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Versions: 00 01 02 03 draft-ietf-spring-segment-routing-ldp-interop

Network Working Group                                   C. Filsfils, Ed.
Internet-Draft                                           S. Previdi, Ed.
Intended status: Standards Track                             A. Bashandy
Expires: September 10, 2015                          Cisco Systems, Inc.
                                                             B. Decraene
                                                            S. Litkowski
                                                                  Orange
                                                            M. Horneffer
                                                        Deutsche Telekom
                                                            I. Milojevic
                                                          Telekom Srbija
                                                               R. Shakir
                                                         British Telecom
                                                                 S. Ytti
                                                                  TDC Oy
                                                           W. Henderickx
                                                          Alcatel-Lucent
                                                             J. Tantsura
                                                                Ericsson
                                                               E. Crabbe
                                                  Individual Contributor
                                                           March 9, 2015


               Segment Routing interoperability with LDP
          draft-filsfils-spring-segment-routing-ldp-interop-03

Abstract

   A Segment Routing (SR) node steers a packet through a controlled set
   of instructions, called segments, by prepending the packet with an SR
   header.  A segment can represent any instruction, topological or
   service-based.  SR allows to enforce a flow through any topological
   path and service chain while maintaining per-flow state only at the
   ingress node to the SR domain.

   The Segment Routing architecture can be directly applied to the MPLS
   data plane with no change in the forwarding plane.  This drafts
   describes how Segment Routing operates in a network where LDP is
   deployed and in the case where SR-capable and non-SR-capable nodes
   coexist.

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].




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Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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   This Internet-Draft will expire on September 10, 2015.

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
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   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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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.  SR/LDP Ship-in-the-night coexistence  . . . . . . . . . . . .   3
     2.1.  MPLS2MPLS co-existence  . . . . . . . . . . . . . . . . .   5
     2.2.  IP2MPLS co-existence  . . . . . . . . . . . . . . . . . .   6
   3.  Migration from LDP to SR  . . . . . . . . . . . . . . . . . .   6
   4.  SR and LDP Interworking . . . . . . . . . . . . . . . . . . .   7
     4.1.  LDP to SR . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.2.  SR to LDP . . . . . . . . . . . . . . . . . . . . . . . .   8
   5.  Leveraging SR benefits for LDP-based traffic  . . . . . . . .   9
     5.1.  Eliminating Directed LDP Session  . . . . . . . . . . . .  11
     5.2.  Guaranteed FRR coverage . . . . . . . . . . . . . . . . .  12
   6.  Inter-AS Option C, Carrier's Carrier and Seamless MPLS  . . .  13
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  13
   8.  Manageability Considerations  . . . . . . . . . . . . . . . .  13



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   9.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   10. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  13
   11. References  . . . . . . . . . . . . . . . . . . . . . . . . .  14
     11.1.  Normative References . . . . . . . . . . . . . . . . . .  14
     11.2.  Informative References . . . . . . . . . . . . . . . . .  14
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  14

1.  Introduction

   Segment Routing, as described in [I-D.ietf-spring-segment-routing],
   can be used on top of the MPLS data plane without any modification as
   described in [I-D.ietf-spring-segment-routing-mpls].

   Segment Routing control plane can co-exist with current label
   distribution protocols such as LDP.

   This draft outlines the mechanisms through which SR provides
   interoperability with LDP in cases where a mix of SR-capable and non-
   SR-capable routers co-exist within the same network.

   The first section describes the co-existence of SR with other MPLS
   Control Plane.  The second section documents a method to migrate from
   LDP to SR-based MPLS tunneling.  The third section documents the
   interworking of LDP and SR in the case of non-homogenous deployment.
   The fourth section describes how a partial SR deployment can be used
   to provide SR benefits to LDP-based traffic.  The fifth section
   describes a possible application of SR in the context of inter-domain
   MPLS use-cases.

2.  SR/LDP Ship-in-the-night coexistence

   We call "MPLS Control Plane Client (MCC)" any control plane protocol
   installing forwarding entries in the MPLS data plane.  SR, LDP, RSVP-
   TE, BGP 3107, VPNv4, etc. are examples of MCCs.

   An MCC, operating at node N, must ensure that the incoming label it
   installs in the MPLS data plane of Node N has been uniquely allocated
   to himself.

   Thanks to the defined segment allocation rule and specifically the
   notion of the SRGB, SR can co-exist with any other MCC.

   This is clearly the case for the adjacency segment: it is a local
   label allocated by the label manager, as for any MCC.

   This is clearly the case for the prefix segment: the label manager
   allocates the SRGB set of labels to the SR MCC client and the




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   operator ensures the unique allocation of each global prefix segment/
   label within the allocated SRGB set.

   Note that this static label allocation capability of the label
   manager has been existing for many years across several vendors and
   hence is not new.  Furthermore, note that the label-manager ability
   to statically allocate a range of labels to a specific application is
   not new either.  This is required for MPLS-TP operation.  In this
   case, the range is reserved by the label manager and it is the MPLS-
   TP NMS (acting as an MCC) that ensures the unique allocation of any
   label within the allocated range and the creation of the related MPLS
   forwarding entry.

   Let us illustrate an example of ship-in-the-night (SIN) coexistence.

       PE2          PE4
         \          /
   PE1----A----B---C---PE3

                         Figure 1: SIN coexistence

   The EVEN VPN service is supported by PE2 and PE4 while the ODD VPN
   service is supported by PE1 and PE3.  The operator wants to tunnel
   the ODD service via LDP and the EVEN service via SR.

   This can be achieved in the following manner:

      The operator configures PE1, PE2, PE3, PE4 with respective
      loopbacks 192.0.2.201/32, 192.0.2.202/32, 192.0.2.203/32,
      192.0.2.204/32.  These PE's advertised their VPN routes with next-
      hop set on their respective loopback address.

      The operator configures A, B, C with respective loopbacks
      192.0.2.1/32, 192.0.2.2/32, 192.0.2.3/32.

      The operator configures PE2, A, B, C and PE4 with SRGB [100, 300].

      The operator attaches the respective Node-SIDs 202, 101, 102, 103
      and 204 to the loopbacks of nodes PE2, A, B, C and PE4.  The Node-
      SID's are configured to request penultimate-hop-popping.

      PE1, A, B, C and PE3 are LDP capable.

      PE1 and PE3 are not SR capable.

   PE3 sends an ODD VPN route to PE1 with next-hop 192.0.2.203 and VPN
   label 10001.




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   From an LDP viewpoint: PE1 received an LDP label binding (1037) for
   FEC 192.0.2.203/32 from its nhop A.  A received an LDP label binding
   (2048) for that FEC from its nhop B.  B received an LDP label binding
   (3059) for that FEC from its nhop C.  C received implicit-null LDP
   binding from its next-hop PE3.

   As a result, PE1 sends its traffic to the ODD service route
   advertised by PE3 to next-hop A with two labels: the top label is
   1037 and the bottom label is 10001.  A swaps 1037 with 2048 and
   forwards to B.  B swaps 2048 with 3059 and forwards to C.  C pops
   3059 and forwards to PE3.

   PE4 sends an EVEN VPN route to PE2 with next-hop 192.0.2.204 and VPN
   label 10002.

   From an SR viewpoint: PE1 maps the IGP route 192.0.2.204/32 onto
   Node-SID 204; A swaps 204 with 204 and forwards to B; B swaps 204
   with 204 and forwards to C; C pops 204 and forwards to PE4.

   As a result, PE2 sends its traffic to the VPN service route
   advertised by PE4 to next-hop A with two labels: the top label is 204
   and the bottom label is 10002.  A swaps 204 with 204 and forwards to
   B.  B swaps 204 with 204 and forwards to C.  C pops 204 and forwards
   to PE4.

   The two modes of MPLS tunneling co-exist.

      The ODD service is tunneled from PE1 to PE3 through a continuous
      LDP LSP traversing A, B and C.

      The EVEN service is tunneled from PE2 to PE4 through a continuous
      SR node segment traversing A, B and C.

2.1.  MPLS2MPLS co-existence

   We want to highlight that several MPLS2MPLS entries can be installed
   in the data plane for the same prefix.

   Let us examine A's MPLS forwarding table as an example:

      Incoming label: 1037

          - outgoing label: 2048
          - outgoing nhop: B
          - Note: this entry is programmed by LDP for 192.0.2.203/32

      Incoming label: 203




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          - outgoing label: 203
          - outgoing nhop: B
          - Note: this entry is programmed by SR for 192.0.2.203/32

   These two entries can co-exist because their incoming label is
   unique.  The uniqueness is guaranteed by the label manager allocation
   rules.

   The same applies for the MPLS2IP forwarding entries.

2.2.  IP2MPLS co-existence

   By default, we propose that if both LDP and SR propose an IP2MPLS
   entry for the same IP prefix, then the LDP route is selected.

   A local policy on a router MUST allow to prefer the SR-provided
   IP2MPLS entry.

   Note that this policy may be locally defined.  There is no
   requirement that all routers use the same policy.

3.  Migration from LDP to SR

        PE2        PE4
          \        /
   PE1----P5--P6--P7---PE3

                            Figure 2: Migration

   Several migration techniques are possible.  We describe one technique
   inspired by the commonly used method to migrate from one IGP to
   another.

   T0: all the routers run LDP.  Any service is tunneled from an ingress
   PE to an egress PE over a continuous LDP LSP.

   T1: all the routers are upgraded to SR.  They are configured with the
   SRGB range [100, 300].  PE1, PE2, PE3, PE4, P5, P6 and P7 are
   respectively configured with the node segments 101, 102, 103, 104,
   105, 106 and 107 (attached to their service-recursing loopback).

      At this time, the service traffic is still tunneled over LDP LSP.
      For example, PE1 has an SR node segment to PE3 and an LDP LSP to
      PE3 but by default, as seen earlier, the LDP IP2MPLS encapsulation
      is preferred.

   T2: the operator enables the local policy at PE1 to prefer SR IP2MPLS
   encapsulation over LDP IP2MPLS.



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      The service from PE1 to any other PE is now riding over SR.  All
      other service traffic is still transported over LDP LSP.

   T3: gradually, the operator enables the preference for SR IP2MPLS
   encapsulation across all the edge routers.

      All the service traffic is now transported over SR.  LDP is still
      operational and services could be reverted to LDP.

      However, any traffic switched through LDP entries will still
      suffer from LDP-IGP synchronization.

   T4: LDP is unconfigured from all routers.

4.  SR and LDP Interworking

   In this section, we analyze a use-case where SR is available in one
   part of the network and LDP is available in another part.  We
   describe how a continuous MPLS tunnel can be built throughout the
   network.

        PE2            PE4
          \            /
   PE1----P5--P6--P7--P8---PE3

                     Figure 3: SR and LDP Interworking

   Let us analyze the following example:

      P6, P7, P8, PE4 and PE3 are LDP capable.

      PE1, PE2, P5 and P6 are SR capable.  PE1, PE2, P5 and P6 are
      configured with SRGB (100, 200) and respectively with node
      segments 101, 102, 105 and 106.

      A service flow must be tunneled from PE1 to PE3 over a continuous
      MPLS tunnel encapsulation.  We need SR and LDP to interwork.

4.1.  LDP to SR

   In this section, we analyze a right-to-left traffic flow.

   PE3 has learned a service route whose nhop is PE1.  PE3 has an LDP
   label binding from the nhop P8 for the FEC "PE1".  Hence PE3 sends
   its service packet to P8 as per classic LDP behavior.

   P8 has an LDP label binding from its nhop P7 for the FEC "PE1" and
   hence P8 forwards to P7 as per classic LDP behavior.



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   P7 has an LDP label binding from its nhop P6 for the FEC "PE1" and
   hence P7 forwards to P6 as per classic LDP behavior.

   P6 does not have an LDP binding from its nhop P5 for the FEC "PE1".
   However P6 has an SR node segment to the IGP route "PE1".  Hence, P6
   forwards the packet to P5 and swaps its local LDP-label for FEC "PE1"
   by the equivalent node segment (i.e. 101).

   P5 pops 101 (assuming PE1 advertised its node segment 101 with the
   penultimate-pop flag set) and forwards to PE1.

   PE1 receives the tunneled packet and processes the service label.

   The end-to-end MPLS tunnel is built from an LDP LSP from PE3 to P6
   and the related node segment from P6 to PE1.

4.2.  SR to LDP

   In this section, we analyze the left-to-right traffic flow.

   We assume that the operator configures P5 to act as a Segment Routing
   Mapping Server (SRMS) and advertise the following mappings: (P7,
   107), (P8, 108), (PE3, 103) and (PE4, 104).

   These mappings are advertised as Remote-Binding SID with Flag TBD.

   The mappings advertised by an SR mapping server result from local
   policy information configured by the operator.  If PE3 had been SR
   capable, the operator would have configured PE3 with node segment
   103.  Instead, as PE3 is not SR capable, the operator configures that
   policy at the SRMS and it is the latter which advertises the mapping.
   Multiple SRMS servers can be provisioned in a network for redundancy.

   The mapping server advertisements are only understood by the SR
   capable routers.  The SR capable routers install the related node
   segments in the MPLS data plane exactly like if the node segments had
   been advertised by the nodes themselves.

   For example, PE1 installs the node segment 103 with nhop P5 exactly
   as if PE3 had advertised node segment 103.

   PE1 has a service route whose nhop is PE3.  PE1 has a node segment
   for that IGP route: 103 with nhop P5.  Hence PE1 sends its service
   packet to P5 with two labels: the bottom label is the service label
   and the top label is 103.

   P5 swaps 103 for 103 and forwards to P6.




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   P6's next-hop for the IGP route "PE3" is not SR capable (P7 does not
   advertise the SR capability).  However, P6 has an LDP label binding
   from that next-hop for the same FEC (e.g.  LDP label 1037).  Hence,
   P6 swaps 103 for 1037 and forwards to P7.

   P7 swaps this label with the LDP-label received from P8 and forwards
   to P8.

   P8 pops the LDP label and forwards to PE3.

   PE3 receives the tunneled packet and processes the service label.

   The end-to-end MPLS tunnel is built from an SR node segment from PE1
   to P6 and an LDP LSP from P6 to PE3.

   Note: SR mappings advertisements cannot set Penultimate Hop Popping.
   In the previous example, P6 requires the presence of the segment 103
   such as to map it to the LDP label 1037.  For that reason, the P flag
   available in the Prefix-SID is not available in the Remote-Binding
   SID.

5.  Leveraging SR benefits for LDP-based traffic

   SR can be deployed such as to enhance LDP transport.  The SR
   deployment can be limited to the network region where the SR benefits
   are most desired.

   In Figure 4, let us assume:

      All link costs are 10 except FG which is 30.

      All routers are LDP capable.

      X, Y and Z are PE's participating to an important service S.

      The operator requires 50msec link-based FRR for service S.

      A, B, C, D, E, F and G are SR capable.

      X, Y, Z are not SR capable, e.g. as part of a staged migration
      from LDP to SR, the operator deploys SR first in a sub-part of the
      network and then everywhere.









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          X
          |
   Y--A---B---E--Z
      |   |    \
      D---C--F--G
              30

          Figure 4: Leveraging SR benefits for LDP-based-traffic

   The operator would like to resolve the following issues:

      To protect the link BA along the shortest-path of the important
      flow XY, B requires an RLFA repair tunnel to D and hence a
      directed LDP session from B to D.  The operator does not like
      these dynamically established multi-hop LDP sessions and would
      seek to eliminate them.

      There is no LFA/RLFA solution to protect the link BE along the
      shortest path of the important flow XZ.  The operator wants a
      guaranteed link-based FRR solution.

   The operator can meet these objectives by deploying SR only on A, B,
   C, D, E and F:

      The operator configures A, B, C, D, E, F and G with SRGB (100,
      200) and respective node segments 101, 102, 103, 104, 105, 106 and
      107.

      The operator configures D as an SR Mapping Server with the
      following policy mapping: (X, 201), (Y, 202), (Z, 203).

      Each SR node automatically advertises local adjacency segment for
      its IGP adjacencies.  Specifically, F advertises adjacency segment
      9001 for its adjacency FG.

   A, B, C, D, E, F and G keep their LDP capability and hence the flows
   XY and XZ are transported over end-to-end LDP LSP's.

   For example, LDP at B installs the following MPLS data plane entries:

   Incoming label: local LDB label bound by B for FEC Y
      Outgoing label: LDP label bound by A for FEC Y
      Outgoing nhop: A

   Incoming label: local LDB label bound by B for FEC Z
     Outgoing label: LDP label bound by E for FEC Z
     Outgoing nhop: E




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   The novelty comes from how the backup chains are computed for these
   LDP-based entries.  While LDP labels are used for the primary nhop
   and outgoing labels, SR information is used for the FRR construction.
   In steady state, the traffic is transported over LDP LSP.  In
   transient FRR state, the traffic is backup thanks to the SR enhanced
   capabilities.

   This helps meet the requirements of the operator:

      Eliminate directed LDP session.

      Guaranteed FRR coverage.

      Keep the traffic over LDP LSP in steady state.

      Partial SR deployment only where needed.

5.1.  Eliminating Directed LDP Session

   B's MPLS entry to Y becomes:

   - Incoming label: local LDB label bound by B for FEC Y
       Outgoing label: LDP label bound by A for FEC Y
       Backup outgoing label: SR node segment for Y {202}
       Outgoing nhop: A
       Backup nhop: repair tunnel: node segment to D {104}
        with outgoing nhop: C

   In steady-state, X sends its Y-destined traffic to B with a top label
   which is the LDP label bound by B for FEC Y.  B swaps that top label
   for the LDP label bound by A for FEC Y and forwards to A.  A pops the
   LDP label and forwards to Y.

   Upon failure of the link BA, B swaps the incoming top-label with the
   node segment for Y (202) and sends the packet onto a repair tunnel to
   D (node segment 104).  Thus, B sends the packet to C with the label
   stack {104, 202}. C pops the node segment 104 and forwards to D.  D
   swaps 202 for 202 and forwards to A.  A's nhop to Y is not SR capable
   and hence A swaps the incoming node segment 202 to the LDP label
   announced by its next-hop (in this case, implicit null).

   After IGP convergence, B's MPLS entry to Y will become:

   - Incoming label: local LDB label bound by B for FEC Y
       Outgoing label: LDP label bound by C for FEC Y
       Outgoing nhop: C

   And the traffic XY travels again over the LDP LSP.



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   Conclusion: the operator has eliminated its first problem: directed
   LDP sessions are no longer required and the steady-state traffic is
   still transported over LDP.  The SR deployment is confined to the
   area where these benefits are required.

5.2.  Guaranteed FRR coverage

   B's MPLS entry to Z becomes:

   - Incoming label: local LDB label bound by B for FEC Z
       Outgoing label: LDP label bound by E for FEC Z
       Backup outgoing label: SR node segment for Z {203}
       Outgoing nhop: E
       Backup nhop: repair tunnel to G: {106, 9001}

           G is reachable from B via the combination of a
           node segment to F {106} and an adjacency segment
           FG {9001}

           Note that {106, 107} would have equally work.
           Indeed, in many case, P's shortest path to Q is
           over the link PQ. The adjacency segment from P to
           Q is required only in very rare topologies where
           the shortest-path from P to Q is not via the link
           PQ.

   In steady-state, X sends its Z-destined traffic to B with a top label
   which is the LDP label bound by B for FEC Z.  B swaps that top label
   for the LDP label bound by E for FEC Z and forwards to E.  E pops the
   LDP label and forwards to Z.

   Upon failure of the link BE, B swaps the incoming top-label with the
   node segment for Z (203) and sends the packet onto a repair tunnel to
   G (node segment 106 followed by adjacency segment 9001).  Thus, B
   sends the packet to C with the label stack {106, 9001, 203}. C pops
   the node segment 106 and forwards to F.  F pops the adjacency segment
   9001 and forwards to G.  G swaps 203 for 203 and forwards to E.  E's
   nhop to Z is not SR capable and hence E swaps the incoming node
   segment 203 for the LDP label announced by its next-hop (in this
   case, implicit null).

   After IGP convergence, B's MPLS entry to Z will become:

   - Incoming label: local LDB label bound by B for FEC Z
       Outgoing label: LDP label bound by C for FEC Z
       Outgoing nhop: C

   And the traffic XZ travels again over the LDP LSP.



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   Conclusion: the operator has eliminated its second problem:
   guaranteed FRR coverage is provided.  The steady-state traffic is
   still transported over LDP.  The SR deployment is confined to the
   area where these benefits are required.

6.  Inter-AS Option C, Carrier's Carrier and Seamless MPLS

   PE1---R1---B1---B2---R2---PE2
   <----------->   <----------->
        AS1            AS2

                        Figure 5: Inter-AS Option C

   In Inter-AS Option C [RFC4364], B2 advertises to B1 a BGP3107 route
   for PE2 and B1 reflects it to its internal peers, such as PE1.  PE1
   learns from a service route reflector a service route whose nhop is
   PE2.  PE1 resolves that service route on the BGP3107 route to PE2.
   That BGP3107 route to PE2 is itself resolved on the AS1 IGP route to
   B1.

   If AS1 operates SR, then the tunnel from PE1 to B1 is provided by the
   node segment from PE1 to B1.

   PE1 sends a service packet with three labels: the top one is the node
   segment to B1, the next-one is the BGP3107 label provided by B1 for
   the route "PE2" and the bottom one is the service label allocated by
   PE2.

   The same straightforward SR applicability is derived for CsC and
   Seamless MPLS ([I-D.ietf-mpls-seamless-mpls]).

7.  IANA Considerations

   TBD

8.  Manageability Considerations

   TBD

9.  Security Considerations

   TBD

10.  Acknowledgements

   We would like to thank Pierre Francois and Ruediger Geib for their
   contribution to the content of this document.




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11.  References

11.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997.

   [RFC4364]  Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
              Networks (VPNs)", RFC 4364, February 2006.

11.2.  Informative References

   [I-D.ietf-mpls-seamless-mpls]
              Leymann, N., Decraene, B., Filsfils, C., Konstantynowicz,
              M., and D. Steinberg, "Seamless MPLS Architecture", draft-
              ietf-mpls-seamless-mpls-07 (work in progress), June 2014.

   [I-D.ietf-spring-segment-routing]
              Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
              Litkowski, S., Horneffer, M., Shakir, R., Tantsura, J.,
              and E. Crabbe, "Segment Routing Architecture", draft-ietf-
              spring-segment-routing-01 (work in progress), February
              2015.

   [I-D.ietf-spring-segment-routing-mpls]
              Filsfils, C., Previdi, S., Bashandy, A., Decraene, B.,
              Litkowski, S., Horneffer, M., Shakir, R., Tantsura, J.,
              and E. Crabbe, "Segment Routing with MPLS data plane",
              draft-ietf-spring-segment-routing-mpls-00 (work in
              progress), December 2014.

Authors' Addresses

   Clarence Filsfils (editor)
   Cisco Systems, Inc.
   Brussels
   BE

   Email: cfilsfil@cisco.com


   Stefano Previdi (editor)
   Cisco Systems, Inc.
   Via Del Serafico, 200
   Rome  00142
   Italy

   Email: sprevidi@cisco.com



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   Ahmed Bashandy
   Cisco Systems, Inc.
   170, West Tasman Drive
   San Jose, CA  95134
   US

   Email: bashandy@cisco.com


   Bruno Decraene
   Orange
   FR

   Email: bruno.decraene@orange.com


   Stephane Litkowski
   Orange
   FR

   Email: stephane.litkowski@orange.com


   Martin Horneffer
   Deutsche Telekom
   Hammer Str. 216-226
   Muenster  48153
   DE

   Email: Martin.Horneffer@telekom.de


   Igor Milojevic
   Telekom Srbija
   Takovska 2
   Belgrade
   RS

   Email: igormilojevic@telekom.rs


   Rob Shakir
   British Telecom
   London
   UK

   Email: rob.shakir@bt.com




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   Saku Ytti
   TDC Oy
   Mechelininkatu 1a
   TDC  00094
   FI

   Email: saku@ytti.fi


   Wim Henderickx
   Alcatel-Lucent
   Copernicuslaan 50
   Antwerp  2018
   BE

   Email: wim.henderickx@alcatel-lucent.com


   Jeff Tantsura
   Ericsson
   300 Holger Way
   San Jose, CA  95134
   US

   Email: Jeff.Tantsura@ericsson.com


   Edward Crabbe
   Individual Contributor

   Email: edward.crabbe@gmail.com




















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