path: root/doc/rfc/rfc8385.txt

Internet Engineering Task Force (IETF)                          M. Umair
Request for Comments: 8385                                         Cisco
Category: Informational                               S. Kingston Smiler
ISSN: 2070-1721                                            PALC Networks
                                                         D. Eastlake 3rd
                                                                  Huawei
                                                                 L. Yong
                                                             Independent
                                                               June 2018


          Transparent Interconnection of Lots of Links (TRILL)
                    Transparent Transport over MPLS

Abstract

   This document specifies methods to interconnect multiple TRILL
   (Transparent Interconnection of Lots of Links) sites with an
   intervening MPLS network using existing TRILL and VPLS (Virtual
   Private LAN Service) standards.  This document addresses two
   problems: 1) providing connection between more than two TRILL sites
   that are separated by an MPLS provider network and 2) providing a
   single logical virtualized TRILL network for different tenants that
   are separated by an MPLS provider network.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   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).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc8385.











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Copyright Notice

   Copyright (c) 2018 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
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1. Introduction ....................................................3
      1.1. Terminology ................................................3
   2. TRILL-over-MPLS Model ...........................................5
   3. VPLS Model ......................................................5
      3.1. Entities in the VPLS Model .................................6
      3.2. TRILL Adjacency for VPLS Model .............................7
      3.3. MPLS Encapsulation for VPLS Model ..........................7
      3.4. Loop-Free Provider PSN/MPLS ................................7
      3.5. Frame Processing ...........................................7
   4. VPTS Model ......................................................7
      4.1. Entities in the VPTS Model .................................9
           4.1.1. TRILL Intermediate Router (TIR) ....................10
           4.1.2. Virtual TRILL Switch/Service Domain (VTSD) .........10
      4.2. TRILL Adjacency for VPTS Model ............................10
      4.3. MPLS Encapsulation for VPTS Model .........................10
      4.4. Loop-Free Provider PSN/MPLS ...............................11
      4.5. Frame Processing ..........................................11
           4.5.1. Multi-destination Frame Processing .................11
           4.5.2. Unicast Frame Processing ...........................11
   5. VPTS Model versus VPLS Model ...................................11
   6. Packet Processing between Pseudowires ..........................12
   7. Efficiency Considerations ......................................12
   8. Security Considerations ........................................12
   9. IANA Considerations ............................................13
   10. References ....................................................13
       10.1. Normative References ....................................13
       10.2. Informative References ..................................14
   Acknowledgements ..................................................15
   Authors' Addresses ................................................16





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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 that belong
      to a single TRILL network and are separated by an MPLS provider
      network using [RFC7173].  (Herein, this is 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,
      this is for providing connection between TRILL sites belonging to
      a tenant/tenants over a MPLS provider network.  (Herein, this is
      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 document
   also addresses the problem of multi-tenancy by isolating one tenant's
   traffic from the other.

   [RFC7173] mentions how to interconnect a pair of 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 and terms used in this document include the following:

   AC         - Attachment Circuit [RFC4664]

   Data Label - VLAN Label or Fine-Grained Label




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   database   - IS-IS link state database

   ECMP       - Equal-Cost Multipath

   FGL        - Fine-Grained Labeling [RFC7172]

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

   LAN        - Local Area Network

   MPLS       - Multiprotocol Label Switching

   PBB        - Provider Backbone Bridging

   PE         - Provider Edge device

   PSN        - Packet Switched Network

   PW         - Pseudowire [RFC4664]

   TIR        - TRILL Intermediate Router (Device 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









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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".

3.  VPLS Model

   Figure 1 shows the topological model of TRILL over MPLS using the
   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 3 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.









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      +-----+         ............................          +-----+
      |RBat1+---+     . ++++++++++++++++++++++++ .      +---|RBbt1|
      +-----+   |     . +                      + .      |   +-----+
      Tenant1   |    +----+                   +----+    |   Tenant1
      Site 1    +----|VSI1|                   |VSI1|----+   Site 2
                +----|VSI2|    MPLS  Cloud    |VSI2|----+
                |    +----+                   +----+    |
      +-----+   |     . +                       + .     |   +-----+
      |RBat2+---+     . +++++++++ +----+ ++++++++ .     +---|RBbt2|
      +-----+         ............|VSI1|...........         +-----+
      Tenant2                     |VSI2|                    Tenant2
      Site 1                      +----+                    Site 2
                                    |
                                 +-----+
                                 |RBct2|
                                 +-----+
                             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 are connected via a 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 Customer Edge (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 campus are defined in [RFC6325] as updated
   by [RFC7780].





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3.2.  TRILL Adjacency for VPLS Model

   As specified in Section 3, 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 Section 3.3.

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 the
   entry PE and removed by the exit PE.

3.4.  Loop-Free Provider PSN/MPLS

   No explicit handling is required to avoid a loop-free topology.  The
   "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].

4.  VPTS Model

   The Virtual Private TRILL Service (VPTS) is a Layer 2 TRILL service
   that emulates TRILL service across a Wide Area Network (WAN).  VPTS
   is similar to what VPLS does for a bridged 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 TRILL Intermediate
   Routers (TIRs), and the VSIs are replaced with Virtual TRILL Switch
   Domains (VTSDs).  The TIR devices must be capable of supporting both




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   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 an RBridge.

   Below are some of the reasons for interconnecting TRILL sites without
   isolating the TRILL control plane of one TRILL site from other sites.

   1) Nickname uniqueness: One of the basic requirements of TRILL is
      that RBridge nicknames are unique within the campus [RFC6325].  If
      we segregate the control plane of one TRILL site from other TRILL
      sites 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 packets had no
      receivers.  The TRILL Reverse Path Forwarding (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.

        +-----+                                               +-----+
        | RBa +---+      ...........................      +---| RBb |
        +-----+   |      .                         .      |   +-----+
        Site 1    |    +----+                   +----+    |    Site 2
                  +----|TIR1|                   |TIR2|----+
                       +----+    MPLS Cloud     +----+
                         .                         .
                         .         +----+          .
                         ..........|TIR3|...........
                                   +----+      ^
                                      |        |
                                      |        +-- Emulated TRILL
                                   +-----+
                                   | RBc |
                                   +-----+
                                   Site 3

       Figure 3: Topological Model of VPTS/TIR Connecting 3 TRILL Sites





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   In Figure 3, Site 1, Site 2, and Site 3 (running the TRILL protocol)
   are connected to TIR devices.  These TIR devices, along with the MPLS
   cloud, look like a 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 the 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.

       +-----+          ............................         +-----+
       |RBat1+---+      . ######################## .     +---|RBbt1|
       +-----+   |      . #                      # .     |   +-----+
       Tenant1   |    +-----+                 +-----+    |   Tenant1
       Site 1    +----|VTSD1|                 |VTSD1|----+   Site 2
                 +----|VTSD2|   MPLS  Cloud   |VTSD2|----+
                 |    +-----+                 +-----+    |
       +-----+   |      . #                       # .    |   +-----+
       |RBat2+---+      . #########+-----+######### .    +---|RBbt2|
       +-----+          ...........|VTSD1|...........        +-----+
       Tenant2                     |VTSD2|          ^        Tenant2
       Site 1                      +-----+          |        Site 2
                                      |             |
                                   +-----+          +-----Emulated
                                   |RBct2|                  TRILL
                                   +-----+
                                Tenant2 Site 3

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

                   Figure 4: Topological Model of VPTS/TIR
                   Connecting 2 Tenants with 3 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].




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   This model introduces two new entities, TIR and VTSD, which are
   described below.

4.1.1.  TRILL Intermediate Router (TIR)

   The TIRs 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 that
   provides transparent bridging functionality in the PE device is
   replaced with VTSD in a TIR.

4.1.2.  Virtual TRILL Switch/Service Domain (VTSD)

   The VTSD is similar to the VSI (Layer 2 bridge) in the VPLS model,
   but the VTSD acts as a TRILL RBridge.  The VTSD is a superset of the
   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
   kept by the RBridge on a per-tenant basis.  The VTSD must also take
   care of segregating one tenant's traffic from another's.  Each VTSD
   will have its own nickname for each tenant.  If a TIR supports 10
   TRILL tenants, it needs to be assigned with 10 TRILL nicknames, one
   for the nickname space of each of its tenants, and run 10 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 a TRILL adjacency with the
   corresponding VTSDs present in its peer VPTS neighbor and also with
   the neighboring RBridges of 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.





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4.4.  Loop-Free Provider PSN/MPLS

   This model isn't required to employ the "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 the TRILL base protocol standard [RFC6325] as updated by
   [RFC7780].

4.5.  Frame Processing

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

4.5.1.  Multi-destination Frame Processing

   Any multi-destination (unknown unicast, multicast, or broadcast, as
   indicated by the 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 the 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 the destination,
   then VTSD should be capable of doing ECMP for those equal-cost paths.

5.  VPTS Model versus VPLS Model

   The 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.  In contrast, 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.








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6.  Packet Processing between Pseudowires

   Whenever a packet gets received over a pseudowire, a VTSD will
   decapsulate the MPLS headers then check the TRILL header.  If the
   egress nickname in the TRILL header is for a TRILL site located
   beyond another pseudowire, then the VTSD will encapsulate the packet
   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 that are destined to TIR3 are received from the
   pseudowire between TIR1 and TIR3, the VTSD inside TIR3 will
   decapsulate the MPLS headers, then check the TRILL header's egress
   nickname field.  If the egress nickname indicates it is destined for
   the RBridge in Site 3, then the packet will be sent to RBc; if the
   egress nickname is located at Site 2, VTSD will add MPLS headers for
   the pseudowire between TIR3 and TIR2 and forward the packet on that
   pseudowire.

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 located in every TRILL site.  This will
   prevent data packets from being received at TRILL sites where end-
   station service is not enabled for that data packet.

8.  Security Considerations

   This document specifies methods using existing standards and
   facilities in ways that do not create new security problems.

   For general VPLS security considerations, including discussion of
   isolating customers from each other, see [RFC4761] and [RFC4762].

   For security considerations for transport of TRILL by pseudowires,
   see [RFC7173].  In particular, since pseudowires are supported by
   MPLS or IP, which are in turn supported by a link layer, that
   document recommends using IP security, such as IPsec [RFC4301] or
   DTLS [RFC6347], or the lower link-layer security, such as MACSEC
   [802.1AE] for Ethernet links.

   Transmission outside the customer environment through the provider
   environment, as described in this document, increases risk of
   compromise or injection of false data through failure of tenant
   isolation or by the provider.  In the VPLS model (Section 3), the use
   of link encryption and authentication between the CEs of a tenant
   that is being connected through provider facilities should be a good



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   defense.  In the VPTS model (Section 4), it is assumed that the CEs
   will peer with virtual TRILL switches of the provider network, and
   thus link security between TRILL switch ports is inadequate as it
   will terminate at the edge PE.  Thus, encryption and authentication
   from end station to end station and authentication are more
   appropriate for the VPTS model.

   For added security against the compromise of data, end-to-end
   encryption and authentication should be considered; that is,
   encryption and authentication from source end station to destination
   end station.  This would typically be provided by IPsec [RFC4301] or
   DTLS [RFC6347] or other protocols convenient to protect the
   information of concern.

   For general TRILL security considerations, see [RFC6325].

9.  IANA Considerations

   This document has no IANA actions.

10.  References

10.1.  Normative References

   [IS-IS]    ISO, "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>.








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   [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>.

10.2.  Informative References

   [802.1AE]  IEEE, "IEEE Standard for Local and Metropolitan Area
              Networks: Media Access Control (MAC) Security", IEEE Std
              802.1AE, DOI 10.1109/IEEESTD.2006.245590.

   [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>.

   [RFC4301]  Kent, S. and K. Seo, "Security Architecture for the
              Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
              December 2005, <https://www.rfc-editor.org/info/rfc4301>.

   [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>.

   [RFC6347]  Rescorla, E. and N. Modadugu, "Datagram Transport Layer
              Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
              January 2012, <https://www.rfc-editor.org/info/rfc6347>.

   [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>.





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   [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>.

Acknowledgements

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









































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Authors' Addresses

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

   Email: mohammed.umair2@gmail.com


   S. Kingston Smiler
   PALC NETWORKS PVT LTD
   Envision Technology Center
   #119, 1st Floor, Road No.3
   EPIP Area Phase 1, Whitefield
   Near Vydehi Hospital
   Bengaluru - 560066, Karnataka
   India

   Email: kingstonsmiler@gmail.com


   Donald Eastlake 3rd
   Huawei Technologies
   155 Beaver Street
   Milford, MA  01757
   United States of America

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


   Lucy Yong
   Independent

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












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