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Versions: (draft-perlman-trill-rbridge-vlan-mapping) 00 01 02 03 04 05 06 07 08 09 10

TRILL Working Group                                        Radia Perlman
INTERNET-DRAFT                                                Intel Labs
Intended status: Proposed Standard                     Anil Rijhsinghani
                                                           HP Networking
                                                         Donald Eastlake
                                                           Ayan Banerjee
                                                             Dinesh Dutt
Expires July 3, 2014                                     January 4, 2014

                TRILL: Campus Label and Priority Regions


   Within a TRILL campus, the data label (VLAN or Fine Grained Label)
   and priority of TRILL encapsulated frames is preserved. However, in
   some cases it may be desired that data label and/or priority be
   mapped at the boundary between regions of such a campus. This
   document describes an optional TRILL switch feature to provide this

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 TRILL working group mailing list.

   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-

   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

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INTERNET-DRAFT                         TRILL: Label and Priority Regions

Table of Contents

      1. Introduction............................................3
      1.1 TRILL Campus Regions...................................4
      1.2 Terminology............................................5

      2. Internal and Cut Set Configuration and Mappings.........6
      2.1 Multiple Crossings.....................................7
      2.2 Native Frame Considerations............................8
      2.3 More than Two Regions..................................8
      2.4 Mapping Implementation.................................9

      3. End Node Address Learning Between Regions..............11
      4. Cut Set Attraction of Labels and Multicast.............12
      5. Advertisement of Label and Priority Mappings...........13

      6. IANA Considerations....................................13
      7. Security Considerations................................13
      8. Normative References...................................14
      9. Informative References.................................14

      Appendix Z: Change Summary................................15

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

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1. Introduction

   The IETF TRILL protocol provides transparent forwarding, with a
   number of additional features, by use of link state routing and
   encapsulation with a hop count as specified in [RFC6325] [RFC6327bis]
   [RFCclear] and [RFCfgl].

   Devices implementing the TRILL protocol are called TRILL switches or
   RBridges (Routing Bridges). A TRILL campus is an area of TRILL
   switches and possibly bridges bounded by and interconnecting end
   stations and Layer 3 routers, analogous to a customer bridge LAN
   (which is an area of bridges interconnecting end stations, Layer 3
   routers, and TRILL switches). In a TRILL campus, native frames (as
   defined in [RFC6325]), when they arrive at their first or ingress
   RBridge, are encapsulated, routed in encapsulated form via zero or
   more transit TRILL switches, and finally decapsulated and delivered
   by their egress TRILL switch or switches.

   TRILL switch ports have some features specified in IEEE 802.1Q as
   described in [RFC6325], with TRILL being implemented above those
   ports. Such ports provide for the association of incoming frames with
   a particular frame priority and customer VLAN (see Appendix D of
   [RFC6325]) or, in TRILL, 24-bit Fine Grained Label [RFCfgl].

   Bridge ports can map frame priorities, a process called "priority
   regeneration" in IEEE 802.1. In addition, some bridge ports/products
   provide a feature to map the customer VLAN of incoming VLAN tagged
   frames, a process of the type called "VLAN ID translation" in IEEE

   Using such port features, it is possible to configure RBridge ports
   to map the priority and/or VLAN of native frames being received for
   ingress or to map the priority and/or VLAN of the frame inside a
   TRILL Data packet after it has been decapsulated for egress through
   an output port. But priority and/or VLAN mapping of the outer
   priority and VLAN (Outer.VLAN) of a TRILL Data packet on Ethernet
   links has no effect on the Data Label (Inner.VLAN or Inner.FGL
   [RFCfgl]) in the encapsulated frame. In TRILL, the Data Label gives
   the real label and priority of the data and these are unaffected by
   any Ethernet port features that change only the Outer.VLAN priority
   or VLAN ID.

   (Note: VLAN mapping is also referred to in [RFC6325]. However, that
   reference concerns Outer.VLAN mapping within an Ethernet link between
   neighbor TRILL switches, a condition that may require the TRILL
   switches connected to such a link to take precautions as described in
   Section 4.4.5 of [RFC6325].)

   The default for TRILL is to provide connectivity between all end
   station and Layer 3 router ports in the same Data Lable. However,

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   there are cases where it may be desirable to have the same Data Label
   in different regions of a TRILL campus mean different things. In that
   case, it would be necessary for end stations or Layer 3 routers in
   that label not to be connected if they are in different regions. It
   might also be desirable to have connectivity between end stations in
   different regions that are in different Data Labels if those
   different labels in their different regions actually indicate
   membership in the same Layer 2 community. Similar circumstances can
   arise for priority.  This document describes how to achieve this
   though an optional TRILL switch feature.

   An example of where this feature might be useful would be the merger
   of two organizations which previously had separate networks. They
   might desire to combine these networks into a new unified network
   under unified control; however, for some period of time, there might
   be disagreements between the previously separate networks as to Data
   Label and/or priority assignments requiring mapping at any points of
   interconnection. If these were Layer 2 networks, and particularly if
   they were TRILL campuses, combination into a single unified TRILL
   campus would be natural; but, this would probably require mapping
   facilities, such as those specified herein, between the regions of
   the new unified campus that had previously been separate networks.

   Considerations related to service or S-VLANs are beyond the scope of
   this document but are an obvious extension.

1.1 TRILL Campus Regions

   The set of TRILL switches interconnecting different regions of a
   TRILL campus are known as the "cut set", meaning that if that set of
   switches is removed, the regions are disconnected from each other.

   TRILL switches in the cut set can be optionally configured to
   translate some set of Data Labels in one region to different Data
   Labels when forwarding from that region to another region and/or to
   block TRILL data packets with certain labels. They can be similarly
   configured for priority.

   This feature is accomplished solely by configuring TRILL switches in
   the cut set. No other TRILL switches need even be aware that the
   feature is in use. In particular, use of this feature has no effect
   on the path (sequence of RBridges) followed by TRILL Data packets
   (except that for multi-destination packets, tree pruning may be
   affected). The TRILL features of optimum routing and of optional
   multi-pathing of both unicast and multi-destination frames are

   This document explains how to implement this feature in TRILL

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   switches (RBridges).  We will usually assume there are two regions,
   "East" and "West", and RBridges RB1, RB2, and RB3 that interconnect
   the two regions and constitute the cut set as shown in Figure 1.
   Extension to more than two regions is straightforward and will also
   be briefly described.

          .   .   .         +-----+            .   .   .
        .   .   . + - - - - + RB1 + - - - - +    .   .   .
      .   W   .             +-----+            .   . E .
        . e .   .                                .   a   .
      .   s   .             +-----+                . s .   .
        . t .   .+ - - - - -+ RB2 + - - - - - - +.   t   .
      .   .   .            -+-+---+                .   .   .
        . R .   .        /    |      _ _ _ _ _ _+.   R   .   .
          e   .  + - - -      |    /               . e .   .
        . g .   .           +-+---+              .   g   .   .
      .   i   .   .+ - - - -+ RB3 + - - - - - - - +. i .   .
        . o .   .           +-----+                  o   .   .
      .   n   .   .                                . n .   .

                                 Figure 1.

   General familiarity with the TRILL base protocol standard [RFC6325]
   and with Fine Grained Labels [RFCfgl] is assumed in this document.

1.2 Terminology

   The same terminology and acronyms are used in this document as in
   [RFC6325] and [RFCfgl] with the following additions.

      "Cut set" is defined in Section 1.1.

      "Data Label" means VLAN or FGL.

      "FGL" means Fine Grained Label [RFCfgl].

"Internal RBridges" are TRILL switches other than the "cut set".

      "label" means "Data Label" unless the context requires some other

      RBridge - an alternative name for a TRILL Switch.

      TRILL Switch - a device which implements the TRILL protocol.

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   document are to be interpreted as described in [RFC2119].

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2. Internal and Cut Set Configuration and Mappings

   Internal RBridges will not be aware that label and priority mapping
   is going on and require no configuration.  They will behave exactly
   as they would without mapping.  The only evidence they might have of
   label or priority mapping is the existence of an optional
   informational sub-TLV that a cut set RBridge, RB1, MAY include in its
   LSP, listing the mappings that RB1 is configured to be performing.
   Internal RBridges will ignore this information field. It is there for
   detection of misconfiguration.

   Cut set RBridges are configured as follows:

   If label A in region "East" is to be translated into label B in
   region "West", each cut set RBridge MUST be configured, for every
   port, as to whether that port is in East or West, and configured with
   label mappings, such as:

                    "East/Label A -----> West/Label B"

   That mapping means that a TRILL Data frame with an Data Label of A
   received by RB1 on a port configured to be in East and forwarded to a
   port configured to be in West is forwarded with the Data Label
   changed to B. It is possible to configure asymmetric mappings;
   however, such asymmetric mappings have negative consequences as
   described below. For the above mapping to be symmetrically
   configured, it would be necessary to also configure the cut set
   RBridge in question so that frames arriving from West in Data Label B
   would also be mapped to label A if they are destined for East, that

                    "West/Label B <-----> East/Label A"

                                 Figure 2.

   Data Labels A and B may be both VLAN IDs, both FGLs, or one a VLAN ID
   and one an FGL.

   Mappings of the inner priority of TRILL Data packets are configured
   in the same way.

   The requirement that every port of a cut set RBridge MUST be
   configured as to which region it is in applies even to ports for a
   link between cut set RBridges such as the link between RB2 and RB3 in
   Figure 1. The TRILL Data packets on that link have a normal Data
   Label and priority. In a campus with multiple regions, a label and
   priority are, in general, meaningless unless you know the region in
   which they occurs. So some specific region must be chosen for such a

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   All cut set RBridges between a pair of regions SHOULD be configured
   similarly if, as is normally the case, it is desired that the mapping
   of a TRILL Data packet going between those regions will be
   independent of which cut set RBridge the packet traverses.

   The default Data Label and priority mapping is the mapping that
   leaves labels and priorities unchanged. If a mapping has been
   specified for both the label and priority of a frame, both mappings
   are applied.

2.1 Multiple Crossings

   Under some circumstances, a TRILL Data packet could pass through cut
   set RBridges between a pair of regions more than once and thus have
   its Data Label and priority mapped more than one. This is true of
   both known unicast and multi-destination packets. For example, in
   Figure 3, if the link between RBwest1 and RBwest2 fails, then the
   shortest path from RBwest1 to RBwest2 may be through RBcut1, RBeast1,
   and RBcut2. In addition, multi-destination packets are sent via a
   distribution tree which might constrain such packets going between
   RBwest1 and RBwest2 to be routed through RBeast1.

                |                                 |
             +--+------+      +--------+          |
          ---+ RBwest1 +------+ RBcut1 +-------+  |  +---
             +-+---+---+      +--------+       |  |  |
               |   |                         +-+--+--+-+
            ---+   |                         | RBeast1 +---
                   |                         +-+--+--+-+
             +-----+---+      +--------+       |  |  |
          ---+ RBwest2 +------+ RBcut2 +-------+  |  +---
             +--+------+      +--------+          |
                |                                 |

                                    Figure 3.

   If all of the mappings at RBcut1 and RBcut2 are symmetric then the
   label and/or priority of such packets going from west to west via
   east might get mapped twice but the second mapping would restore them
   to their original value. Symmetric means, for example, that if RB1 is
   translating from "label A" to "label B" when forwarding from East to
   West, it will translate "label B" to "label A" when forwarding from
   West to East (see Figure 2).

   However, assume that RBcut1 and RBcut2 are configured with asymmetric
   mappings. Then multiple cut set transit may cause problems. For

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INTERNET-DRAFT                         TRILL: Label and Priority Regions

   example, if label A in west is mapped to label B in east and label B
   in east is mapped to label C in west, then the above scenario could
   lead to frames in label A from west to west being unexpectedly mapped
   to label C causing connectivity between labels A and C in west and
   failure to deliver the frame as intended. Similar considerations
   apply to priority mappings.  The probability of such situations can
   be minimized by providing rich interconnectivity within each region
   and increasing the cost of links to cut set RBridges, so that packets
   internal to a regions will be routed internally to that region except
   in cases of low probability multiple failures. It is generally safest
   to configure symmetric mappings.

2.2 Native Frame Considerations

   If the processing model described in [RFC6325] is followed, then no
   special handling is necessary for the case where a cut set RBridge
   receives or transmits a native data frame, that is, where the cut set
   RBridge is also an ingress or egress RBridge. In particular, the
   processing model used in [RFC6325] provides that an ingressed native
   frame is always encapsulated, even if it is to be immediately
   decapsulated and delivered out a different port of the same RBridge
   in native form. (Of course, implementers are free to handle this in
   other ways provided the external behavior is the same.) Thus,
   following this processing model, no changes are needed in an
   implementation model of Data Label and priority mapping described
   entirely in terms of the manipulation of the Data Label and priority
   of TRILL data packets.

   On the other hand, if there are no internal RBridges in a region, say
   region West in Figure 1, then all frames will arrive from that region
   at the cut set RBridges as native frames and all native frames sent
   into that region will be unencapsulated. Under these limited
   circumstances, traditional bridge port VLAN and priority mapping
   could work to assist in performing the inter-regional mappings
   described in this document.

2.3 More than Two Regions

   A TRILL campus may have more than two regions. An RBridge is in the
   cut set between any pair of such regions if and only if it has at
   least one port in each of the regions. There may be pairs of regions
   that, because of other intervening regions, have no cut set RBridges
   connected to them both.

   Every RBridge that is in any cut set MUST have every port configured
   as to which region that port is in.  Every RBridge port on a link

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INTERNET-DRAFT                         TRILL: Label and Priority Regions

   between two or more cut set RBridges, such as that shown between RB2
   and RB3 in Figure 1, SHOULD be configured to be in the same region.
   The mappings performed on TRILL Data packets transiting a cut set
   RBridge that has ports in three or more regions depend only on the
   region of that packet's input and output ports and are unaffected by
   what region any other ports of that RBridge might be connected to.

   It is RECOMMENDED that not only should any mappings be symmetric at
   every cut set RBridge in a campus that implements the label and
   priority mapping feature but that all cut set RBridges in the campus
   should be configured so as to be transitively symmetric and similar.
   That is, the mapping of the label and priority in a packet going from
   region A to region Z should be independent of the path that frame
   follows in the campus and symmetric with the mapping to which any
   packet going from region Z to region A would be subjected.

2.4 Mapping Implementation

   If RB1 is configured to believe port X is in "East" and port Y is in
   "West", and RB1 is configured such that "East/Label A ---->
   West/Label B", then when RB1 forwards data packets from port X to
   port Y, if the received packet from port X has Data Label A, then RB1
   changes that from label A to label B before it forwards out port Y.
   Similarly, if priority mapping has been configured, the inner
   priority field is mapped. In the case of FGL, the first priority, the
   priority which affects the packets propagation through the campus, is
   mapped. The second priority field, which is restored on egress, is

   This mapping is performed whether RB1 is the appointed forwarder on
   port X for VLAN A and the frame arrives unencapsulated, or whether
   the traffic has arrived already in TRILL Data packet form.  Likewise,
   RB1 performs the same label and priority mapping, depending on input
   and output port, whether the packet is to a known unicast address or
   is multi-destination.

   RBridges may implement campus region label and priority mapping in
   any way desired so long as the externally visible behavior matches
   this specification. Two example models of processing, forwarding-
   oriented and port-oriented, are described below.

      In the forwarding-oriented model, label and priority mappings
      occur once as part of the inter-port forwarding process within a
      TRILL switch and depend on the ordered pair { input-port-region,
      output-port-region }.

      In the port-oriented model, label and priority mappings occur once
      or twice associated with input and/or output port. For example,

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INTERNET-DRAFT                         TRILL: Label and Priority Regions

      for Data Labels, each input port of a cut set RBridge could (after
      encapsulation in the case of a native frame) map the Data Label to
      a value in an RBridge specific generic label space, with the
      mapping dependent only on the region to which that input port was
      assigned. Then, the output port through which the packet was sent
      would map from that generic label space to a specific Data Label
      with the mapping depending only on the region to which the output
      port was assigned. Either mapping could be the mapping that did
      not change the label.  A similar model could be used for priority
      mapping with similar considerations.

   These two processing models are logically interchangeable.

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INTERNET-DRAFT                         TRILL: Label and Priority Regions

3. End Node Address Learning Between Regions

   TRILL switches by default learn end node MAC addresses and labels
   from the observation of ingressed native frames and the decapsulation
   of native frames at egress, as described in [RFC6325] and [RFCfgl].
   This process requires no modification at internal RBridges to
   accommodate Data Label mapping as described herein as the label will
   be appropriate for the region where it is observed.

   For a cut set RBridge, each port is specified to be in a particular
   region. For such an RBridge, the Data Label portion of the addresses
   learned at a port providing direct end station service will be that
   label in the region to which the cut set RBridge has assigned the
   port. Care must be taken within a cut set RBridge when using such
   learned information. For example, if a native frame is received in
   label X from region Y destined for MAC address Z, then address Z can
   be looked up in the address information learned for other regions
   only after applying any mapping for label X to that region.

   TRILL also allows RBridges to optionally advertise attached end
   nodes.  This end node advertisement uses the TRILL ESADI (End System
   Address Distribution Information) protocol [RFCesadi]. Because TRILL
   ESADI packets do not include the label to which they are applicable
   anywhere except in their Data Label and ESADI packets are forwarded
   just like ordinary multi-destination TRILL Data packets, the label
   mapping described above works for ESADI learning. Because of this,
   any future ESADI extensions MUST NOT require label fields inside the
   ESADI packet payload.

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4. Cut Set Attraction of Labels and Multicast

   The above described mechanisms are all that is required for Data
   Label and priority mapping of frames sent to known unicast addresses.
   However, to correctly handle multi-destination traffic, additional
   steps are required. In particular, unless cut-set RBridges take
   additional action, multi-destination packets that they need to
   forward from one region to another might not reach the cut set
   RBridge due to the optional pruning of distribution trees by internal

   If RB1 is configured to translate Data Label A in East to label B in
   West, then RB1 MUST report, in its LSP, that it is interested in both
   label A and label B data, even if RB1 does not actually have a port
   for which it is ingressing to or egressing from either either label A
   or label B.  If it did not do this, a multi-destination frame in
   label A in East might be pruned before reaching RB1 and not mapped to
   label B and forwarded to West as it should.

   If RB1 is configured to translate label A in East to label B in West,
   then RB1 MUST take steps to ensure that a multicast packet for group
   G in label A will not be filtered inside the East region.  To solve
   this problem RB1 MUST report that it is connected in label A to an
   IPv4 and IPv6 multicast router so it will get all multi-cast traffic
   in label A and can forward appropriate multicast frames mapped to
   label B. While this increases traffic to cut set RBridges, it does so
   to an extent no worse that an RBridge connected to an actual Layer 3
   multicast router or routers.

   Because all the regions operate as a single TRILL campus with a
   unified IS-IS link state database, it is not possible to confine the
   above required announcements to a subset of the RBridges in the

   Cut set RBridges and the links connecting them to the rest of the
   network should be appropriately engineered for any additional traffic
   load these requirements impose.

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5. Advertisement of Label and Priority Mappings

   To help detect misconfiguration, a cut set RBridge RB1 MAY advertise
   its label and priority mappings in its LSP. To enable this, a 16-bit
   unsigned ID is assigned to each of the regions by manual
   configuration.  All cut set RBridges SHOULD be configured with the
   same IDs for the regions but means of accomplishing this are outside
   of the scope of this document.  So, in our example Figure 1, if
   "East" is "1" and "West" is "2", and Data Label A in East is mapped
   to Data Label B in West, and vice versa to be symmetric, the LSP
   would report a set of mappings, including:

                       {label: (1:A,2:B), (2:B,1:A)}

   Data Labels must include the type such as VLAN-42 or FGL-1234.

   Illegal VLAN IDs (VLAN-0 or VLAN-4095 (0xFFF)) should never appear as
   a Data Label in an LSP advertising label mappings but if they do, the
   mapping where they appear are ignored for consistency checking.

   Priority mappings can be similalry advertised.

   The actual encoding of this information and the Type or sub-Type
   values for any new TLV or sub-TLV data elements are specified in a
   separate document

6. IANA Considerations

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

7. Security Considerations

   See [RFC6325] for general TRILL Security Considerations and [RFCfgl]
   for Fine Grained Label Security Considerations

   If cut set RBridges have misconfigured Data Label mappings, labels
   may be inadvertently partitioned or inadvertently merged and frames
   may be delivered in the wrong label, which could violate security
   policies.  However, misconfiguration of label or priority mappings
   cannot cause loops because mappings of labels and/or priority have no
   effect on unicast frame routing, shortest path calculations,
   distribution tree construction or selection, or the like.

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8. Normative References

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

   [RFC6325] - Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and A.
         Ghanwani, "Routing Bridges (RBridges): Base Protocol
         Specification", RFC 6325, July 2011.

   [RFCfgl] - D. Eastlake, M. Zhang, P. Agarwal, R. Perlman, D. Dutt,
         "TRILL (Transparent Interconnection of Lots of Links): Fine-
         Grained Labeling", draft-ietf-trill-fine-labeling, in RFC
         Editor's queue.

9. Informative References

   [RFC6327bis] - Eastlake, D., R. Perlman, A. Ghanwani, H. Yang, V.
         Manral, "Routing Bridges (RBridges): Adjacency", draft-ietf-
         trill-rfc6327bis, work in progress.

   [RFCclear] - D. Eastlake, M. Zhang, A. Ghanwani, V. Manral, A.
         Banerjee, draft-ietf-trill-clear-correct, in RFC Editor's

   [RFCesadi] - H. Zhai, F. Hu, R. Perlman, D. Eastlake, O. Stokes,
         "TRILL: ESADI Protocol", draft-ietf-trill-esadi, work in

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Appendix Z: Change Summary

   RFC Editor Note: Please delete this Appendix Z on publication.

Changes from -00 to -01

   1. Because RBridges cannot tell what cloud other RBridges are in,
      drop the "optimized" option for advertising multicast listeners
      and require the advertisement of multicast router connectivity.

   2. Specify that the cloud connectivity must be specified for all cut
      set RBridges and that cloud IDs are manually configured and are 16

   3. Expand rules for VLAN ID mapping/handling at a cut set RBridge so
      as to drop frames that are for a VLAN ID to which another VLAN ID
      is being mapped. (See Section 3.)

   4. Add mention of "VLAN ID translation", the 802.1 name for VLAN

   5. Minor editing changes.

Changes from -01 to -02

   1. Remove previous confused text about VLAN mapping (point 3 in
      changes from -00 to -01).

   2. Add text allowing mapping to zero to indicate frames should be
      dropped. Add text and diagram explaining that this can lead to
      VLAN partition.

   3. Add normative reference to draft-ietf-isis-layer2.

   4. Minor editing changes.

Changes from -02 to -03

   This was a substantial re-write of the draft but there was no
   fundamental conceptual change in the mapping mechanism.

   1. Replace "cloud" with "region".

   2. Introductory material was re-written to primarily reference

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      RBridge campuses and reduce references to 802.1 bridges.

   3. Mapping of priority was added to mapping of VLANs.

   4. Two different models are now described for implementation of
      mappings, one in the forwarding mechanism as before and one
      associated with the RBridge ports.

   5. Add the specification of the TRILL GenApp TLV. Switch to using
      TRILL GenApp TLV sub-TLVs to advertise VLAN and priority mappings.
      Add specification of those sub-TLVs. Remove reference to draft-

   6. The IANA considerations section calls for the allocation of a
      GenApp TLV code for TRILL and provides for sub-TLVs under that
      code where the LSP advertisement of VLAN and priority mappings was
      moved.  Set up IANA registry for TRILL GenApp sub-TLVs.

   7. Numerous minor editing changes.

Changes from -03 to -04

   1. Because distribution trees for multi-destination frames may cause
      frames to cross region boundaries multiple times even to get
      between RBridges within a single regions, remove facilities for
      dropping frames at region boundaries.

   2. Due to questions about the timing of the approval of the IS-IS
      GenApp draft, move VLAN/priority mapping informational
      advertisement code points and data structures to a separate draft.

   3. Numerous minor editing changes.

Changes from -04 to -05

   Increment version and update dates. Update author info. One or two
   minor editorial changes.

Changes from -05 to -06

   Update draft reference to [RFC6325]. Increment version and update

R. Perlman, et al.                                             [Page 16]

INTERNET-DRAFT                         TRILL: Label and Priority Regions

Changes from -06 to -07

   Update author information, increment version, and update dates.

Changes from -07 to -08

   Minor editorial changes, update author information, increment
   version, and update dates.

Changes from -08 to -09

   Extend to cover Fine Grained Labeling.

   Update author information, increment version, and update dates.

Changes from -09 to -10

   Update RFC 6327 reference to draft-ietf-trill-rfc6327bis.

   Editorial changes, increment version, and update dates.

R. Perlman, et al.                                             [Page 17]

INTERNET-DRAFT                         TRILL: Label and Priority Regions

Authors' Addresses

   Radia Perlman
   Intel Labs
   2200 Mission College Blvd.
   Santa Clara, CA 95054-1549 USA

   Phone: +1-408-765-8080
   Email: Radia@alum.mit.edu

   Anil Rijhsinghani
   HP Networking
   350 Campus Drive
   Marlboro, MA 01752-3082 USA

   Phone: +1-508-323-1251
   Email: anil.rijhsinghani@hp.com

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

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

   Ayan Banerjee
   Insieme Networks
   210 West Tasman Drive
   San Jose, CA 95134 USA

   Email: ayabaner@gmail.com

   Dinesh G. Dutt
   Cumulus Networks
   1089 West Evelyn Avenue
   Sunnyvale, CA 94086 USA

   Email: ddutt.ietf@hobbesdutt.com

R. Perlman, et al.                                             [Page 18]

INTERNET-DRAFT                         TRILL: Label and Priority Regions

Copyright, Disclaimer, and Additional IPR Provisions

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R. Perlman, et al.                                             [Page 19]

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