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+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.
+
+
+
+
+
+
+
+
+
+
+
+Umair, et al.                 Informational                     [Page 1]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+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
+
+
+
+
+
+Umair, et al.                 Informational                     [Page 2]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+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
+
+
+
+
+Umair, et al.                 Informational                     [Page 3]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+   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
+
+
+
+
+
+
+
+
+
+Umair, et al.                 Informational                     [Page 4]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+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.
+
+
+
+
+
+
+
+
+
+Umair, et al.                 Informational                     [Page 5]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+      +-----+         ............................          +-----+
+      |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].
+
+
+
+
+
+Umair, et al.                 Informational                     [Page 6]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+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
+
+
+
+
+Umair, et al.                 Informational                     [Page 7]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+   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
+
+
+
+
+
+Umair, et al.                 Informational                     [Page 8]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+   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].
+
+
+
+
+Umair, et al.                 Informational                     [Page 9]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+   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.
+
+
+
+
+
+Umair, et al.                 Informational                    [Page 10]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+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.
+
+
+
+
+
+
+
+
+Umair, et al.                 Informational                    [Page 11]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+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
+
+
+
+Umair, et al.                 Informational                    [Page 12]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+   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>.
+
+
+
+
+
+
+
+
+Umair, et al.                 Informational                    [Page 13]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+   [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>.
+
+
+
+
+
+Umair, et al.                 Informational                    [Page 14]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+   [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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+Umair, et al.                 Informational                    [Page 15]
+
+RFC 8385          TRILL Transparent Transport over MPLS        June 2018
+
+
+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
+
+
+
+
+
+
+
+
+
+
+
+
+Umair, et al.                 Informational                    [Page 16]
+