
  Internet Standards is available in Section 2 of RFC 5741.

  Information about the current status of this document, any errata,
  and how to provide feedback on it may be obtained at
  http://www.rfc-editor.org/info/rfc7570.

Copyright Notice

  Copyright (c) 2015 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
  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.



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Table of Contents

  1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
    1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   3
  2.  ERO Hop Attributes Subobject  . . . . . . . . . . . . . . . .   3
    2.1.  Encoding  . . . . . . . . . . . . . . . . . . . . . . . .   3
    2.2.  Hop Attributes TLVs . . . . . . . . . . . . . . . . . . .   4
    2.3.  Procedures  . . . . . . . . . . . . . . . . . . . . . . .   4
  3.  RRO Hop Attributes Subobject  . . . . . . . . . . . . . . . .   6
    3.1.  Encoding  . . . . . . . . . . . . . . . . . . . . . . . .   6
    3.2.  Procedures  . . . . . . . . . . . . . . . . . . . . . . .   6
      3.2.1.  Subobject Presence Rule . . . . . . . . . . . . . . .   6
      3.2.2.  Reporting Compliance with ERO Hop Attributes  . . . .   7
      3.2.3.  Compatibility with RRO Attributes Subobject . . . . .   7
  4.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   8
    4.1.  ERO Hop Attributes Subobject  . . . . . . . . . . . . . .   8
    4.2.  RRO Hop Attributes Subobject  . . . . . . . . . . . . . .   8
    4.3.  Existing Attribute Flags  . . . . . . . . . . . . . . . .   8
    4.4.  Existing LSP Attribute TLVs . . . . . . . . . . . . . . .  10
  5.  Security Considerations . . . . . . . . . . . . . . . . . . .  10
  6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  11
    6.1.  Normative References  . . . . . . . . . . . . . . . . . .  11
    6.2.  Informative References  . . . . . . . . . . . . . . . . .  13
  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . .  14
  Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  15

1.  Introduction

  Generalized MPLS (GMPLS) Traffic Engineering (TE) Label Switched
  Paths (LSPs) can be route constrained by making use of the Explicit
  Route Object (ERO) and related subobjects as defined in [RFC3209],
  [RFC3473], [RFC3477], [RFC4873], [RFC4874], [RFC5520], and [RFC5553].
  Several documents have identified the need for attributes that can be
  targeted at specific hops in the path of an LSP, including [RFC6163],
  [WSON-SIG], [RFC7571], or [OBJ-FUN].  This document provides a
  generic mechanism for use by these other documents.

  RSVP already supports generic extension of LSP attributes in
  [RFC5420].  In order to support current and future ERO constraint
  extensions, this document provides a mechanism to define per-hop
  attributes.

  The document describes a generic mechanism for carrying information
  related to specific nodes when signaling an LSP.  This document does
  not restrict what that information can be used for.  The defined
  approach builds on LSP attributes defined in [RFC5420] and enables





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  attributes to be expressed in ERO and Secondary Explicit Route
  Objects (SEROs).  A new ERO subobject is defined, containing a list
  of generic per-hop attributes.

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 RFC 2119 [RFC2119].

2.  ERO Hop Attributes Subobject

  The ERO Hop Attributes subobject is OPTIONAL.  If used, it is carried
  in the ERO or SERO.  The subobject uses the standard format of an ERO
  subobject.

2.1.  Encoding

  The length is variable and content is a list of Hop Attributes TLVs
  defined in Section 2.2.  The size of the ERO subobject limits the
  size of the Hop Attributes TLV to 250 bytes.  The typical size of
  currently defined and forthcoming LSP_ATTRIBUTE TLVs applicable to a
  specific hop (WSON_SIGNALING, Objective Function (OF), and Metric) is
  not foreseen to exceed this limit.

  The ERO Hop Attributes subobject is defined as follows:

     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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |L|    Type     |     Length    |    Reserved                 |R|
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     //                  Hop Attributes TLVs                        //
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  The L, Type, and Length parameters are as defined in [RFC3209],
  Section 4.3.3.  The L bit MUST be set to 0.  The Type for the ERO Hop
  Attributes subobject is 35.  The Hop Attributes TLVs are encoded as
  defined in Section 2.2.

  Reserved:  Reserved MUST be set to 0 when the subobject is inserted
     in the ERO, MUST NOT be changed when a node processes the ERO, and
     MUST be ignored on the node addressed by the preceding ERO
     subobjects.





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  R: This bit reflects the LSP_REQUIRED_ATTRIBUTE and LSP_ATTRIBUTE
     semantic defined in [RFC5420].  When set, it indicates required
     hop attributes to be processed by the node.  When cleared, it
     indicates that the hop attributes are not required as described in
     Section 2.3.

  Hop Attributes TLVs:  The TLVs as defined in Section 2.2.

2.2.  Hop Attributes TLVs

  ERO attributes carried by the new objects defined in this document
  are encoded within TLVs.  Each object MAY contain one or more TLVs.
  There are no ordering rules for TLVs, and interpretation SHOULD NOT
  be placed on the order in which TLVs are received.  The TLV format is
  defined in [RFC5420], Section 3.

  The Attribute Flags TLV defined in [RFC5420] is carried in an ERO Hop
  Attributes subobject.  Flags set in the Attribute Flags TLV [RFC5420]
  carried in an ERO Hop Attributes subobject SHALL be interpreted in
  the context of the received ERO.  Only a subset of defined flags are
  defined as valid for use in Attribute Flags TLV carried in an ERO Hop
  Attributes subobject.  Invalid flags SHALL be silently ignored.
  Unknown flags SHOULD trigger the generation of a PathErr with Error
  Code "Unknown Attributes Bit" as defined in [RFC5420], Section 5.2.
  The set of valid flags are defined in Section 4.3.

  The presence and ordering rule of the Attribute Flags TLV in an ERO
  Hop Attributes subobject is defined by each Flag.  A document
  defining a flag to be used in an Attribute Flags TLV carried in the
  ERO Hop Attributes subobject has to describe:

  o  after which kinds of ERO subobject the flag is valid,

  o  if ordering of the flag and other ERO subobjects associated with
     the same hop (e.g., Label subobjects) is significant,

  o  if ordering is significant, how the flag is interpreted in
     association with the preceding subobjects, and

  o  any flag modification rules that might apply.

2.3.  Procedures

  As described in [RFC3209], the ERO is managed as a list of subobjects
  each identifying a specific entity, an abstract node, or a link that
  defines a waypoint in the network path.  Identifying subobjects of
  various types are defined in [RFC3209], [RFC3477], [RFC4873],
  [RFC4874], [RFC5520], and [RFC5553].



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  [RFC3473] modified the ERO list by allowing one or two Label
  subobjects to be interposed in the list after a subobject identifying
  a link.  One or more ERO Hop Attributes subobjects applicable to a
  particular hop MAY be inserted directly after any of the existing
  identifying subobjects defined in[RFC3209], [RFC3477], [RFC4873],
  [RFC4874], [RFC5520], and [RFC5553].  If any Label subobjects are
  present for a hop, the ERO Hop Attributes subobject(s) MAY also be
  inserted after the Label subobjects.

  The attributes specified in an ERO Hop Attributes subobject apply to
  the immediately preceding subobject(s) in the ERO subobject list.

  A document defining a specific Hop Attributes TLV has to describe:

  o  after which kinds of ERO subobject they are valid,

  o  if ordering of the Hop Attributes subobject and other ERO
     subobjects associated with the same hop (e.g., Label subobjects)
     is significant,

  o  if ordering is significant, how the attribute is interpreted in
     association with the preceding ERO subobjects, and

  o  any TLV modification rules that might apply.

  For instance, subobject presence rules can be defined by describing
  rules similar to [RFC4990], Section 6.1.

  If a node is processing an ERO Hop Attributes subobject and does not
  support the handling of the subobject, it will behave as described in
  [RFC3209] when an unrecognized ERO subobject is encountered.  This
  node will return a PathErr with Error Code "Routing Error" and Error
  Value "Bad EXPLICIT_ROUTE object" with the EXPLICIT_ROUTE object
  included, truncated (on the left) to the offending unrecognized
  subobject.

  When the R bit is set, a node MUST examine the attributes TLV present
  in the subobject following the rules described in [RFC5420],
  Section 5.2.  When the R bit is not set, a node MUST examine the
  attributes TLV present in the subobject following the rules described
  in [RFC5420], Section 4.2.

  A node processing an ERO Hop Attributes subobject with a Hop
  Attributes TLV longer than the ERO subobject SHOULD return a PathErr
  with Error Code "Routing Error" and Error Value "Bad EXPLICIT_ROUTE
  object" with the EXPLICIT_ROUTE object included, truncated (on the
  left) to the offending malformed subobject.  A processing node MUST




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  NOT originate a Hop Attributes TLV longer than the ERO Hop Attributes
  subobject.  The processing of the Hop Attributes TLVs SHOULD be
  described in the documents defining them.

3.  RRO Hop Attributes Subobject

  In some cases, it is important to determine if an OPTIONAL hop
  attribute has been processed by a node.

3.1.  Encoding

  The RRO Hop Attributes subobject is OPTIONAL.  If used, it is carried
  in the RECORD_ROUTE object.  The subobject uses the standard format
  of an RRO subobject.

  The RRO Hop Attributes subobject is defined as follows:

      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     |     Length    |    Reserved                   |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                                                               |
     //                  Hop Attributes TLVs                        //
     |                                                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  The Type and Length parameters are as defined in [RFC3209],
  Section 4.4.1.  The Type for the RRO Hop Attributes subobject is 35.
  The Hop Attributes TLVs are encoded as defined in Section 2.2.

  Reserved:  Reserved MUST be set to 0 when the subobject is inserted
     in the RRO, MUST NOT be changed when a node processes the RRO, and
     MUST be ignored on the node addressed by the preceding RRO
     subobjects.

  Hop Attributes TLVs:  The processed or additional Hop Attributes
     TLVs, using the format defined in Section 2.2.

3.2.  Procedures

3.2.1.  Subobject Presence Rule

  The RRO rules defined in [RFC3209] are not changed.  The RRO Hop
  Attributes subobject MUST be pushed after the RRO Attributes
  subobject (if present) as defined in [RFC5420].  The RRO Hop
  Attributes subobject MAY be present between a pair of subobjects
  identifying the Label Switching Router (LSR) or links.  Unless local



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  policy applies, all such subobjects SHOULD be forwarded unmodified by
  transit LSRs.

  It is noted that a node (e.g., a domain edge node) MAY edit the RRO
  to prune/modify the RRO, including the RRO Hop Attributes subobject
  before forwarding due to confidentiality policy or other reasons (for
  instance, RRO size reduction).

3.2.2.  Reporting Compliance with ERO Hop Attributes

  To report that an ERO hop attribute has been considered, or to report
  an additional attribute, an LSR can add a RRO Hop Attributes
  subobject with the Hop Attributes TLV, which describes the attribute
  to be reported.  The requirement to report compliance MUST be
  specified in the document that defines the usage of a hop attribute.

3.2.3.  Compatibility with RRO Attributes Subobject

  The RRO Hop Attributes subobject extends the capability of the RRO
  Attributes subobject defined in [RFC5420], Section 7.2 by allowing
  the node to report the attribute value.  The mechanism defined in
  this document is compatible with the RRO Attributes subobject using
  the following procedures.

  For LSP attributes signaled in the LSP_ATTRIBUTES or
  LSP_REQUIRED_ATTRIBUTES objects, a node SHOULD use the RRO Attributes
  subobject to report processing of those attributes.

  For LSP attributes signaled in the ERO Hop Attributes subobject and
  not in the LSP_ATTRIBUTES or LSP_REQUIRED_ATTRIBUTES objects, if a
  node desires to report the attributes, it SHOULD use the RRO Hop
  Attributes subobject and SHOULD NOT use the RRO Attributes subobject.
  Ingress nodes not supporting the RRO Hop Attributes subobject will
  drop the information, as described in [RFC3209], Section 4.4.5.

  A node can use the RRO Hop Attributes subobject to report an LSP
  attribute signaled in LSP_ATTRIBUTES or LSP_REQUIRED_ATTRIBUTES only
  if the following conditions are met:

     The attribute and its corresponding flag is allowed on both the
     LSP_ATTRIBUTES or LSP_REQUIRED_ATTRIBUTES and LSP Hop Attributes
     subobject.

     The reporting of an LSP attribute signaled in LSP_ATTRIBUTES or
     LSP_REQUIRED_ATTRIBUTES in the RRO Hop Attribute is specified in
     the document defining that LSP attribute.





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4.  IANA Considerations

4.1.  ERO Hop Attributes Subobject

  IANA manages the "Resource Reservation Protocol (RSVP) Parameters"
  registry located at
  <http://www.iana.org/assignments/rsvp-parameters>.  Per this
  document, IANA has made an allocation in the Sub-object type 20
  EXPLICIT_ROUTE - Type 1 Explicit Route registry.

  This document introduces a new ERO subobject:

            Value  Description       Reference
            ------ ----------------- ------------------------
            35     Hop Attributes    This document, Section 2

4.2.  RRO Hop Attributes Subobject

  IANA manages the "Resource Reservation Protocol (RSVP) Parameters"
  registry located at
  <http://www.iana.org/assignments/rsvp-parameters>.  Per this
  document, IANA has made an allocation in the Sub-object type 21
  ROUTE_RECORD - Type 1 Route Record registry.  This value is the same
  as that in Section 4.1.

  This document introduces a new RRO subobject:

            Value  Description       Reference
            ------ ----------------- ------------------------
            35     Hop Attributes    This document, Section 3

4.3.  Existing Attribute Flags

  IANA manages the "Attribute Flags" registry as part of the "Resource
  Reservation Protocol-Traffic Engineering (RSVP-TE) Parameters"
  registry located at
  <http://www.iana.org/assignments/rsvp-te-parameters>.  A new column
  in the registry is introduced by this document.  This column
  indicates if the flag is permitted to be used in an Attribute Flags
  TLV carried in the ERO Hop Attributes subobject.  The column uses the
  heading "ERO" and the registry has been updated as follows:










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   Bit Name                 Attribute Attribute RRO ERO Reference
   No.                      FlagsPath FlagsResv
   0   End-to-end re-       Yes       No        No  No  [RFC4920]
       routing                                          [RFC5420]
                                                        This Document
   1   Boundary re-routing  Yes       No        No  No  [RFC4920]
                                                        [RFC5420]
                                                        This Document
   2   Segment-based re-    Yes       No        No  No  [RFC4920]
       routing                                          [RFC5420]
                                                        This Document
   3   LSP Integrity        Yes       No        No  No  [RFC4875]
       Required
                                                        This Document
   4   Contiguous LSP       Yes       No        Yes No  [RFC5151]
                                                        This Document
   5   LSP stitching        Yes       No        Yes No  [RFC5150]
       desired
                                                        This Document
   6   Pre-Planned LSP Flag Yes       No        No  No  [RFC6001]
                                                        This Document
   7   Non-PHP behavior     Yes       No        Yes No  [RFC6511]
       flag
                                                        This Document
   8   OOB mapping flag     Yes       No        Yes No  [RFC6511]
                                                        This Document
   9   Entropy Label        Yes       Yes       No  No  [RFC6790]
       Capability
                                                        This Document
   10  OAM MEP entities     Yes       Yes       Yes No  [RFC7260]
       desired
                                                        This Document
   11  OAM MIP entities     Yes       Yes       Yes No  [RFC7260]
       desired
                                                        This Document
   12  SRLG collection Flag Yes       Yes       Yes No  [SRLG-COLLECT]
       (TEMPORARY -                                     This Document
       registered
       2014-09-11, expires
       2015-09-11)

  New allocation requests to this registry SHALL indicate the value to
  be used in the ERO column.








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4.4.  Existing LSP Attribute TLVs

  IANA manages the "Resource Reservation Protocol-Traffic Engineering
  (RSVP-TE) Parameters" registry located at
  <http://www.iana.org/assignments/rsvp-te-parameters>.  The
  "Attributes TLV Space" registry manages the following attributes, as
  defined in [RFC5420]:

  o  TLV Type (T-field value)

  o  TLV Name

  o  Whether allowed on LSP_ATTRIBUTES object

  o  Whether allowed on LSP_REQUIRED_ATTRIBUTES object

  Per this document, IANA has added the following information for each
  TLV in the RSVP TLV type identifier registry.

  o  Whether allowed on LSP Hop Attributes ERO subobject

  The existing registry has been modified for existing TLVs as follows.
  The following abbreviations are used below:

  LSP_A:  Whether allowed on LSP_ATTRIBUTES object.

  LSP_RA:  Whether allowed on LSP_REQUIRED_ATTRIBUTES object.

  HOP_A:  Whether allowed on LSP Hop Attributes subobject.

        T Name                  LSP_A LSP_RA HOP_A Ref.
        - --------------------- ----- ------ ----- --------------
        1 Attribute Flags       Yes   Yes    Yes   [RFC5420]
                                                   This Document
        2 Service ID TLV        Yes   No     No    [RFC6060]
                                                   This Document
        3 OAM Configuration TLV Yes   Yes    No    [RFC7260]
                                                   This Document

5.  Security Considerations

  This document adds a new subobject in the EXPLICIT_ROUTE and the
  ROUTE_RECORD objects carried in RSVP messages used in MPLS and GMPLS
  signaling.  It builds on mechanisms defined in [RFC3209] and
  [RFC5420] and does not introduce any new security.  The existing
  security considerations described in [RFC2205], [RFC3209], [RFC3473],
  and [RFC5420] do apply.




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  As with any RSVP-TE signaling request, the procedures defined in this
  document permit the transfer and reporting of functional preferences
  on a specific node.  The mechanism added in this document does allow
  more control of LSP attributes at a given node.  A node SHOULD check
  the hop attributes against its policies and admission procedures as
  it does with other inputs.  A node MAY reject the message using
  existing RSVP Error Codes like "Policy Control Failure" or "Admission
  Control Failure".  The node MAY also, depending on the specific TLV
  procedures, modify the requested attribute.  This can reveal
  information about the LSP request and status to anyone with
  unauthorized access.  The mechanism described in this document does
  not contribute to this issue, which can be only resolved by
  encrypting the content of the whole signaling message.

  In addition, the reporting of attributes using the RRO can reveal
  details about the node that the operator wishes to remain
  confidential.  The same strategy and policies that apply to other RRO
  subobjects also apply to this new mechanism.  It is RECOMMENDED that
  domain boundary policies take the releasing of RRO hop attributes
  into consideration.

6.  References

6.1.  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>.

  [RFC2205]  Braden, R., Ed., Zhang, L., Berson, S., Herzog, S., and S.
             Jamin, "Resource ReSerVation Protocol (RSVP) -- Version 1
             Functional Specification", RFC 2205, DOI 10.17487/RFC2205,
             September 1997, <http://www.rfc-editor.org/info/rfc2205>.

  [RFC3209]  Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V.,
             and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP
             Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001,
             <http://www.rfc-editor.org/info/rfc3209>.

  [RFC3473]  Berger, L., Ed., "Generalized Multi-Protocol Label
             Switching (GMPLS) Signaling Resource ReserVation Protocol-
             Traffic Engineering (RSVP-TE) Extensions", RFC 3473,
             DOI 10.17487/RFC3473, January 2003,
             <http://www.rfc-editor.org/info/rfc3473>.






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  [RFC3477]  Kompella, K. and Y. Rekhter, "Signalling Unnumbered Links
             in Resource ReSerVation Protocol - Traffic Engineering
             (RSVP-TE)", RFC 3477, DOI 10.17487/RFC3477, January 2003,
             <http://www.rfc-editor.org/info/rfc3477>.

  [RFC4873]  Berger, L., Bryskin, I., Papadimitriou, D., and A. Farrel,
             "GMPLS Segment Recovery", RFC 4873, DOI 10.17487/RFC4873,
             May 2007, <http://www.rfc-editor.org/info/rfc4873>.

  [RFC4874]  Lee, CY., Farrel, A., and S. De Cnodder, "Exclude Routes -
             Extension to Resource ReserVation Protocol-Traffic
             Engineering (RSVP-TE)", RFC 4874, DOI 10.17487/RFC4874,
             April 2007, <http://www.rfc-editor.org/info/rfc4874>.

  [RFC4875]  Aggarwal, R., Ed., Papadimitriou, D., Ed., and S.
             Yasukawa, Ed., "Extensions to Resource Reservation
             Protocol - Traffic Engineering (RSVP-TE) for Point-to-
             Multipoint TE Label Switched Paths (LSPs)", RFC 4875,
             DOI 10.17487/RFC4875, May 2007,
             <http://www.rfc-editor.org/info/rfc4875>.

  [RFC4920]  Farrel, A., Ed., Satyanarayana, A., Iwata, A., Fujita, N.,
             and G. Ash, "Crankback Signaling Extensions for MPLS and
             GMPLS RSVP-TE", RFC 4920, DOI 10.17487/RFC4920, July 2007,
             <http://www.rfc-editor.org/info/rfc4920>.

  [RFC5150]  Ayyangar, A., Kompella, K., Vasseur, JP., and A. Farrel,
             "Label Switched Path Stitching with Generalized
             Multiprotocol Label Switching Traffic Engineering (GMPLS
             TE)", RFC 5150, DOI 10.17487/RFC5150, February 2008,
             <http://www.rfc-editor.org/info/rfc5150>.

  [RFC5151]  Farrel, A., Ed., Ayyangar, A., and JP. Vasseur, "Inter-
             Domain MPLS and GMPLS Traffic Engineering -- Resource
             Reservation Protocol-Traffic Engineering (RSVP-TE)
             Extensions", RFC 5151, DOI 10.17487/RFC5151, February
             2008, <http://www.rfc-editor.org/info/rfc5151>.

  [RFC5420]  Farrel, A., Ed., Papadimitriou, D., Vasseur, JP., and A.
             Ayyangarps, "Encoding of Attributes for MPLS LSP
             Establishment Using Resource Reservation Protocol Traffic
             Engineering (RSVP-TE)", RFC 5420, DOI 10.17487/RFC5420,
             February 2009, <http://www.rfc-editor.org/info/rfc5420>.








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  [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,
             DOI 10.17487/RFC5520, April 2009,
             <http://www.rfc-editor.org/info/rfc5520>.

  [RFC5553]  Farrel, A., Ed., Bradford, R., and JP. Vasseur, "Resource
             Reservation Protocol (RSVP) Extensions for Path Key
             Support", RFC 5553, DOI 10.17487/RFC5553, May 2009,
             <http://www.rfc-editor.org/info/rfc5553>.

  [RFC6001]  Papadimitriou, D., Vigoureux, M., Shiomoto, K., Brungard,
             D., and JL. Le Roux, "Generalized MPLS (GMPLS) Protocol
             Extensions for Multi-Layer and Multi-Region Networks (MLN/
             MRN)", RFC 6001, DOI 10.17487/RFC6001, October 2010,
             <http://www.rfc-editor.org/info/rfc6001>.

  [RFC6060]  Fedyk, D., Shah, H., Bitar, N., and A. Takacs,
             "Generalized Multiprotocol Label Switching (GMPLS) Control
             of Ethernet Provider Backbone Traffic Engineering (PBB-
             TE)", RFC 6060, DOI 10.17487/RFC6060, March 2011,
             <http://www.rfc-editor.org/info/rfc6060>.

  [RFC6511]  Ali, Z., Swallow, G., and R. Aggarwal, "Non-Penultimate
             Hop Popping Behavior and Out-of-Band Mapping for RSVP-TE
             Label Switched Paths", RFC 6511, DOI 10.17487/RFC6511,
             February 2012, <http://www.rfc-editor.org/info/rfc6511>.

  [RFC6790]  Kompella, K., Drake, J., Amante, S., Henderickx, W., and
             L. Yong, "The Use of Entropy Labels in MPLS Forwarding",
             RFC 6790, DOI 10.17487/RFC6790, November 2012,
             <http://www.rfc-editor.org/info/rfc6790>.

  [RFC7260]  Takacs, A., Fedyk, D., and J. He, "GMPLS RSVP-TE
             Extensions for Operations, Administration, and Maintenance
             (OAM) Configuration", RFC 7260, DOI 10.17487/RFC7260, June
             2014, <http://www.rfc-editor.org/info/rfc7260>.

6.2.  Informative References

  [OBJ-FUN]  Ali, Z., Swallow, G., Filsfils, C., Fang, L., Kumaki, K.,
             Kunze, R., Ceccarelli, D., and X. Zhang, "Resource
             ReserVation Protocol-Traffic Engineering (RSVP-TE)
             Extension for Signaling Objective Function and Metric
             Bound", Work in Progress, draft-ali-ccamp-rc-objective-
             function-metric-bound-05, February 2014.





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  [RFC4990]  Shiomoto, K., Papneja, R., and R. Rabbat, "Use of
             Addresses in Generalized Multiprotocol Label Switching
             (GMPLS) Networks", RFC 4990, DOI 10.17487/RFC4990,
             September 2007, <http://www.rfc-editor.org/info/rfc4990>.

  [RFC6163]  Lee, Y., Ed., Bernstein, G., Ed., and W. Imajuku,
             "Framework for GMPLS and Path Computation Element (PCE)
             Control of Wavelength Switched Optical Networks (WSONs)",
             RFC 6163, DOI 10.17487/RFC6163, April 2011,
             <http://www.rfc-editor.org/info/rfc6163>.

  [RFC7571]  Dong, J., Chen, M., Li, Z., and D. Ceccarelli, "GMPLS
             RSVP-TE Extensions for Lock Instruct and Loopback", RFC
             7571, DOI 10.17487/RFC7571, July 2015,
             <http://www.rfc-editor.org/info/rfc7571>.

  [RSVP-TE-HOPS]
             Kern, A. and A. Takacs, "Encoding of Attributes of LSP
             intermediate hops using RSVP-TE", Work in Progress,
             draft-kern-ccamp-rsvpte-hop-attributes-00, October 2009.

  [SRLG-COLLECT]
             Zhang, F., Dios, O., Li, D., Margaria, C., Hartley, M.,
             and Z. Ali, "RSVP-TE Extensions for Collecting SRLG
             Information", Work in Progress, draft-ietf-teas-rsvp-te-
             srlg-collect-00, December 2014.

  [WSON-SIG]
             Bernstein, G., Xu, S., Lee, Y., Martinelli, G., and H.
             Harai, "Signaling Extensions for Wavelength Switched
             Optical Networks", Work in Progress, draft-ietf-ccamp-
             wson-signaling-10, March 2015.

Acknowledgments

  The authors would like to thank Lou Berger for his directions and
  Attila Takacs for inspiring [RSVP-TE-HOPS].  The authors also thank
  Dirk Schroetter for his contribution to the initial draft versions of
  this document.












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Authors' Addresses

  Cyril Margaria (editor)
  Juniper
  200 Somerset Corporate Boulevard, Suite 4001
  Bridgewater, NJ  08807
  United States

  Email: [email protected]


  Giovanni Martinelli
  Cisco
  via Philips 12
  Monza  20900
  Italy

  Phone: +39 039 209 2044
  Email: [email protected]


  Steve Balls
  Metaswitch
  100 Church Street
  Enfield  EN2 6BQ
  United Kingdom

  Phone: +44 208 366 1177
  Email: [email protected]


  Ben Wright
  Metaswitch
  100 Church Street
  Enfield  EN2 6BQ
  United Kingdom

  Phone: +44 208 366 1177
  Email: [email protected]












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