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Versions: 00 01 02

MPLS Working Group                                          H. Sitaraman
Internet-Draft                                                 V. Beeram
Intended status: Standards Track                        Juniper Networks
Expires: September 11, 2017                                    T. Parikh
                                                                 Verizon
                                                          March 10, 2017


      Signaling RSVP-TE tunnels on a shared MPLS forwarding plane
             draft-sitaraman-mpls-rsvp-shared-labels-00.txt

Abstract

   As the scale of MPLS RSVP-TE LSPs has grown, various implementation
   recommendations have been proposed to manage control plane state.
   However, the forwarding plane footprint of labels at a transit LSR
   has remained proportional to the total LSP state in the control
   plane.  This draft defines a mechanism to prevent the label space
   limit on an LSR from being a constraint to control plane scaling on
   that node.  It introduces the notion of pre-installed per TE link
   'pop labels' that are shared by MPLS RSVP-TE LSPs that traverse these
   links and thus significantly reducing the forwarding plane state
   required.  This couples the feature benefits of the RSVP-TE control
   plane with the simplicity of the Segment Routing MPLS forwarding
   plane.  This document also introduces the ability to mix different
   types of label operations along the path of the LSP, thereby allowing
   the ingress or an external controller to influence how to optimally
   place a LSP.

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
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on September 11, 2017.






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Copyright Notice

   Copyright (c) 2017 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
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   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
   2.  Conventions used in this document . . . . . . . . . . . . . .   4
   3.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   4
   4.  Allocation of pop labels  . . . . . . . . . . . . . . . . . .   4
   5.  RSVP-TE pop and forward tunnel setup  . . . . . . . . . . . .   4
   6.  Mixing pop and swap labels in a RSVP-TE tunnel  . . . . . . .   6
   7.  Distributing label stack imposition . . . . . . . . . . . . .   7
   8.  Facility backup protection  . . . . . . . . . . . . . . . . .   7
     8.1.  Link Protection . . . . . . . . . . . . . . . . . . . . .   7
     8.2.  Node Protection . . . . . . . . . . . . . . . . . . . . .   8
   9.  Quantifying pop labels  . . . . . . . . . . . . . . . . . . .   8
   10. Protocol Extensions . . . . . . . . . . . . . . . . . . . . .   9
     10.1.  Requirements . . . . . . . . . . . . . . . . . . . . . .   9
     10.2.  Attributes Flags TLV: Pop Label  . . . . . . . . . . . .   9
     10.3.  RRO Label Subobject Flag: Pop Label  . . . . . . . . . .  10
     10.4.  Attributes TLV: Label Stack Imposition TLV . . . . . . .  10
   11. OAM considerations  . . . . . . . . . . . . . . . . . . . . .  11
   12. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  11
   13. Contributors  . . . . . . . . . . . . . . . . . . . . . . . .  11
   14. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  11
     14.1.  Attribute Flags: Pop Label . . . . . . . . . . . . . . .  11
     14.2.  Attribute TLV: Label Stack Imposition TLV  . . . . . . .  11
     14.3.  Record Route Label Sub-object Flags: Pop Label . . . . .  12
   15. Security Considerations . . . . . . . . . . . . . . . . . . .  12
   16. References  . . . . . . . . . . . . . . . . . . . . . . . . .  12
     16.1.  Normative References . . . . . . . . . . . . . . . . . .  12
     16.2.  Informative References . . . . . . . . . . . . . . . . .  13
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14






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1.  Introduction

   Various RSVP-TE scaling recommendations [RFC2961]
   [I-D.ietf-teas-rsvp-te-scaling-rec] have been proposed for
   implementations to adopt guidelines that would allow the RSVP-TE
   [RFC3209] control plane to scale better.  The forwarding plane state
   required to handle the equivalent control plane state remains
   unchanged and is proportional to the total LSP state in the control
   plane.  The motivation of this draft is to prevent the platform
   specific label space limit on an LSR from being a constraint to
   pushing the limits of control plane scaling on that node.

   This document proposes the allocation of a 'pop label' by a LSR for
   each of its TE links.  The label is installed in the MPLS forwarding
   plane with a pop label operation and to forward the received packet
   over the TE link.  This label is sent normally by the LSR in the
   Label object in the Resv message as LSPs are setup.  The ingress LER
   SHOULD construct and push a stack of labels [RFC3031] as received in
   the Record Route object(RRO) in the Resv message.

   This pop and forward data plane behavior is similar to that used by
   Segment Routing (SR) [I-D.ietf-spring-segment-routing] using a MPLS
   forwarding plane and a series of adjacency segments.  The RSVP-TE pop
   and forward tunnels can co-exist with SR LSPs as described in
   [I-D.sitaraman-sr-rsvp-coexistence-rec].

   RSVP-TE using a pop and forward data plane offers the following
   benefits:

   1.  Shared forwarding plane: The transit label on a TE link is shared
       among RSVP-TE tunnels traversing the link and is used independent
       of the ingress and egress of the LSPs.

   2.  Faster LSP setup time: The forwarding plane state is not
       programmed during LSP setup and teardown resulting in faster LSP
       setup time.

   3.  Hitless routes: New transit labels are not required on complete
       path overlap during make-before-break (MBB) resulting in a faster
       MBB event.  This avoids the ingress LER and the services that
       might be using the tunnel from needing to update its forwarding
       plane with new tunnel labels.  Periodic MBB events are relatively
       common in networks that deploy auto-bandwidth on RSVP-TE LSPs to
       monitor bandwidth utilization and periodically adjust LSP
       bandwidth.

   4.  Mix and match labels: Both 'pop' and 'swap' labels can be mixed
       across transit hops for a single RSVP-TE tunnel (see Section 6).



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       This allows local policy at an ingress or path computation engine
       to influence RSVP-TE to mix and match different types of labels
       across a LSP path.

   No additional extensions are required to IGP-TE in order to support
   this pop and forward data plane.  Functionalities such as bandwidth
   admission control, LSP priorities, preemption, auto-bandwidth and
   Fast Reroute continue to work with this forwarding plane.

2.  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].

3.  Terminology

   Pop label: An incoming label at a LSR that will be popped and
   forwarded over a specific TE link to a neighbor.

   Swap label: An incoming label at a LSR that will be swapped to an
   outgoing label and forwarded over a specific downstream TE link.

   Pop and forward data plane: A forwarding plane where every LSR along
   the path uses a pop label.

   RSVP-TE pop and forward tunnel: A MPLS RSVP-TE tunnel that uses a pop
   and forward data plane.

4.  Allocation of pop labels

   A LSR SHOULD allocate a unique pop label for each TE link.  The
   forwarding action for the pop label should it appear on top of the
   label stack MUST be to pop the label and forward the packet over the
   TE link to the downstream neighbor of the RSVP-TE tunnel.  Multiple
   labels MAY be allocated for the TE link to accommodate tunnels
   requesting no protection, link-protection and node-protection over
   the specific TE link.

5.  RSVP-TE pop and forward tunnel setup

   This section provides an example of how the RSVP-TE signaling
   procedure works to setup a tunnel utilizing a pop and forward data
   plane.  The sample topology below will be used to explain the setup.







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        Labels shown at each node are pop labels for that neighbor

    +---+100  +---+150  +---+200  +---+250  +---+
    | A |-----| B |-----| C |-----| D |-----| E |
    +---+     +---+     +---+     +---+     +---+
      |110      |450      |550      |650      |850
      |         |         |         |         |
      |         |400      |500      |600      |800
      |       +---+     +---+     +---+     +---+
      +-------| F |-----|G  |-----|H  |-----|I  |
              +---+300  +---+350  +---+700  +---+

                 Figure 1: Pop and forward label topology

   RSVP-TE tunnel T1: From A to E on path A-B-C-D-E
   RSVP-TE tunnel T2: From F to E on path F-B-C-D-E

   Both tunnels share the TE links B-C, C-D and D-E.

   As RSVP-TE signals the setup (using the pop label attributes flag
   defined in Section 10.2) of tunnel T1, when LSR D receives the Resv
   message from the egress E, it checks the next-hop TE link (D-E) and
   provides the pop label (250) in the Resv message for the tunnel.  The
   label is sent in the Label object and is also recorded in the Label
   sub-object (using the pop label bit defined in Section 10.3) carried
   in the RRO.  Similarly, C provides the pop label (200) for the next-
   hop TE link C-D and B provides the pop label (150) for the next-hop
   TE link B-C.  For the tunnel T2, the transit LSRs provide the same
   pop labels as described for tunnel T1.

   Both LER A and F will push the same stack of labels {150(top), 200,
   250} for tunnels T1 and T2 respectively.  It should be noted that a
   transit LSR does not use the pop label provided in the label object
   by its downstream LSR in the NHLFE as the outgoing label.  The
   recorded labels in the RRO are of interest to the ingress LER in
   order to construct a stack of labels.

   If there were another RSVP-TE tunnel T3 from F to I on path
   F-B-C-D-E-I, then this would also share the TE links B-C, C-D and D-E
   and additionally traverse link E-I.  The label stack used by F would
   be {150(top), 200, 250, 850}. Hence, regardless of the ingress and
   egress LERs from where the LSPs start and end, they will share LSR
   labels at shared hops in the pop and forward data plane.

   There MAY be local operator policy at the ingress LER that influences
   the maximum depth of the label stack that can be pushed for a RSVP-TE
   pop and forward tunnel.  Prior to signaling the LSP, if the ingress
   LER decides that it would be unable to push the entire label stack



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   should every transit hop provide a pop label, then the LER can choose
   to either not signal a RSVP-TE pop and forward tunnel or can adopt
   techniques mentioned in Section 6 or Section 7.

6.  Mixing pop and swap labels in a RSVP-TE tunnel

   Labels can be mixed across transit hops in a single MPLS RSVP-TE LSP.
   Certain LSRs can use pop labels and others can use swap labels.  The
   ingress can construct a label stack appropriately based on what type
   of label is recorded from every transit LSR.

    Labels shown at each node are pop labels for that TE link. (#) are
                               swap labels.

                             (#)       (#)
    +---+100  +---+150  +---+200  +---+250  +---+
    | A |-----| B |-----| C |-----| D |-----| E |
    +---+     +---+     +---+     +---+     +---+
      |110      |450      |550      |650      |850
      |         |         |         |         |
      |         |400      |500      |600      |800
      |       +---+     +---+     +---+     +---+
      +-------| F |-----|G  |-----|H  |-----|I  |
              +---+300  +---+350  +---+700  +---+

                 Figure 2: Mix pop and swap label topology

   If the transit LSR is allocating a swap label to be sent upstream in
   the Resv, then the label operation in the NHLFE MUST be a swap to any
   label received from the downstream LSR.  If the transit LSR is using
   a pop label to be sent upstream in the Resv, then the label operation
   in the NHLFE MUST be a pop and forward regardless of any label
   received from the downstream LSR.

   The ingress LER MUST check the type of label received from each
   transit hop as recorded in the RRO in the Resv message and generate
   the appropriate label stack to use for the RSVP-TE tunnel.

   The following logic could be used by the ingress LER while
   constructing the label stack:

   Each RRO label sub-object SHOULD be processed starting with the label
   sub-object from the first downstream hop.  Any label provided by the
   first downstream hop MUST always be pushed on the label stack
   regardless of the label type.  If the label type is a pop label, then
   any label from the next downstream hop MUST also be pushed on the
   constructed label stack.  If the label type is a swap label, then any
   label from the next downstream hop MUST NOT be pushed on the



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   constructed label stack.  For example, the LSP from A to I using path
   A-B-C-D-E-I will use a label stack of {150(top), 200}.

   Signaling extensions for the ingress LER to request a certain type of
   label from a particular hop is defined in Section 10.2.  A Hop-Count
   value of 1 (Label Stack Imposition Attribute) SHOULD be used for the
   specific hops to allocate a swap label.

7.  Distributing label stack imposition

   One or more transit LSRs can assist the ingress LER by imposing part
   of the label stack required for the path.  From Figure 1, ingress LER
   A can use the assistance of transit LSRs to push labels downstream of
   that LSR.  For example, LER A can push label 150 and LSR C can push
   {200(top), 250} for the LSP taking path A-B-C-D-E.

   The ingress LER can request one or more specific transit hops to
   handle pushing labels for N of its downstream hops.  To achieve this
   request properly, the ingress can learn the label stack depth push
   limit of the transit LSRs.  The mechanism by which the ingress or
   controller (hosting the path computation element) learns this
   information is outside the scope of this document.  The particular
   transit hops SHOULD allocate a swap label that will result in that
   label being replaced and a set of labels pushed to accommodate N
   downstream hops.

   Signaling extensions for the ingress LER to request one or more
   transit LSRs to handle label stack imposition for N downstream hops
   or for the transit hop to indicate to the ingress that it can handle
   label stack imposition for N downstream hops is defined in
   Section 10.2.  The Hop-Count field (Label Stack Imposition Attribute)
   can be used to indicate the value of N.


8.  Facility backup protection

   The following section describe how link and node protection works
   with facility backup protection [RFC4090] for the RSVP-TE pop and
   forward tunnels.

8.1.  Link Protection

   To provide link protection at a PLR with a pop and forward data
   plane, the LSR SHOULD allocate a separate pop label for the TE link
   that will be used for RSVP-TE tunnels that request link-protection
   from the ingress.  No signaling extensions are required to support
   link protection for RSVP-TE tunnels over the pop and forward data
   plane.



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       (*) are pop labels to offer link protection for that TE link


         101(*)    151(*)    201(*)    251(*)
    +---+100  +---+150  +---+200  +---+250  +---+
    | A |-----| B |-----| C |-----| D |-----| E |
    +---+     +---+     +---+     +---+     +---+
      |110      |450      |550      |650      |850
      |         |         |         |         |
      |         |400      |500      |600      |800
      |       +---+     +---+     +---+     +---+
      +-------| F |-----|G  |-----|H  |-----|I  |
              +---+300  +---+350  +---+700  +---+

                    Figure 3: Link protection topology

   At each LSR, link protected pop labels can be allocated for each TE
   link and a link protecting facility backup LSP can be created to
   protect the TE link.  This label can be sent by the LSR for LSPs
   requesting link-protection over the specific TE link.  Since the
   facility backup terminates at the next-hop (merge point), the
   incoming label on the packet will be what the merge point expects.

   As an example, LSR B can install a facility backup LSP for the link
   protected pop label 151.  When the TE link B-C is up, LSR B will pop
   151 and send the packet to C.  If the TE link B-C is down, the LSR
   can pop 151 and send the packet via the facility backup to C.

8.2.  Node Protection

   The solutions for the PLR to provide node-protection for the pop and
   forward RSVP-TE tunnel will be explained in the next version of the
   document.

9.  Quantifying pop labels

   This section attempts to quantify the number of labels required in
   the forwarding plane to provide sharing of labels across RSVP-TE pop
   and forward tunnels.  A MPLS RSVP-TE tunnel offers either no
   protection, link protection or node protection and only one of these
   labels is required per tunnel during signaling.  The scale of the
   number of pop labels required per LSR can be deduced as follows:


   o  For a LSR having X neighbors reachable across Y interfaces, the
      number of unprotected pop labels = X





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   o  For a PLR having X neighbors reachable across Y interfaces, number
      of link protected pop labels = X

   o  For a PLR having X neighbors, each having Nx neighbors (i.e. next-
      nexthop for PLR), number of node protected pop labels =
      SUM_OF_ALL(Nx)

   Total number of pop labels = Unprotected pop labels + link protected
   pop labels + node protected pop labels = 2X + SUM(Nm)

10.  Protocol Extensions

10.1.  Requirements

   The functionality discussed in this document imposes the following
   requirements on the signaling protocol.


   o  The Ingress of the LSP SHOULD have the ability to mandate/request
      the use and recording of pop labels at all hops along the path of
      the LSP.

   o  When the use of pop labels is mandated/requested for the entire
      path,

       the node recording the pop label SHOULD have the ability to
       indicate if the recorded label is a pop label.

       the ingress SHOULD have the ability to override this path
       specific behavior by

           explicitly mandating specific hops to not use pop labels (or)

           mandating specific hops to share the onus of imposing the
           label stack (and also specifying the desired number of hops
           that need to be accounted for at that node)

       the node which was mandated to share the onus of imposing the
       label stack SHOULD have the ability to indicate the actual number
       of hops that it can account for.

10.2.  Attributes Flags TLV: Pop Label

   Bit Number (TBD1): Pop Label

   The presence of this in the LSP_ATTRIBUTES/LSP_REQUIRED_ATTRIBUTES
   object of a Path message indicates that the ingress has requested/
   mandated the use and recording of pop labels at all hops along the



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   path of this LSP.  When a node that does not cater to the request/
   mandate receives a Path message carrying the LSP_REQUIRED_ATTRIBUTES
   object with this flag set, it MUST send a PathErr message with an
   error code of 'routing problem' and an error value of 'pop label
   usage failure'.

10.3.  RRO Label Subobject Flag: Pop Label

   Bit Number (TBD2): Pop Label

   The presence of this flag indicates that the recorded label is a pop
   label.  This flag SHOULD be used by a node only if the use and
   recording of pop labels is requested/mandated for this LSP.

10.4.  Attributes TLV: Label Stack Imposition TLV

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Reserved                              |   Hop-Count   |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Attribute TLV Type: TBD3

   The presence of this in the HOP_ATTRIBUTES subobject [RFC7570] of an
   ERO object in the Path message mandates the hop identified by the
   preceding IPv4 or IPv6 or Unnumbered Interface ID subobject to share
   the onus of imposing the label stack.  This attribute MUST be used
   only if the use and recording of pop labels is requested/mandated for
   this LSP (only if Pop Label flag is present in the LSP_ATTRIBUTES/
   LSP_REQUIRED_ATTRIBUTES object).  If the node is not able to comply
   with this mandate, it MUST send a PathErr message with an error code
   of 'routing problem' and an error value of 'label stack imposition
   failure'.

   The Hop-Count field specifies the desired number of hops that this
   node needs to account for.  A Hop-Count value of 0 is considered
   invalid and a value of 1 implies that this hop perform a normal swap
   or pop (if this hop is PHP) operation towards the next downstream
   hop.

   The presence of this in the HOP_ATTRIBUTES subobject of an RRO object
   in the RESV message indicates that the hop identified by the
   preceding IPv4 or IPv6 or Unnumbered Interface ID subobject is
   sharing the onus of imposing the label stack.  The Hop-Count field
   specifies the actual number of hops that this node can account for.
   This should not be included in the RESV message unless this TLV is
   also present in the corresponding Path message for this hop.



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11.  OAM considerations

   Any extensions necessary for MPLS LSP traceroute for the RSVP-TE pop
   and forward tunnel will be explained in the next version of the
   document.

12.  Acknowledgements

   The authors would like to thank Adrian Farrel, Kireeti Kompella,
   Markus Jork and Ross Callon for their input from discussions.

13.  Contributors

   The following individuals contributed to this document:

   Raveendra Torvi
   Juniper Networks
   Email: rtorvi@juniper.net

   Chandra Ramachandran
   Juniper Networks
   Email: csekar@juniper.net

14.  IANA Considerations

14.1.  Attribute Flags: Pop Label

   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.  This document introduces a new Attribute Flag.

      Bit  Name                Attribute Attribute RRO ERO Reference
      No.                      FlagsPath FlagsResv
      TBD1 Pop Label           Yes       No        No  No  This document
                                                           (Section 5)

14.2.  Attribute TLV: Label Stack Imposition TLV

   IANA manages the "Attribute TLV Space" registry as part of the
   'Resource Reservation Protocol-Traffic Engineering (RSVP-TE)
   Parameters' registry located at http://www.iana.org/assignments/rsvp-
   te-parameters.  This document introduces a new Attribute TLV.








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      Type   Name     Allowed on  Allowed on   Allowed on  Reference
                      LSP         LSP REQUIRED LSP Hop
                      ATTRIBUTES  ATTRIBUTES   Attributes


      TBD3  Label     No          No           Yes         This document
            Stack                                          (Section 7)
            Imposition
            TLV

14.3.  Record Route Label Sub-object Flags: Pop Label

   IANA manages the 'Record Route Object Sub-object 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.  This registry currently does not include Label
   Sub-object Flags.  This document proposes the addition of a new sub-
   registry for Label Sub-object Flags as shown below.

      Flag  Name                    Reference

      0x1   Global Label            RFC 3209
      TBD2  Pop Label               This document (Section 5)


15.  Security Considerations

   This document does not introduce new security issues.  The security
   considerations pertaining to the original RSVP protocol [RFC2205] and
   RSVP-TE [RFC3209] and those that are described in [RFC5920] remain
   relevant.

16.  References

16.1.  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>.






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   [RFC3031]  Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol
              Label Switching Architecture", RFC 3031,
              DOI 10.17487/RFC3031, January 2001,
              <http://www.rfc-editor.org/info/rfc3031>.

   [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>.

   [RFC4090]  Pan, P., Ed., Swallow, G., Ed., and A. Atlas, Ed., "Fast
              Reroute Extensions to RSVP-TE for LSP Tunnels", RFC 4090,
              DOI 10.17487/RFC4090, May 2005,
              <http://www.rfc-editor.org/info/rfc4090>.

   [RFC7570]  Margaria, C., Ed., Martinelli, G., Balls, S., and B.
              Wright, "Label Switched Path (LSP) Attribute in the
              Explicit Route Object (ERO)", RFC 7570,
              DOI 10.17487/RFC7570, July 2015,
              <http://www.rfc-editor.org/info/rfc7570>.

16.2.  Informative References

   [I-D.ietf-spring-segment-routing]
              Filsfils, C., Previdi, S., Decraene, B., Litkowski, S.,
              and R. Shakir, "Segment Routing Architecture", draft-ietf-
              spring-segment-routing-11 (work in progress), February
              2017.

   [I-D.ietf-teas-rsvp-te-scaling-rec]
              Beeram, V., Minei, I., Shakir, R., Pacella, D., and T.
              Saad, "Implementation Recommendations to Improve the
              Scalability of RSVP-TE Deployments", draft-ietf-teas-rsvp-
              te-scaling-rec-03 (work in progress), October 2016.

   [I-D.sitaraman-sr-rsvp-coexistence-rec]
              Sitaraman, H., Beeram, V., Minei, I., and S. Sivabalan,
              "Recommendations for RSVP-TE and Segment Routing LSP co-
              existence", draft-sitaraman-sr-rsvp-coexistence-rec-02
              (work in progress), February 2017.

   [RFC2961]  Berger, L., Gan, D., Swallow, G., Pan, P., Tommasi, F.,
              and S. Molendini, "RSVP Refresh Overhead Reduction
              Extensions", RFC 2961, DOI 10.17487/RFC2961, April 2001,
              <http://www.rfc-editor.org/info/rfc2961>.






Sitaraman, et al.      Expires September 11, 2017              [Page 13]


Internet-Draft       RSVP-TE pop and forward tunnel           March 2017


   [RFC5920]  Fang, L., Ed., "Security Framework for MPLS and GMPLS
              Networks", RFC 5920, DOI 10.17487/RFC5920, July 2010,
              <http://www.rfc-editor.org/info/rfc5920>.

Authors' Addresses

   Harish Sitaraman
   Juniper Networks
   1133 Innovation Way
   Sunnyvale, CA  94089
   US

   Email: hsitaraman@juniper.net


   Vishnu Pavan Beeram
   Juniper Networks
   10 Technology Park Drive
   Westford, MA  01886
   US

   Email: vbeeram@juniper.net


   Tejal Parikh
   Verizon
   400 International Parkway
   Richardson, TX  75081
   US

   Email: tejal.parikh@verizon.com




















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