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TRILL Transparent Transport over MPLS
draft-ietf-trill-transport-over-mpls-07

The information below is for an old version of the document.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 8385.
Authors Mohammed Umair , Kingston Smiler , Donald E. Eastlake 3rd , Lucy Yong
Last updated 2018-03-08 (Latest revision 2018-01-19)
Replaces draft-muks-trill-transport-over-mpls
RFC stream Internet Engineering Task Force (IETF)
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Stream WG state Submitted to IESG for Publication
Document shepherd Susan Hares
Shepherd write-up Show Last changed 2018-02-19
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Needs a YES.
Responsible AD Alia Atlas
Send notices to "Susan Hares" <shares@ndzh.com>
IANA IANA review state IANA OK - No Actions Needed
draft-ietf-trill-transport-over-mpls-07
INTERNET-DRAFT                                            Mohammed Umair
Intended Status: Informational
                                                Kingston Smiler Selvaraj
                                                              IPInfusion
                                                     Donald Eastlake 3rd
                                                                  Huawei
                                                               Lucy Yong
                                                                    Self
Expires: July 18, 2018                                  January 19, 2018

                 TRILL Transparent Transport over MPLS
               draft-ietf-trill-transport-over-mpls-07.txt

Abstract

   This document specifies methods to interconnect multiple Transparent
   Interconnection of Lots of links (TRILL) sites with an intervening
   MPLS network using existing TRILL and VPLS standards. This draft
   addresses two problems as follows:

   1) Providing connection between more than two TRILL sites that are
      separated by an MPLS provider network.

   2) Providing a single logical virtualized TRILL network for different
      tenants that are separated by an MPLS provider network.

Status of This Memo

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

   Distribution of this document is unlimited. Comments should be sent
   to the authors or the TRILL working group mailing list:
   trill@ietf.org.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   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."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/1id-abstracts.html. The list of Internet-Draft
   Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

M.Umair, K.Smiler, et al                                        [Page 1]
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Table of Contents

      1. Introduction............................................3
      1.1. Terminology...........................................3

      2. TRILL Over MPLS Model...................................5

      3. VPLS Model..............................................6
      3.1 Entities in the VPLS Model.............................7
      3.2 TRILL Adjacency for VPLS model.........................8
      3.3 MPLS encapsulation for VPLS model......................8
      3.4 Loop Free provider PSN/MPLS............................8
      3.5 Frame Processing.......................................8

      4. VPTS Model..............................................9
      4.1 Entities in the VPTS Model............................11
      4.1.1 TRILL Intermediate Routers (TIR)....................11
      4.1.2 Virtual TRILL Switch/Service Domain (VTSD)..........12
      4.2 TRILL Adjacency for VPTS model........................12
      4.3 MPLS encapsulation for VPTS model.....................12
      4.4 Loop Free provider PSN/MPLS...........................12
      4.5. Frame Processing.....................................13
      4.5.1 Multi-Destination Frame Processing..................13
      4.5.2 Unicast Frame Processing............................13

      5. VPTS Model Versus VPLS Model...........................14
      6. Packet Processing Between Pseudowires..................14
      7. Efficiency Considerations..............................15

      8. Security Considerations................................15
      9. IANA Considerations....................................15

      Normative References......................................16
      Informative References....................................17

      Acknowledgements..........................................18
      Authors' Addresses........................................18

M.Umair, K.Smiler, et al                                        [Page 2]
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1. Introduction

   The IETF Transparent Interconnection of Lots of Links (TRILL)
   protocol [RFC6325] [RFC7177] [RFC7780] provides transparent
   forwarding in multi-hop networks with arbitrary topology and link
   technologies using a header with a hop count and link-state routing.
   TRILL provides optimal pair-wise forwarding without configuration,
   safe forwarding even during periods of temporary loops, and support
   for multipathing of both unicast and multicast traffic. Intermediate
   Systems (ISs) implementing TRILL are called Routing Bridges
   (RBridges) or TRILL Switches

   This document, in conjunction with [RFC7173] on TRILL Transport using
   Pseudowires, addresses two problems:

   1) Providing connection between more than two TRILL sites belongs to
      a single TRILL network that are separated by an MPLS provider
      network using [RFC7173]. (Herein also called problem statement 1.)

   2) Providing a single logical virtualized TRILL network for different
      tenants that are separated by an MPLS provider network. In short
      providing connection between TRILL sites belonging to a
      tenant/tenants over a MPLS provider network. (Herein also called
      problem statement 2.)

   A tenant is the administrative entity on whose behalf their
   associated services are managed. Here tenant refers to a TRILL campus
   that is segregated from other tenants for security reasons.

   A key multi-tenancy requirement is traffic isolation so that one
   tenant's traffic is not visible to any other tenant. This draft also
   addresses the problem of multi-tenancy by isolating one tenant's
   traffic from the other.

   [RFC7173] mentions how to interconnect a pair of Transparent
   Interconnection of Lots of Links (TRILL) switch ports using
   pseudowires.  This document explains, how to connect multiple TRILL
   sites (not limited to only two sites) using the mechanisms and
   encapsulations defined in [RFC7173].

1.1. Terminology

   Acronyms used in this document include the following:

         AC        - Attachment Circuit [RFC4664]

         Data Label - VLAN or FGL

M.Umair, K.Smiler, et al                                        [Page 3]
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         database  - IS-IS link state database

         ECMP      - Equal Cost Multi Path

         FGL       - Fine-Grained Labeling [RFC7172]

         IS-IS     - Intermediate System to Intermediate System [IS-IS]

         LDP       - Label Distribution Protocol

         LAN       - Local Area Network

         MPLS      - Multi-Protocol Label Switching

         PBB       - Provider Backbone Bridging

         PE        - Provider Edge Device

         PSN       - Packet Switched Network

         PW        - Pseudowire [RFC4664]

         TIR       - TRILL Intermediate Router (Devices that has both
                     IP/MPLS and TRILL functionality)

         TRILL     - Transparent Interconnection of Lots of Links OR
                     Tunneled Routing in the Link Layer

         TRILL Site - A part of a TRILL campus that contains at least
                     one RBridge.

         VLAN      - Virtual Local Area Network.

         VPLS      - Virtual Private LAN Service

         VPTS      - Virtual Private TRILL Service

         VSI       - Virtual Service Instance [RFC4664]

         VTSD      - Virtual TRILL Switch Domain OR Virtual TRILL
                     Service Domain.  A Virtual RBridge that segregates
                     one tenant's TRILL database as well as traffic from
                     the other.

         WAN       - Wide Area Network

M.Umair, K.Smiler, et al                                        [Page 4]
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2. TRILL Over MPLS Model

   TRILL Over MPLS can be achieved in two different ways.

         a) the VPLS Model for TRILL
         b) the VPTS Model/TIR Model for TRILL

   Both these models can be used to solve problem statements 1 and 2.
   Herein the VPLS Model for TRILL is also called Model 1 and the VPTS
   Model/TIR Model is also called Model 2.

M.Umair, K.Smiler, et al                                        [Page 5]
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3. VPLS Model

   Figure 1 shows the topological model of TRILL over MPLS using VPLS
   model. The PE routers in the below topology model should support all
   the functional Components mentioned in [RFC4664].

          +-----+                                               +-----+
          | RBa +---+      ...........................      +---| RBb |
          +-----+   |      .                         .      |   +-----+
          Site 1    |    +----+                   +----+    |    Site 2
                    +----|PE1 |                   |PE2 |----+
                         +----+    MPLS Cloud     +----+
                           .                         .
                           .         +----+          .
                           ..........|PE3 |...........
                                     +----+      ^
                                        |        |
                                        |        +-- Emulated LAN
                                     +-----+
                                     | RBc |
                                     +-----+
                                     Site 3

              Figure 1. Topological Model of TRILL over MPLS
                       connecting three TRILL Sites

   Figure 2 below shows the topological model of TRILL over MPLS to
   connect multiple TRILL sites belonging to a tenant. (Tenant here is a
   TRILL campus, not a specific Data label.) VSI1 and VSI2 are two
   Virtual Service Instances that segregate Tenant1's traffic from other
   tenant traffic.  VSI1 will maintain its own database for Tenant1,
   similarly VSI2 will maintain its own database for Tenant2.

M.Umair, K.Smiler, et al                                        [Page 6]
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   +-----+         ............................          +-----+
   |RBat1+---+     . ++++++++++++++++++++++++ .      +---|RBbt1|
   +-----+   |     . +                      + .      |   +-----+
Tenant1 Site 1  |    +----+                   +----+    | Tenant1 Site2
             +----|VSI1|                   |VSI1|----+
             +----|VSI2|    MPLS  Cloud    |VSI2|----+
             |    +----+                   +----+    |
   +-----+   |     . +                       + .     |   +-----+
   |RBat2+---+     . +++++++++ +----+ ++++++++ .     +---|RBbt2|
   +-----+         ............|VSI1|...........         +-----+
Tenant2 Site 2                    |VSI2|          ^      Tenant2 Site2
                               +----+          |
                                 |             |
                              +-----+          +-----Emulated
                              |RBct2|                  LAN
                              +-----+
                          Tenant2 Site 3

   .... VSI1 Path
   ++++ VSI2 Path

                Figure 2. Topological Model for VPLS Model
                  connecting 2 Tenants with 3 sites each

   In this model, TRILL sites are connected to VPLS-capable PE devices
   that provide a logical interconnect, such that TRILL RBridges
   belonging to a specific tenant connected via an single bridged
   Ethernet. These PE devices are the same as the PE devices specified
   in [RFC4026]. The Attachment Circuit ports of PE Routers are layer 2
   switch ports that are connected to the RBridges at a TRILL site. Here
   each VPLS instance looks like an emulated LAN. This model is similar
   to connecting different RBridges by a layer 2 bridge domain (multi
   access link) as specified in [RFC6325]. This model doesn't requires
   any changes in PE routers to carry TRILL packets, as TRILL packets
   will be transferred transparently.

3.1 Entities in the VPLS Model

   The PE (VPLS-PE) and CE devices are defined in [RFC4026].

   The Generic L2VPN Transport Functional Components like Attachment
   Circuits, Pseudowires, VSI etc. are defined in [RFC4664].

   The RB (RBridge) and TRILL Sites are defined in [RFC6325] as updated
   by [RFC7780].

M.Umair, K.Smiler, et al                                        [Page 7]
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3.2 TRILL Adjacency for VPLS model

   As specified in section 3 of this document, the MPLS cloud looks like
   an emulated LAN (also called multi-access link or broadcast link).
   This results in RBridges at different sites looking like they are
   connected by a multi-access link. With such interconnection, the
   TRILL adjacencies over the link are automatically discovered and
   established through TRILL IS-IS control messages [RFC7177]. These IS-
   IS control messages are transparently forwarded by the VPLS domain,
   after doing MPLS encapsulation as specified in the section 3.4.

3.3 MPLS encapsulation for VPLS model

   Use of VPLS [RFC4762] [RFC4761] to interconnect TRILL sites requires
   no changes to a VPLS implementation, in particular the use of
   Ethernet pseudowires between VPLS PEs. A VPLS PE receives normal
   Ethernet frames from an RBridge (i.e., CE) and is not aware that the
   CE is an RBridge device. As an example, an MPLS-encapsulated TRILL
   packet within the MPLS network can use the format illustrated in
   Appendix A of [RFC7173] for the non-PBB case. For the PBB case,
   additional header fields illustrated in [RFC7041] can be added by
   entry PE and removed by the exit PE.

3.4 Loop Free provider PSN/MPLS

   No explicit handling is required to avoid loop free topology. Split
   Horizon technique specified in [RFC4664] will take care of avoiding
   loops in the provider PSN network.

3.5 Frame Processing

   The PE devices transparently process the TRILL control and data
   frames. Procedures to forward the frames are defined in [RFC4664].

M.Umair, K.Smiler, et al                                        [Page 8]
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4. VPTS Model

   The VPTS (Virtual Private TRILL Service) is a L2 TRILL service, that
   emulates TRILL service across a Wide Area Network (WAN). VPTS is
   similar to what VPLS does for bridge core but provides a TRILL core.
   VPLS provides "Virtual Private LAN Service" for different customers.
   VPTS provides "Virtual Private TRILL Service" for different TRILL
   tenants.

   Figure 3 shows the topological model of TRILL over MPLS using VPTS.
   In this model the PE routers are replaced with TIR (TRILL
   Intermediate Router) and VSI is replaced with VTSD (Virtual TRILL
   Switch Domain). The TIR devices must be capable of supporting both
   MPLS and TRILL as specified in section 4.1.1. The TIR devices are
   interconnected via PWs and appear as a unified emulated TRILL campus
   with each VTSD inside a TIR equivalent to a RBridge.

   Some of the reasons for interconnecting TRILL Sites without isolating
   the TRILL Control plane of one TRILL site from other sites are as
   described below.

   1) Nickname Uniqueness: One of the basic requirements of TRILL is
      that, RBridge Nicknames are unique within the campus [RFC6325]. If
      we segregate control plane of one TRILL site from other TRILL site
      and provide interconnection between these sites, it may result in
      Nickname collision.

   2) Distribution Trees and their pruning: When a TRILL Data packet
      traverses a Distribution Tree, it will stay on it even in other
      TRILL sites. If no end-station service is enabled for a particular
      Data Label in a TRILL site, the Distribution Tree may be pruned
      and TRILL data packets of that particular Data Label might never
      get to another TRILL site where the pckets had no receivers. The
      TRILL RPF check will always be performed on the packets that are
      received by TIRs through pseudowires.

   3) Hop Count values: When a TRILL data packet is received over a
      pseudowire by a TIR, the TIR does the processing of Hop Count
      defined in [RFC6325] and will not perform any resetting of Hop
      Count.

M.Umair, K.Smiler, et al                                        [Page 9]
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        +-----+                                               +-----+
        | RBa +---+      ...........................      +---| RBb |
        +-----+   |      .                         .      |   +-----+
        Site 1    |    +----+                   +----+    |    Site 2
                  +----|TIR1|                   |TIR2|----+
                       +----+    MPLS Cloud     +----+
                         .                         .
                         .         +----+          .
                         ..........|TIR3|...........
                                   +----+      ^
                                      |        |
                                      |        +-- Emulated TRILL
                                   +-----+
                                   | RBc |
                                   +-----+
                                   Site 3

                   Figure 3. Topological Model of VPTS/TIR
                         connecting three TRILL Sites

   In the above Figure 3, Site1, Site2 and Site3 (running the TRILL
   protocol) are connected to TIR Devices. These TIR devices, along with
   the MPLS cloud, look like an unified emulated TRILL network. Only the
   PE devices in the MPLS network should be replaced with TIRs so the
   intermediate Provider routers are agnostic to the TRILL protocol.

   Figure 4 below extends the topological model of TRILL over MPLS to
   connect multiple TRILL sites belonging to a tenant (tenant here is a
   campus, not a Data label) using VPTS model. VTSD1 and VTSD2 are two
   Virtual TRILL Switch Domains (Virtual RBridges) that segregate
   Tenant1's traffic from Tenant2's traffic. VTSD1 will maintain its own
   TRILL database for Tenant1. Similarly VTSD2 will maintain its own
   TRILL database for Tenant2.

M.Umair, K.Smiler, et al                                       [Page 10]
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    +-----+          ............................         +-----+
    |RBat1+---+      . ######################## .     +---|RBbt1|
    +-----+   |      . #                      # .     |   +-----+
Tenant1 Site 1|    +-----+                 +-----+    |  Tenant1 Site 2
              +----|VTSD1|                 |VTSD1|----+
              +----|VTSD2|   MPLS  Cloud   |VTSD2|----+
              |    +-----+                 +-----+    |
    +-----+   |      . #                       # .    |   +-----+
    |RBat2+---+      . #########+-----+######### .    +---|RBbt2|
    +-----+          ...........|VTSD1|...........        +-----+
Tenant2 Site2                   |VTSD2|          ^       Tenant2 Site 2
                                +-----+          |
                                   |             |
                                +-----+          +-----Emulated
                                |RBct2|                  TRILL
                                +-----+
                             Tenant2 Site 3

     .... VTSD1 Connectivity
     #### VTSD2 Connectivity

                  Figure 4. Topological Model of VPTS/TIR
                connecting 2 tenants with three TRILL Sites

4.1 Entities in the VPTS Model

   The CE devices are defined in [RFC4026].

   The Generic L2VPN Transport Functional Components like Attachment
   Circuits, Pseudowires etc. are defined in [RFC4664].

   The RB (RBridge) and TRILL Campus are defined in [RFC6325] as updated
   by [RFC7780].

   This model introduces two new entities called TIR and VTSD that are
   described below.

4.1.1 TRILL Intermediate Routers (TIR)

   The TIRs (TRILL Intermediate Routers) must be capable of running both
   VPLS and TRILL protocols. TIR devices are a superset of the VPLS-PE
   devices defined in [RFC4026] with the additional functionality of
   TRILL. The VSI instance that provides transparent bridging
   functionality in the PE device is replaced with VTSD in a TIR.

M.Umair, K.Smiler, et al                                       [Page 11]
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4.1.2 Virtual TRILL Switch/Service Domain (VTSD)

   The VTSD (Virtual Trill Switch Domain) is similar to VSI (layer 2
   bridge) in the VPLS model, but the VTSD acts as a TRILL RBridge. The
   VTSD is a superset of VSI and must support all the functionality
   provided by the VSI as defined in [RFC4026]. Along with VSI
   functionality, the VTSD must be capable of supporting TRILL protocols
   and forming TRILL adjacencies. The VTSD must be capable of performing
   all the operations that a standard TRILL Switch can do.

   One VTSD instance per tenant must be maintained, when multiple
   tenants are connected to a TIR. The VTSD must maintain all the
   information maintained by the RBridge on a per tenant basis. The VTSD
   must also take care of segregating one tenant traffic from other.
   Each VTSD will have its own nickname for each tenant, If a TIR
   supports 10 TRILL tenants, it needs to be assigned with ten TRILL
   nicknames, one for the nickname space of each of its tenants, and run
   ten copies of TRILL protocols, one for each tenant. It is possible
   that it would have the same nickname for two or more tenants but,
   since the TRILL data and control traffic are separated for the
   tenants, there is no confusion.

4.2 TRILL Adjacency for VPTS model

   The VTSD must be capable of forming TRILL adjacency with the
   corresponding VTSDs present in its peer VPTS neighbor, and also the
   neighbor RBridges present in the TRILL sites. The procedure to form
   TRILL Adjacency is specified in [RFC7173] and [RFC7177].

4.3 MPLS encapsulation for VPTS model

   The VPTS model uses PPP or Ethernet pseudowires for MPLS
   encapsulation as specified in [RFC7173], and requires no changes in
   the packet format in that RFC. In accordance with [RFC7173], the PPP
   encapsulation is the default.

4.4 Loop Free provider PSN/MPLS

   This model isn't required to employ Split Horizon mechanism in the
   provider PSN network, as TRILL takes care of Loop free topology using
   Distribution Trees. Any multi-destination packet will traverse a
   distribution tree path. All distribution trees are calculated based
   on TRILL base protocol standard [RFC6325] as updated by [RFC7780].

M.Umair, K.Smiler, et al                                       [Page 12]
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4.5. Frame Processing

   This section specifies multi-destination and unicast frame processing
   in VPTS/TIR model.

4.5.1 Multi-Destination Frame Processing

   Any multi-destination (unknown unicast, multicast or broadcast, as
   indicated by multi-destination bit in the TRILL Header) packets
   inside a VTSD will be processed or forwarded through the distribution
   tree for which they were encapsulated on TRILL ingress. If any multi-
   destination packet is received from the wrong pseudowire at a VTSD,
   the TRILL protocol running in the VTSD will perform an RPF check as
   specified in [RFC7780] and drop the packet.

   The Pruning mechanism in Distribution Trees, as specified in
   [RFC6325] and [RFC7780], can also be used to avoid forwarding of
   multi-destination data packets on the branches where there are no
   potential destinations.

4.5.2 Unicast Frame Processing

   Unicast packets are forwarded in same way they get forwarded in a
   standard TRILL Campus as specified in [RFC6325]. If multiple equal
   cost paths are available over pseudowires to reach destination, then
   VTSD should be capable of doing ECMP for them.

M.Umair, K.Smiler, et al                                       [Page 13]
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5. VPTS Model Versus VPLS Model

   VPLS Model uses a simpler loop-breaking rule: the "split horizon"
   rule, where a PE must not forward traffic from one PW to another in
   the same VPLS mesh, whereas the VPTS Model uses distribution Trees
   for loop free topology. As this is an emulated TRILL service, for
   interoperability purposes the VPTS model is the default.

6. Packet Processing Between Pseudowires

   Whenever a packet gets received over a pseudowire, a VTSD will
   decapsulate the MPLS headers followed by checking the TRILL header.
   If the egress nickname in the TRILL header is for a TRILL site
   located beyond another pseudowire, then VTSD will encapsulate with
   new MPLS headers and send it across the proper pseudowire.

   For example in figure 3, consider that the pseudowire between TIR1
   and TIR2 fails, Then TIR1 will communicate with TIR2 via TIR3,
   whenever packets which are destined to TIR3 gets received from
   pseudowire between TIR1 and TIR3, VTSD inside TIR3 will decapsulate

   the MPLS headers, then check the TRILL header's egress nickname
   field. If the egress nickname indicate it is destained for the
   RBridge in site3 then the packet will be sent to RBc, if the egress
   nickname is located at site2, VTSD will add MPLS headers for the
   pseudowire between TIR3 and TIR2 and forward the packet on that
   pseudowire.

M.Umair, K.Smiler, et al                                       [Page 14]
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7. Efficiency Considerations

   Since the VPTS Model uses Distribution trees for processing of multi-
   destination data packets, it is always advisable to have at least one
   Distribution tree root to be located in every TRILL site. This will
   avoid data packets getting received at TRILL sites where end-station
   service is not enabled for that data packet.

8. Security Considerations

   As an informational document specifying methods that use only
   existing standards and facilities, this document has no effect on
   security.

   For general TRILL security considerations, see [RFC6325]

   For transport of TRILL by Pseudowires security consideration, see
   [RFC7173].

   For general VPLS security considerations, see [RFC4761] and [RFC4762]

9. IANA Considerations

   This document requires no IANA actions. RFC Editor: Please delete
   this section before publication

M.Umair, K.Smiler, et al                                       [Page 15]
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Normative References

   [IS-IS] "Intermediate system to Intermediate system routeing
         information exchange protocol for use in conjunction with the
         Protocol for providing the Connectionless-mode Network Service
         (ISO 8473)", ISO/IEC 10589:2002, 2002".

   [RFC4761] Kompella, K., Ed., and Y. Rekhter, Ed., "Virtual Private
         LAN Service (VPLS) Using BGP for Auto-Discovery and Signaling",
         RFC 4761, DOI 10.17487/RFC4761, January 2007, <https://www.rfc-
         editor.org/info/rfc4761>.

   [RFC4762] Lasserre, M., Ed., and V. Kompella, Ed., "Virtual Private
         LAN Service (VPLS) Using Label Distribution Protocol (LDP)
         Signaling", RFC 4762, DOI 10.17487/RFC4762, January 2007,
         <https://www.rfc-editor.org/info/rfc4762>.

   [RFC6325] Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and A.
         Ghanwani, "Routing Bridges (RBridges): Base Protocol
         Specification", RFC 6325, DOI 10.17487/RFC6325, July 2011,
         <https://www.rfc-editor.org/info/rfc6325>.

   [RFC7173] Yong, L., Eastlake 3rd, D., Aldrin, S., and J. Hudson,
         "Transparent Interconnection of Lots of Links (TRILL) Transport
         Using Pseudowires", RFC 7173, DOI 10.17487/RFC7173, May 2014,
         <https://www.rfc-editor.org/info/rfc7173>.

   [RFC7177] Eastlake 3rd, D., Perlman, R., Ghanwani, A., Yang, H., and
         V. Manral, "Transparent Interconnection of Lots of Links
         (TRILL): Adjacency", RFC 7177, DOI 10.17487/RFC7177, May 2014,
         <https://www.rfc-editor.org/info/rfc7177>.

   [RFC7780] Eastlake 3rd, D., Zhang, M., Perlman, R., Banerjee, A.,
         Ghanwani, A., and S. Gupta, "Transparent Interconnection of
         Lots of Links (TRILL): Clarifications, Corrections, and
         Updates", RFC 7780, DOI 10.17487/RFC7780, February 2016,
         <https://www.rfc-editor.org/info/rfc7780>.

M.Umair, K.Smiler, et al                                       [Page 16]
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Informative References

   [RFC4026] Andersson, L. and T. Madsen, "Provider Provisioned Virtual
         Private Network (VPN) Terminology", RFC 4026, DOI
         10.17487/RFC4026, March 2005, <https://www.rfc-
         editor.org/info/rfc4026>.

   [RFC4664] Andersson, L., Ed., and E. Rosen, Ed., "Framework for Layer
         2 Virtual Private Networks (L2VPNs)", RFC 4664, DOI
         10.17487/RFC4664, September 2006, <https://www.rfc-
         editor.org/info/rfc4664>.

   [RFC7041] Balus, F., Ed., Sajassi, A., Ed., and N. Bitar, Ed.,
         "Extensions to the Virtual Private LAN Service (VPLS) Provider
         Edge (PE) Model for Provider Backbone Bridging", RFC 7041, DOI
         10.17487/RFC7041, November 2013, <https://www.rfc-
         editor.org/info/rfc7041>.

   [RFC7172] Eastlake 3rd, D., Zhang, M., Agarwal, P., Perlman, R., and
         D. Dutt, "Transparent Interconnection of Lots of Links (TRILL):
         Fine-Grained Labeling", RFC 7172, DOI 10.17487/RFC7172, May
         2014, <https://www.rfc-editor.org/info/rfc7172>.

M.Umair, K.Smiler, et al                                       [Page 17]
INTERNET-DRAFT                     TRILL Transparent Transport over MPLS

Acknowledgements

   The contributions of Andrew G. Malis is gratefully acknowledged in
   improving the quality of this document.

   The document was prepared in raw nroff. All macros used were defined
   within the source file.

Authors' Addresses

      Mohammed Umair
      Cisco Systems
      SEZ, Cessna Business Park
      Sarjapur - Marathahalli Outer Ring road
      Bengaluru - 560103, India

      EMail: mohammed.umair2@gmail.com

      Kingston Smiler Selvaraj
      IPInfusion
      RMZ Centennial
      Mahadevapura Post
      Bangalore - 560048 India

      EMail: kingstonsmiler@gmail.com

      Donald E. Eastlake 3rd
      Huawei Technologies
      155 Beaver Street
      Milford, MA  01757
      USA

      Phone: +1-508-333-2270
      EMail: d3e3e3@gmail.com

      Lucy Yong
      Self

      Phone: +1-469-227-5837
      EMail: lucyyong@gmail.com

M.Umair, K.Smiler, et al                                       [Page 18]
INTERNET-DRAFT                     TRILL Transparent Transport over MPLS

Copyright, Disclaimer, and Additional IPR Provisions

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M.Umair, K.Smiler, et al                                       [Page 19]