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Versions: 00 01 02 03 04 05 06 draft-ietf-trill-directory-assist-mechanisms

INTERNET-DRAFT                                              Linda Dunbar
Intended status: Proposed Standard                       Donald Eastlake
                                                                  Huawei
                                                           Radia Perlman
                                                                   Intel
                                                          Igor Gashinsky
                                                                   Yahoo
                                                               Yizhou Li
                                                                  Huawei
Expires: August 24, 2012                               February 25, 2013


                 TRILL: Directory Assistance Mechanisms
        <draft-dunbar-trill-scheme-for-directory-assist-04.txt>



Abstract
   This document describes optional mechanisms for using directory
   server(s) to assist TRILL (Transparent Interconnection of Lots of
   Links) edge switches in reducing multi-destination traffic,
   particularly ARP/ND and unknown unicast flooding.



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-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

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








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Table of Contents

      1. Introduction............................................3
      1.1 Terminology............................................3
      1.2 Circumstances Causing Directory Use....................4

      2. Push Model Directory Assistance Mechanisms..............5
      2.1 Requesting Push Service................................5
      2.2 Actions by Push Directory Servers......................5
      2.3 Additional Push Details................................6

      3. Pull Model Directory Assistance Mechanisms..............8
      3.1 Pull Directory Request Format..........................8
      3.2 Pull Directory Response Format........................10
      3.3 Pull Directory Hosted on an End Station...............12
      3.4 Pull Directory Request Errors.........................14
      3.5 Cache Consistency.....................................15
      3.6 Additional Pull Details...............................17

      4. Directory Use Strategies and Push-Pull Hybrids.........18
      4.1 Strategy Configuration................................18

      5. The Interface Addresses APPsub-TLV.....................21
      5.1 Format of the Interface Addresses APPsub-TLV..........21
      5.2 IA-APPsub-TLV sub-sub-TLVs............................24
      5.2.1 AFN Size sub-sub-TLV................................25
      5.2.2 Fixed Address sub-sub-TLV...........................26
      5.2.3 Data Label sub-sub-TLV..............................26
      5.2.4 Topology sub-sub-TLV................................27

      6. Security Considerations................................28

      7. IANA Considerations....................................29
      7.1 ESADI-Parameter Bits..................................29
      7.2 RBridge Channel Protocol Number.......................29
      7.3 Pull Directory and No Data Bits.......................29
      7.4 Additional AFN Number Allocation......................30
      7.5 IA APPsub-TLV Sub-Sub-TLVs SubRegistry................30

      8. Acknowledgments........................................32

      9. References.............................................33
      9.1 Normative References..................................33
      9.2 Informational References..............................34








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1. Introduction

   [DirectoryFramework] describes a high level framework for using
   directory servers to assist TRILL [RFC6325] edge nodes to reduce
   multi-destination ARP/ND and unknown unicast flooding traffic.
   Because multi-destination traffic becomes an increasing burden as a
   network scales, reducing ARP/ND and unknown unicast flooding improves
   TRILL network scalability. This document describes optional specific
   mechanisms for directory servers to assist TRILL edge nodes.

   The information held by the directories is address mapping
   information.  Most commonly, what MAC address corresponds to an IP
   address within a Data Label (VLAN or FGL (Fine Grained Label
   [RFCfgl])) and what egress TRILL switch (RBridge) that MAC address is
   attached to. But it could be what IP address corresponds to a MAC
   address or possibly other mappings. In the data center environment,
   it is common for orchestration software to know and control where all
   the IP addresses, MAC address, and VLANs/tenants are. Thus such
   orchestration software is appropriate for providing the directory
   function or for supplying the Directory(s) with information they
   need.

   Directory services can be offered in a Push or Pull mode. Push mode,
   in which a directory server pushes information to RBridges indicating
   interest, is specified in Section 2. Pull mode, in which an RBridge
   queries a server for the information it wants, is specified in
   Section 3. Hybrid Push/Pull modes of operation are discussed in
   Section 4.

   The mechanisms used to keep the mappings held by different
   Directories synchronized is beyond the scope of this document.



1.1 Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC-2119 [RFC2119].

   The terminology and acronyms of [RFC6325] are used herein along with
   the following additional acronyms and terms:

   Data Label: VLAN or FGL.

   FGL:  Fine Grained Label [RFCfgl].

   Host: Application running on a physical server or a virtual machine.
         A host must have a MAC address and usually has at least one IP
         address.


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   IP:   Internet Protocol. In this document, IP includes both IPv4 and
         IPv6.

   RBridge: An alternative name for a TRILL switch.

   TRILL switch: An alternative name for an RBridge.



1.2 Circumstances Causing Directory Use

   While an RBridge can consult Directory information whenever it wants,
   by searching through information that has been pushed to it or
   requesting information from a pull directory, the following are
   expected to be the most common circumstances leading to directory
   use. All of these involve cases of ingressing a native frame.

      o  Ingressing an frame with an unknown unicast destination MAC.
         The mapping from the destination MAC and Data Label to its
         egress RBridge of attachment is needed to ingress the frame as
         unicast. If the egress RBridge is unknown, the frame must be
         dropped or ingressed as a multi-destination frame and flooded
         to all edge RBridges for its Data Label.

      o  Ingressing an ARP [RFC826]. ...TBD

      o  Ingressing a ND [RFC903]. ...TBD... Secure Neighbor Discovery
         messages [] will, in general, have to be sent to the neighbor
         intended so that neighbor can sign the answer; however,
         directory information can be used to unicast the ND packet
         rather than multicasting it.

      o  Ingressing a RARP [RFC4861]. ...TBD



















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2. Push Model Directory Assistance Mechanisms

   In the Push Model, Push Directory servers push down the mapping
   information for the various addresses of end stations in some Data
   Label.  A Push Directory advertises whether or not it believes it is
   pushing complete mapping information for a Data Label. The Push Model
   uses the [ESADI] protocol.

   With this model, it is RECOMMENDED that complete address mapping
   information for a Data Label be pushed and that a participating
   RBridge simply drop a data packet, instead of flooding the packet, if
   the destination unicast MAC address is in a category being pushed and
   can't be found in the mapping information available. This will
   minimize flooding of packets due to errors or inconsistencies but is
   not practical if directories have incomplete information.



2.1 Requesting Push Service

   In the Push Model, it is necessary to have a way for an RBridge to
   request information from the directory server(s).  RBridges simply
   use the ESADI protocol mechanism to announce, in the IS-IS link state
   database, all the Data Labels for which they are participating in
   [ESADI]. They are then pushed the mapping information for all such
   Data Labels being served by a Push Directory server.



2.2 Actions by Push Directory Servers

   Push Directory servers advertise their availability to push the
   mapping information for a particular Data Label to ESADI participants
   for that Data Label by turning on a flag bit in their ESADI Parameter
   APPsub-TLV [ESADI] (see Section 7.1).

   Each Push Directory server MUST participate in ESADI for the Data
   Labels for which it can push mappings and set the PD bit in their
   ESADI-Parameters APPsub-TLV for that Data Label.

   For robustness, it is useful to have more than one copy of the data
   being pushed. Each RBridge that is a Push Directory server is
   configured with a number in the range 1 to 8, which defaults to 2, as
   to the number of copies it believes should be pushed. Each Push
   Directory server also has a priority that is its 6-byte IS-IS System
   ID treated as an unsigned integer where larger magnitude means higher
   priority.

   For each Data Label it can serve, each Push Directory RBridge server
   orders the Push Directory servers that it can see as data reachable


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   [RFCclear] in the ESADI link state database for that Data Label and
   determines its position in that order. If a Push Directory server
   believes that N copies of the mappings for a Data Label should be
   pushed and finds that it is first in priority or, more generally, not
   lower than Nth in priority, it is Active. If it finds that it is
   N+1st or lower in priority, it is Passive.

   For example, assume four Push Directory servers for Data Label X:
   server A with priority 123 configured to believe there should be 2
   copies pushed; server B, priority 88, 1 copy; server C, priority 40,
   3 copies; and server D, priority 7, 2 copies. Server A, seeing that
   is highest priority, is Active. Server B, seeing that it is 2nd
   highest priority and believing that only 1 copy should be pushed, is
   Passive. Server C sees that it is 3rd highest priority and believes 3
   copies should be pushed, so it is Active. And server D sees it is 4th
   highest priority and, believing that only 2 copies should be pushed,
   is Passive.

   If a Push Directory server is Active for Data Label X, it includes
   the Data Label X directory mappings it has in its ESADI-LSP for Data
   Label X and updates that information as the mappings it knows change.
   If the Push Directory server is configured to believe it has complete
   mapping information for Data Label X then, after it has actually
   transmitted all of its ESADI-LSPs for X it waits its CSNP time (see
   Section 6.1 of [ESADI]), and then updates its ESADI-Parameters
   APPsub-TLV to set the Complete Push (CP) bit to one. It then
   maintains the CP bit as one as long as it is Active.

   If a Push Directory server is Passive for Data Label X, it removes or
   continues to leave out all Data Label X directory mappings it holds
   from its ESADI-LSP for Data Label X. However, if it was Active and
   was advertising the CP bit as one in its ESADI-Parameters APPsub-TLV,
   it first updates the CP bit to zero and sends its updated ESADI-LSP
   fragment zero and then waits its CSNP time before withdrawing all its
   directory mapping information.



2.3 Additional Push Details

   Push Directory mappings can be distinguished for any other data
   distributed through ESADI because mappings are distributed only with
   the Interface Addresses APPsub-TLV specified in Section 5 and are
   flagged as being Push Directory data.

   RBridges, whether or not they are a Push Directory server, MAY
   advertise any locally learned MAC attachment information in ESADI
   using the Reachable MAC Addresses TLV [RFC6165]. However, if a Data
   Label is being served by complete Push Directory servers, advertising
   such locally learned MAC attachment would generally not be done as it


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   should not add anything and would just waste bandwidth and ESADI link
   state space. An exception would be when an RBridge learns local MAC
   connectivity and that information appears to be missing from the
   directory mapping. In that case, it SHOULD advertise the missing
   information unless configured not to.

   Because a Push Directory server may need to advertise interest in
   Data Labels even though it does not want to received user data in
   those Data Labels, the No Data flag bit is provided as discussed in
   Section 7.3.

   If an RBridge notices that a Push Directory server is no longer data
   reachable [RFCclear], it MUST ignore any Push Directory data from
   that server because it is no longer being updated and may be stale.

   There may be transient conflicts between mapping information from
   different Push Directory servers or conflicts between locally learned
   information and information received from a Push Directory server. In
   case of such conflicts, information with a higher confidence value is
   preferred over information with a lower confidence. In case of equal
   confidence, Push Directory information is preferred to locally
   learned information and if information from Push Directory servers
   conflicts, the information from the higher priority Push Directory
   server is preferred.




























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3. Pull Model Directory Assistance Mechanisms

   In the Pull Model, an RBridge pulls mapping information from an
   appropriate Directory Server when needed.

   Pull Directory servers for a particular Data Label X are located by
   looking in the main TRILL IS-IS link state database for RBridges that
   advertise themselves by having the Pull Directory flag on in their
   Interested VLANs or Interested Labels sub-TLV [rfc6326bis] for X. If
   multiple RBridges indicate that they are Pull Directory Servers for a
   particular Data Label a pull request can be sent to any of them that
   is data reachable but it is RECOMMENDED that pull requests be sent to
   server that is least cost from the requesting RBridge.

   Pull Directory requests are sent by enclosing them in an RBridge
   Channel [Channel] message using the Pull Directory channel protocol
   number (see Section 7.2).  Responses are returned in an RBridge
   Channel message using the same channel protocol number.

   The requests to Pull Directory Servers are derived from normal ARP
   [RFC826], ND [RFC4861], RARP [RFC903] messages or data frames with
   unknown unicast destination MAC addresses intercepted by the RBridge
   when they would otherwise be ingressed.  Pull Directory responses
   include an amount of time for which the response should be considered
   valid. This includes negative responses that indicate no data is
   available or the requester is administratively prohibited from
   receiving the data or the like. Thus both positive responses with
   data and negative responses can be cached and used for immediate
   response to ARP, ND, RARP, or unknown destination MAC frames, until
   they expire.  If information previously pulled is about to expire, an
   RBridge MAY try to refresh it by issued a new pull request but, to
   avoid unnecessary requests, SHOULD NOT do so if it has not been
   recently used.



3.1 Pull Directory Request Format

   A Pull Directory request is sent as the Channel Protocol specific
   content of an inter-RBridge Channel message TRILL Data packet. The
   Data Label in the packet is the Data Label in which the address is
   being looked up. The priority of the channel message is a mapping of
   the priority frame being ingressed that caused the request with the
   default mapping depending, per Data Label, on the strategy (see
   Section 4). The Channel Protocol specific data is formatted as
   follows:






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       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   V   |Q|    RESV     | Count |              RESV             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Sequence Number                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | QUERY 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      | QUERY 2
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      | ...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      | QUERY K
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...

      V: Version of the Pull Directory protocol as an unsigned integer.
         Version zero is specified in this document.

      Q: Query/Response Bit. MUST be one for a query.

      RESV: Reserved bits. MUST be sent as zero and ignored on receipt.

      Count: Number of queries present.

      Sequence Number: An opaque 32-bit quantity set by the sending
         RBridge, returned in any responses, and used to match up
         responses with queries.

      QUERY: Each Query record within a Pull Directory request message
         is formatted as follows:

           0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15
         +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
         |         SIZE          |         RESV          |
         +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
         |                      AFN                      |
         +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
         |                  Address ...
         +--+--+--+--+--+--+--+--+--+--+--...

         SIZE: Size of the query data in bytes. This is the length of
            the Address plus 4.

         RESV: A reserved byte. MUST be sent as zero and ignored on
            receipt.

         AFN: Address Family Number of the Address.

         Address: This is the address for which the query is asking for


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            mappings. Typically it would be either (1) a MAC address, in
            which case the querying RBridge is interested in the RBridge
            by which that MAC address is reachable, or (2) an IP
            address, in which case the querying RBridge is interested in
            the corresponding MAC address and the RBridge by which that
            MAC address is reachable.

   A query count of zero is explicitly allowed, for the purpose of
   pinging a Pull Directory server to see if it is responding to
   requests. It results in a response message that also has a count of
   zero.

   If no response is received to a Pull Directory request within a
   configurable timeout, the request should be re-transmitted with the
   same Sequence Number up to a configurable number of times that
   defaults to three. If there are multiple queries in a request,
   responses can be received to various subsets of these queries by the
   timeout. In that case, the remaining unanswered queries should be re-
   sent in a new query with a new sequence number.  If an RBridge is not
   capable of handling partial responses to requests with multiple
   queries, it MUST NOT sent a request with more than one query in it.



3.2 Pull Directory Response Format

   Pull Directory responses are sent as the Channel Protocol specific
   content of inter-RBridge Channel message TRILL Data packets.
   Responses are sent with the same Data Label and priority as the
   request to which they correspond except that the response priority is
   limited. This priority limit is configurable at a per RBridge level
   and defaults to priority 6. The Channel protocol specific data format
   is as follows:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   V   |Q|U|F|P|N| RESV| Count |      ERR      |  subERR       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Sequence Number                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | RESPONSE 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      | RESPONSE 2
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      | ...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      | RESPONSE K
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...



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      V: Version of the Pull Directory protocol. Version zero is
         specified in this document.

      Q: Query/Response Bit. MUST be zero for a response.

      U: Unsolicited Bit. MUST be zero for a response to a query and one
         for an unsolicited "response" sent to maintain cache
         consistency (see Section 3.5).

      F: The Flood bit. If zero, the reply is to be unicast to the
         provided Nickname. If U=1, F=1 is used to flood messages for
         certain unsolicited cache consistency maintenance messages from
         an end station Pull Directory server as discussed in Section
         3.5. If U=0, F is ignored.

         P, N: Flags used in connection with certain flooded unsolicited
         cache consistency maintenance messages. Ignored if U is zero.
         If the P bit is a one, the solicited response message relates
         to cached positive response information. If the N bit is a one,
         the unsolicited messages related to cached negative
         information. See Section 3.5.

      RESV: Reserved bits. MUST be sent as zero and ignored on receipt.

      Count: Count is the number of responses present in the particular
         reponse message.

      ERR, subERR: A two part error code. See Section 3.4.

      Sequence Number: An opaque 32-bit quantity set by the requesting
         RBridge and copied by the Pull Directory into all responses to
         the query. For an unsolicited "response", the contents are
         unspecified.

      RESPONSE: Each response record within a Pull Directory response
         message is formatted as follows:

           0  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15
         +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
         |         SIZE          |   RESV    |   Index   |
         +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
         |                   Lifetime                    |
         +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
         |                Response Data ...
         +--+--+--+--+--+--+--+--+--+--+--...

         SIZE: Size of the response data in bytes plus 4.

         RESV: Four reserved bits that MUST be sent as zero and ignored
            on receipt.


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         Index: The relative index of the query in the request message
            to which this response corresponds. The index will always be
            one for request messages containing a single query. The
            index will always be zero for unsolicited "response"
            messages.

         Lifetime: The length of time for which the response should be
            considered valid in seconds.

         Response Data: There are two types of response data. If the ERR
            field is non-zero, the response data is a copy of the query
            data, that is, an AFN followed by an address. If the ERR
            field is zero, the response data is the contents of an
            Interface Addresses APPsub-TLV (see Section 5) without the
            usual TRILL GENINFO TLV type and length and without the
            usual IA APPsub-TLV type and length before it.

   Multiple response records can appear in a response message with the
   same index if the answer to a query consists of multiple Interface
   Address APPsub-TLV contents. This would be necessary if, for example,
   a MAC address within a Data Label appears to be reachable by multiple
   RBridges.

   All response records to any particular query record MUST occur in the
   same response message. If a Pull Directory holds more mappings for a
   queried address than will fit into one response message, it selects
   which to include by some method outside the scope of this document.

   See Section 3.4 for a discussion of how errors are handled.



3.3 Pull Directory Hosted on an End Station

   Optionally, a Pull Directory actually hosted on an end station MAY be
   supported. In that case, when the RBridge advertising itself as a
   Pull Directory server receives a query, it modifies the inter-RBridge
   Channel message received into a native RBridge Channel message and
   forwards it to that end station. Later, when it receives one or more
   responses from that end station by native RBridge Channel messages,
   it modifies them into inter-RBridge Channel messages and forwards
   them to the source RBridge of the query.

   The native RBridge Channel Pull Directory messages use the same
   Channel protocol number as do the inter-RBridge Pull Directory
   Channel messages. The native messages MUST be sent with an Outer.VLAN
   tag which give the priority of each message which is the priority of
   the original inter-RBridge request packet. The Outer.VLAN ID used is
   the Designated VLAN on the link.



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   The native RBridge Channel message protocol dependent data for a Pull
   Directory query is formatted as follows:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   V   |Q|    RESV     | Count |           Nickname            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Data Label ... (4 or 8 bytes)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Sequence Number                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | QUERY 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      | QUERY 2
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      | ...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      | QUERY K
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...

      Data Label: The Data Label of the original inter-RBridge Pull
         Directory Channel protocol messages that was mapped to this
         native channel message. The format is the same as it appears
         right after the Inner.MacSA of the original Channel message.

      Nickname: The nickname of the requesting RBridge.

      All other fields are as specified in Section 3.1.

   The native RBridge Channel message protocol specific content for a
   Pull Directory response is formatted as follows:

       0                   1                   2                   3
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   V   |Q|U|F|P|N| RESV| Count |      ERR      |  subERR       |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |           Nickname            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   Data Label ... (4 or 8 bytes)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                        Sequence Number                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | RESPONSE 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      | RESPONSE 2
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      | ...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...


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      | RESPONSE K
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...

      Data Label: The Data Label to which the response applies. The
         format is the same as it appears right after the Inner.MacSA in
         TRILL Data messages.

      Nickname: The nickname of the destination RBridge or, if F=1,
         ignored.

      All other fields are as specified in Section 3.2.



3.4 Pull Directory Request Errors

   An error response message is indicated by a non-zero ERR field.

   If there is an error that applies to the entire request message or
   its header, as indicated by the range of the value of the ERR field,
   then the query records in the request are just expanded with a zero
   Lifetime and the insertion of the Index field echoed back in the
   response records.

   If errors occur at the query level, they MUST be reported in a
   response message separate from the results of any successful queries.
   If multiple queries in a request have different errors, they MUST be
   reported in separate response messages. If multiple queries in a
   request have the same error, this error response MAY be reported in
   one response message.

   In an error response message, the query or queries being responded to
   appear, expanded by the Lifetime for which the server thinks the
   error might persist and with their Index inserted, as the response
   record.

   ERR values 1 through 63 are available for encoding request message
   level errors. ERR values 64 through 255 are available for encoding
   query level errors. the SubErr field is available for providing more
   detail on errors. The meaning of a SubErr field value depends on the
   value of the ERR field.











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         ERR    Meaning
         ---    -------
           0    (no error)

           1    Unknown V field value
           2    Request data too short
           3    Administratively prohibited
         4-31   (Available for allocation by Standards Action)

          32    Unknown AFN
          33    No mapping found
          34    Administratively prohibited
         35-255 (Available for allocation by Standards Action)

   More TBD...?



3.5 Cache Consistency

   Pull Directories MUST take action to minimize the amount of time that
   an RBridge will continue to use stale information from the Pull
   Directory.

   A Pull Directory server MUST maintain one of the following, in order
   of increasing specificity.

      1. An overall record per Data Label of when the last returned
         query data will expire at a requestor and when the last query
         record specific negative response will expire.

      2. For each unit of data (IA APPsub-TLV Address Set) held by the
         server and each address about which a negative response was
         sent, when the last expected response with that unit or
         negative response will expire at a requester.

      3. For each unit of data held by the server and each address about
         which a negative response was sent, a list of RBridges that
         were sent that unit as the response or sent a negative response
         to the address, with the expected time to expiration at each of
         them.

   A Pull Directory server may have a limit as to how many RBridges it
   can maintain expiry information for by method 3 above or how many
   data units or addresses it can maintain expiry information for by
   method 2. If such limits are exceeded, it MUST transition to a lower
   numbered strategy but, in all cases, MUST support, at a minimum,
   method 1.

   When data at a Pull Directory changes or is deleted or data is added


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   and there may be unexpired stale information at a querying RBridge,
   the Pull Directory MUST send an unsolicited message as discussed
   below.

   If method 1, the most crude method, is being followed, then when any
   information in a Data Label is changed or deleted or an additional
   administrative Pull Directory access restriction imposed, and there
   are outstanding cached positive query data response(s), an all-
   addresses flush positive message is flooded (multicast) within that
   Data Label. And if data is added or an administrative restriction is
   removed and there are outstanding cached negative responses, an all-
   addresses flush negative message is flooded. "All-addresses" is
   indicated by the Count in an unsolicited response being zero. On
   receiving an all-addresses flooded flush positive message from a Pull
   Directory server it has used, indicated by the U, F, and P bits being
   one, an RBridge discards all cached data responses it has for that
   Data Label. Similarly, on receiving an all addresses flush negative
   message, indicated by the U, F, and N bits being one, it discards all
   cached negative responses for that Data Label. A combined flush
   positive and negative can be flooded by having all of the U, F, P,
   and N bits set to one resulting in the discard of all positive and
   negative cached information for the Data Label.

   If method 2 is being followed, then an RBridge floods address
   specific update positive unsolicited responses when data which is
   cached by a querying RBridge is changed or deleted or an
   administrative restriction is added to such data and floods an
   address specific update negative unsolicited responses when such
   information is deleted or an administrative restriction is removed
   from such data. Such messages are similar to the method 1 flooded
   unsolicited flush messages. The U and F bits will be one and the
   message will be multicast. However that Count field will be non-zero
   and either the P or N bit, but not both, will be one. On receiving
   such as address specific message, if it is positive the addresses in
   the response records in the unsolicited response are compared to the
   addresses about which the recipient RBridge is holding cached
   positive information and, if they match, the cached information is
   updated and its remaining cache life set to the minimum of its
   previous value in the cache and the Lifetime value in the unsolicited
   response. In the case of a newly imposed administrative restriction,
   the Lifetime in the unsolicited response is set to zero so the cached
   information immediately expired. On receiving an address specific
   unsolicited negative response, the addresses in the response records
   in the unsolicited response are compared to the addresses about which
   the recipient RBridge is holding cached negative information and, if
   they match, the cached negative information is discarded.

   If method 3 is being followed, the same sort of messages are sent as
   with method 2 except they are not flooded but unicast only to the
   specific RBridges the server believes may be holding the cached


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   positive or negative information that may need updating.



3.6 Additional Pull Details

   If an RBridge notices that a Pull Directory server is no longer data
   reachable [RFCclear], it MUST discard all responses it is retaining
   from that server within one second as the RBridge can no longer
   receive cache consistency messages from the server.

   Because a Pull Directory server may need to advertise interest in
   Data Labels even though it does not want to received user data in
   those Data Labels, the No Data flag bit is provided as discussed in
   Section 7.3.





































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4. Directory Use Strategies and Push-Pull Hybrids

   For some edge nodes which have great number of Data Labels enabled,
   managing the MAC&Label <-> RBridgeEdge mapping for hosts under all
   those Data Labels can be a challenge. This is especially true for
   Data Center gateway nodes, which need to communicate with a majority
   of Data Labels if not all.

   For those RBridge Edge nodes, a hybrid model should be considered.
   That is the Push Model is used for some Data Labels, and the Pull
   Model is used for other Data Labels. It is the network operator's
   decision by configuration as to which Data Labels' mapping entries
   are pushed down from directories and which Data Labels' mapping
   entries are pulled.

   For example, assume a data center when hosts in specific Data Labels,
   say VLANs 1 through 100, communicate regularly with external peers,
   the mapping entries for those 100 VLANs should be pushed down to the
   data center gateway routers. For hosts in other Data Labels which
   only communicate with external peers once a day (or once a few days)
   for management interface, the mapping entries for those VLANs should
   be pulled down from directory when the need comes up.

   The mechanisms described above for Push and Pull Directory services
   make it easy to use Push for some Data Labels and Pull for others. In
   fact, different RBridges can even be configured so that some use Push
   Directory services and some use Pull Directory services for the same
   Data Label if both Push and Pull Directory services are available for
   that Data Label. And there can be Data Labels for which directory
   services are not used.



4.1 Strategy Configuration

   Each RBridge that has the ability to use directory assistance has,
   for each Data Label X in which it is might ingress native frames, one
   of four major modes:

      0. No directory use. The RBridge does not subscribe to Push
         Directory data or make Pull Directory requests for Data Label X
         and directory data is not consulted on ingressed frames in Data
         Label X that might have used directory data, including ARP, ND,
         RARP, and unknown MAC destination addresses, are flooded.

      1. Use Push only. The RBridge subscribes to Push Directory data
         for Data Label X.

      2. Use Pull only. When the RBridge ingresses a frame in Data Label
         X that can use Directory information, if it has cached positive


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         information for the address it uses it. If it does not have
         either cached positive or negative information for the address,
         it sends a Pull Directory query.

      3. Use Push and Pull. The RBridge subscribes to Push Directory
         data for Data Label X. When it ingresses a frame in Data Label
         X that can use Directory information,

   The above major Directory use mode is per Data Label. In addition,
   there is a per Data Label per priority minor mode as listed below
   that indicates what should be done if Directory Data is not available
   for the ingressed frame. In all cases, if you are holding Push
   Directory or positive Pull Directory information to handle the frame
   given the major mode, the directory information is simply used and,
   in that instance, the minor modes does not matter.

      A. Flood immediate. Flood the frame immediately (even if you are
         also sending a Pull Directory) request.

      B. Flood. Flood the frame immediately unless you are going to do a
         Pull Directory request, in which case you wait for the response
         or for the request to time out after retries and flood the
         frame if the request times out.

      C. Discard if complete or Flood immediate. If you have complete
         Push Directory information and the address is not in that
         information, discard the frame. Otherwise, the same as A.

      D. Discard if complete or Flood immediate. If you have complete
         Push Directory information and the address is not in that
         information, discard the frame. Otherwise, the same as B.

   In addition, the Pull Directory priority for an Pull Directory
   requests sent can be configured on a per Data Label, per ingressed
   frame priority basis.  The default mappings are as follows:

         Ingress     If Flood    If Flood
         Priority    Immediate   Delayed
         --------    ---------   --------
           7           5           6
           6           5           6
           5           4           5
           4           3           4
           3           2           3
           2           0           2
           0           1           0
           1           1           1

   Priority 7 is normally only used for urgent messages critical to
   network connectivity and so is avoided by default for directory


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   traffic.



















































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5. The Interface Addresses APPsub-TLV

   [[[ This Section 5 is fairly long and complex. Should it be a
   separate document? ]]]

   This section specifies a TRILL APPsub-TLV that enables the convenient
   representation of sets of addresses of different types such that all
   of the addresses in each set designate the same end station interface
   (port). For example, an EUI-48 MAC (Extended Unique Identifier
   48-bit, Media Access Control [RFC5342]) address, IPv4 address, and
   IPv6 address can be reported as all three corresponding to the same
   interface. This APPsub-TLV is used inside the TRILL GENINFO TLV as
   specified in [ESADI] and the value portion is used inside Pull
   Directory responses as specifies in Section 3.

   Although, in some IETF protocols, address field types are represented
   by EtherType [RFC5342] or Hardware Type [RFC5494] only Address Family
   Number is used in this APPsub-TLV.



5.1 Format of the Interface Addresses APPsub-TLV

   The Interface Addresses APPsub-TLV is used to indicate that a set of
   addresses indicate the same end-station interface and to associate
   that interface with the TRILL switch by which the interface is
   reachable. These addresses can be in different address families. For
   example, it can be used to declare that an end-station interface with
   a particular IPv4 address, IPv6 address, and EUI-48 MAC address is
   reachable from a particular TRILL switch.

   The Template field value indicates certain well known sets of
   addresses or gives the number of AFNs following. When AFNs are
   listed, the set of AFNs provides a template for the type and order of
   addresses in each Address Set.

















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      +-+-+-+-+-+-+-+-+
      | Type = TBD    |                  (1 byte)
      +-+-+-+-+-+-+-+-+
      | Length        |                  (1 byte)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Nickname                      |  (2 bytes)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Flags         |                  (1 byte)
      +-+-+-+-+-+-+-+-+
      | Confidence    |                  (1 byte)
      +-+-+-+-+-+-+-+-+
      | Addr Set End  |                  (1 byte)
      +-+-+-+-+-+-+-+-+-+-
      | Template ...                     (variable)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+
      | Address Set 1    (size determined by Template)     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+
      | Address Set 2    (size determined by Template)     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+
      |   ...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+
      | Address Set N    (size determined by Template)     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...-+
      | optional sub-sub-TLVs ...
      +-+-+-+-+-+-+-+-+-+-+-+-...

                 Figure 1. The Interface Addresses APPsub-TLV

   o  Type: Interface Addresses TRILL APPsub-TLV type, set to TBD[#2
      suggested] (IA-SUBTLV).

   o  Length: Variable, minimum 5. If length is 4 or less, the APPsub-
      TLV MUST be ignored.

   o  Nickname: The nickname of the RBridge by which the address sets
      are reachable.

   o  Flags: A byte of flags as follows:

          0 1 2 3 4 5 6 7
         +-+-+-+-+-+-+-+-+
         |D|L|   Resv    |
         +-+-+-+-+-+-+-+-+

         D: If D is one, the APPsub-TLV contains Push Directory
            information.

         L: If L is one, the APPsub-TLV contains information learned
            locally be observing ingressed frames. (Both D and L can one
            in the same APPsub-TLV.)


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         Resv: Additional reserved flag bits that MUST be sent as zero
            and ignored on receipt.

   o  Confidence: This 8-bit quantity indicates the confidence level in
      the addresses being transported [RFC6325].

   o  Addr Set End: The unsigned offset of the byte, within the TLV
      value part, of the last byte of the last Address Set. This will be
      the byte just before the first sub-TLV if any sub-TLVs are
      present. [RFC5305]

   o  Template: The initial byte of this field is the unsigned integer
      K. It K has a value from 1 to 63, it indicates that this initial
      byte is followed by a list of K AFNs (Address Family Numbers) in
      the template specifying the structure and order of each Address
      Set occurring later in the TLV. The minimum valid value is 1. If K
      is 64 to 255, it indicates that the Template for each Address Set
      is a specific well known Template. If the Template includes
      explicit AFNs, they look like the following.

         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         | AFN 1                         |  (2 bytes)
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         | AFN 2                         |  (2 bytes)
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         | ...
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
         | AFN K                         |  (2 bytes)
         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   o  AFN: A two-byte Address Family Number. The number of AFNs present
      is given in first byte of the Template field if that value is less
      than 64. This sequence specifies the structure of the Address Sets
      occurring later in the TLV. For example, if Template Size is 2 and
      the two AFNs present are the AFNs for IPv4 and EUI-48, in that
      order, then each Address set present will consist of a 4-byte IPv4
      address followed by a 6-byte MAC address. If any AFNs are present
      that are unknown to the receiving IS and the length of the
      corresponding address is not provided by a sub-TLV as specified
      below, the receiving IS will be unable to parse the Address Sets
      and MUST ignore the enclosing TLV.

   o  Address Set: Each address set consists of a sequence of addresses
      of the types given by the Template earlier in the TLV. No
      alignment, other than to a byte boundary, is guaranteed. The
      addresses in each Address Set are contiguous with no unused bytes
      between them and the Address Sets are contiguous with no unused
      bytes between Address Sets. The Address Sets must fit within the
      TLV. If the product of the size of an Address Set and the number
      of Address Sets is so large that this is not true, the APPsub-TLV


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      is ignored.

   o sub-sub-TLVs: If the Address Sets indicated by Addr Sets End do not
      completely fill the Length of the TLV, the remaining bytes are
      parsed as sub-sub-TLVs [RFC5305]. Any such sub-sub-TLVs that are
      not known to the receiving RBridge are ignored. Should this not be
      possible, for example there is only one remaining byte or an
      apparent sub-sub-TLV extends beyond the end of the TLV, the
      containing IA-APPsub-TLV is considered corrupt and is ignored.
      Several sub-sub-TLV types are specified in Section 5.2.

   Different IA-APPsub-TLVs within the same or different EADI-LSPs or
   Pull Directory response from the same RBridge may have different
   Templates. The same AFN may occur more than once in a Template and
   the same address may occur in more than one address set. For example,
   an EUI-48 MAC address interface might have three IPv6 addresses. This
   could be represented by an IA-APPsub-TLV whose Template specifically
   provided for one EUI-48 address and three IPv6 addresses, which might
   be an efficient format if there were multiple interfaces with that
   pattern. Alternatively, a Template with one EUI-48 and one IPv6
   address could be used in an IA-APPsub-TLV with three address sets
   each having the same EUI-48 address but different IPv6 addresses,
   which might be the most efficient format if only one interface had
   multiple IPv6 addresses and other interfaces had only one IPv6
   address.

   In order to be able to parse the Address Sets, a receiving RBridge
   must know at least the size of the address each AFN in the Template
   specifies; however, the presence of the Addr Set End field means that
   the sub-TLVs, if any, can always be located by a receiving IS.  An
   RBridge can be assumed to know the size of IPv4 and IPv6 addresses
   (AFNs 1 and 2) and the size of the additional AFNs allocated by the
   IANA Considerations below. Should an RBridge wish to include an AFN
   that some receiving RBridge in the campus may not know, it SHOULD
   include an AFN-Size sub-sub-TLV as described below. If an IA-APPsub-
   TLV is received with one or more AFNs in its template for which the
   receiving RBridge does not know the length and for which an AFN-Size
   sub-sub-TLV is not present, that IA-APPsub-TLV will be ignored.



5.2 IA-APPsub-TLV sub-sub-TLVs

   IA-APPsub-TLVs may have trailing sub-sub-TLVs [RFC5305] as specified
   below.  These sub-sub-TLVs occur after the Address Sets and the
   amount of space available for sub-sub-TLVs is determined from the
   overall IA-APPsub-TLV length and the value of the Addr Set End byte.

   There is no ordering restriction on sub-sub-TLVs. Unless otherwise
   specified each sub-sub-TLV type can occur zero, one, or many times in


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   an IA-APPsub-TLV.



5.2.1 AFN Size sub-sub-TLV

   Using this sub-TLV, the originating RBridge can specify the size of
   an address type. This is useful under two circumstances:

   1. One or more AFNs that are unknown to the receiving RBridge appears
      in the template. If an AFN Size sub-sub-TLV is present for each
      such AFN, the at least the IA-APPsub-TLV can be parses the Address
      Sets and make use of any address types present that it does
      understand.

   2. If an AFN occurs in the Template that represents a variable length
      address, this sub-sub-TLV gives its size for all occurrences in
      that IA-APPsubTLV.

      +-+-+-+-+-+-+-+-+
      | Type = AFNsz  |                  (1 byte)
      +-+-+-+-+-+-+-+-+
      | Length        |                  (1 byte)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | AFN Size Record(s)                            |  (3 bytes)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Where each AFN Size Record is structured as follows:

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  AFN                          |  (2 bytes)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  AdrSize      |                  (1 byte)
      +-+-+-+-+-+-+-+-+

   o  Type: AFN-Size sub-sub-TLV type, set to 1 (AFNsz).

   o  Length: 3*n where n is the number of AFN Size Records present. If
      n is not a multiple of 3, the sub-sub-TLV MUST be ignored.

   o  AFN Size Record(s): Zero or more 3-byte records, each giving the
      size of an address type identified by an AFN,

   o  AFN: The AFN whose length is being specified by the AFN Size
      Record.

   o  AdrSize: The length of the address specified by the AFN field.

   This sub-sub-TLV may occur multiple times in an enclosing IA-APPsub-
   TLV.


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   An AFN Size sub-sub-TLV for any AFN known to the receiving RBridge
   (which always includes AFN 1 and 2 and the AFNs specified in xxx) is
   compared with the size known to the RBridge and if they differ, the
   IA-APPsub-TLV is ignored.



5.2.2 Fixed Address sub-sub-TLV

   There may be cases where, in an Interface Addresses TLV, the same
   address would appear across every address set in the TLV. To avoid
   having a larger template and wasted space in all Address Sets, this
   sub-sub-TLV can be used to indicate such a fixed address

      +-+-+-+-+-+-+-+-+
      |Type=FIXEDADR  |                 (1 byte)
      +-+-+-+-+-+-+-+-+
      | Length        |                 (1 byte)
      +-+-+-+-+-+-+-+-+
      | AFN           |                 (2 bytes)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      | Fixed Address                   (variable)
      +-+-+-+-+-+-+-+-+-+-+-+-+-...

   o  Type: Data Label sub-sub-TLV type, set to 2 (FIXEDADR).

   o  Length: variable, minimum 3. If Length is 2 or less, the sub-sub-
      TLV MUST be ignored.

   o  AFN: Address Family Number of the Fixed Address.

   o  Fixed Address: The address of the type indicated by the preceding
      AFN field that is considered to be part of every Address Set in
      the IA-APPsub-TLV.



5.2.3 Data Label sub-sub-TLV

   When used with Push or Pull Directories, the Data Label is indicated
   by the Data Label of the ESADI instance (Push) or RBridge Channel
   message (Pull) in which the IA APPsub-TLV appears and any occurrence
   of this sub-sub-TLV is ignored. However, the IA APPsub-TLV might be
   used in other contexts where this sub-sub-TLV indicates the Data
   Label of the Address Sets and multiple occurrences of this sub-sub-
   TLV indicate that the Address Sets exist in all of the Data Labels.






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      +-+-+-+-+-+-+-+-+
      |Type=DATALEN   |                 (1 byte)
      +-+-+-+-+-+-+-+-+
      | Length        |                 (1 byte)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      | Data Label                      (variable)
      +-+-+-+-+-+-+-+-+-+-+-+-+-...

      o  Type: Data Label sub-TLV type, set to 3 (DATALEN).

      o  Length: 2 or 3

      o  Data Label: If length is 2, the bottom 12 bits of the Data
         Label are a VLAN ID and the top 4 bits are reserved (MUST be
         sent as zero and ignored on receipt). If the length is 3, the
         three Data Label bytes contain an FGL [RFCfgl].



5.2.4 Topology sub-sub-TLV

   The presence of this sub-sub-TLV indicates that the Address Sets are
   in the topology give. If it occurs multiple times, then the Address
   Sets are in all of the topologies listed.

      +-+-+-+-+-+-+-+-+
      |Type=DATALEN   |                  (1 byte)
      +-+-+-+-+-+-+-+-+
      | Length        |                  (1 byte)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | RESV  |        Topology       |  (2 bytes)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      o  Type: Data Label sub-TLV type, set to 3 (DATALEN).

      o  Length: 2.

      RESV: Four reserved bits. MUST be sent as zero and ignored on
         receipt.

      o  Topology: The 12-bit topology number.











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6. Security Considerations

   Push Directory data is distributed through ESADI-LSPs [ESADI] which
   can be authenticated with the same mechanisms as IS-IS LSPs. See
   [RFC5304] and [RFC5310].

   Pull Directory queries and responses are transmitted as RBridge-to-
   RBridge or native RBridge Channel messages. Such messages can be
   secured by TBD

   For general TRILL security considerations, see [RFC6325].









































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7. IANA Considerations

   This section give IANA allocation and registry considerations.



7.1 ESADI-Parameter Bits

   IANA is request to allocate two ESADI-Parameter TRILL APPsub-TLV flag
   bits for "Push Directory" and "Complete Push" and to create a sub-
   registry in the TRILL Parameters Registry as follows:

      Sub-Registry: ESADI-Parameter APPsub-TLV Bits

      Registration Procedures: IETF Review

      References: [ESADI], This document

         Bit  Mnemonic  Description                      Reference
         ---  --------  -----------                      ---------
          0      UN     Supports Unicast ESADI           [ESADI]
          1      PD     Push Directory Server            This document
          2      CP     Complete Push                    This document
         3-7     -      available for allocation



7.2 RBridge Channel Protocol Number

   IANA is requested to allocate a new RBridge Channel protocol number
   for "Pull Directory Services" from the range allocable by Standards
   Action and update the table of such protocol number in the TRILL
   Parameters Registry referencing this document.



7.3 Pull Directory and No Data Bits

   IANA is requested to allocate two currently reserved bits in the
   Interested VLANs field of the Interested VLANs sub-TLV (suggested
   bits 3 and 4) and the Interested Labels field of the Interested
   Labels sub-TLV (suggested bits 5 and 6) [rfc6326bis] to indicate Pull
   Directory server (PD) and No Data (ND) respectively. These bits are
   to be added to the subregistry set up in [ESADI].

   In the TRILL base protocol [RFC6325] as extended for FGL [rfcFGL],
   the mere presence of an Interested VLANs or Interested Labels sub-
   TLVs in the LSP of an RBridge indicates connection to end stations in
   the VLANs or FGLs listed and thus a desire to receive multi-
   destination traffic in those Data Labels although multicast traffic


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   might be pruned. But, with Push and Pull Directories, advertising
   that you are a directory server requires using these sub-TLVs as part
   of advertising that you are a directory server. If such a directory
   server does not wish to received multi-destination user data for the
   Data Labels it lists in one of these sub-TLVs, it sets the "No Data"
   (ND) bit to one. This means that data on a distribution tree may be
   pruned so as not to reach the "No Data" RBridge as long as there are
   no RBridges interested in the Data who are beyond the "No Data"
   RBridge.  This bit is backwards compatible as RBridges ignorant of it
   will simply no prune when it could, which is safe but may cause
   increased link utilization.



7.4 Additional AFN Number Allocation

   IANA is requested to allocate four new AFN numbers as follows:

      Number   Description   References ------   -----------
      ----------

      TBD(26)  EUI-48        RFC 5342, this document
      TBD(27)  OUI           RFC 5342, this document
      TBD(28)  MAC/24        This document.
      TBD(29)  IPv6/64       This document.

   The OUI AFN is provided so that MAC addresses can be abbreviated if
   they have the same upper 24 bits. In particular, if there is an OUI
   provided as a Fixed Address sub-sub-TLV (see Section 5.2.2) then,
   whenever a MAC/24 address appears within an Address Set (as indicated
   by the Template), the OUI is used as the first 24 bits of the actual
   MAC address for the Address Set.

   MAC/24 is a 24-bit suffixes intended to be pre-fixed by an OUI as in
   the previous paragraph. In absence of an OUI specified as a Fixed
   Address in the same APPsub-TLV, the Address Set cannot be used.

   IPv6/64 is an 8-byte quantity that is the first 64 bits of an IPv6
   address. If present, there will normally be an EUI-64 address in the
   address set to provide the lower 64 bits of the IPv6 address. For
   this purpose, an EUI-48 is expanded to 64 bits as described in
   [RFC5342].



7.5 IA APPsub-TLV Sub-Sub-TLVs SubRegistry

   IANA is requested to establish a new subregistry for sub-sub-TLVs of
   the Interface Addresses APPsub-TLV with initial contents as shown
   below.


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      Name:       Interface Addresses APPsub-TLV Sub-Sub-TLVs

      Procedure:  IETF Review

      Reference:  This document

         Type   Description       Reference
         ----   -----------       ---------
           0    Reserved
           1    AFN Size          This document
           2    Fixed Address     This document
           3    Data Label        This document
           4    Topology          This document
         5-254  Available         This document
          255   Reserved





































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8. Acknowledgments

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
















































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9. References

   Normative and Informational References are given below.



9.1 Normative References

   [RFC826] - Plummer, D., "An Ethernet Address Resolution Protocol",
         RFC 826, November 1982.

   [RFC903] - Finlayson, R., Mann, T., Mogul, J., and M. Theimer, "A
         Reverse Address Resolution Protocol", STD 38, RFC 903, June
         1984

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

   [RFC4861] - Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
         "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
         September

   [RFC5304] Li, T. and R. Atkinson, "IS-IS Cryptographic
         Authentication", RFC 5304, October 2008.

   [RFC5310] - Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
         and M. Fanto, "IS-IS Generic Cryptographic Authentication", RFC
         5310, February 2009.

   [RFC5305] - Li, T. and H. Smit, "IS-IS Extensions for Traffic
         Engineering", RFC 5305, October 2008.

   [RFC5342] - Eastlake 3rd, D., "IANA Considerations and IETF Protocol
         Usage for IEEE 802 Parameters", BCP 141, RFC 5342, September
         2008.

   [RFC5494] - Arkko, J. and C. Pignataro, "IANA Allocation Guidelines
         for the Address Resolution Protocol (ARP)", RFC 5494, April
         2009.

   [RFC6165] - Banerjee, A. and D. Ward, "Extensions to IS-IS for
         Layer-2 Systems", RFC 6165, April 2011

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

   [rfc6326bis] - Eastlake, D., Banerjee, A., Dutt, D., Perlman, R., and
         A. Ghanwani, "TRILL Use of IS-IS", draft-ietf-isis-
         rfc6326bis-00.txt, work in progress.


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   [RFCclear] - Eastlake, D., M. Zhang, A. Ghanwani, V. Manral, A.
         Banerjee, draft-ietf-trill-clear-correct-06.txt, in RFC
         Editor's queue.

   [Channel] - D. Eastlake, V. Manral, Y. Li, S. Aldrin, D. Ward,
         "TRILL: RBridge Channel Support", draft-ietf-trill-rbridge-
         channel-08.txt, in RFC Editor's queue.

   [RFCfgl] - D. Eastlake, M. Zhang, P. Agarwal, R. Perlman, D. Dutt,
         "TRILL: Fine-Grained Labeling", draft-ietf-trill-fine-
         labeling-05.txt, work in progress.

   [ESADI] - Zhai, H., F. Hu, R. Perlman, D. Eastlake, J. Hudson, "TRILL
         (Transparent Interconnection of Lots of Links): The ESADI (End
         Station Address Distribution Information) Protocol", draft-
         ietf-trill-esadi-02.txt, work in progress.



9.2 Informational References

   [RFC5342] - Eastlake 3rd, D., "IANA Considerations and IETF Protocol
         Usage for IEEE 802 Parameters", BCP 141, RFC 5342, September
         2008

   [DirectoryFramework] - Dunbar, L., D. Eastlkae, R. Perlman, I.
         Gashinsky, "TRILL Edge Directory Assistance Framework", draft-
         ietf-trill-directory-framework-03.txt, work in progress.

   [ARP reduction] - Shah, et. al., "ARP Broadcast Reduction for Large
         Data Centers", Oct 2010.





















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Authors' Addresses

   Linda Dunbar
   Huawei Technologies
   5430 Legacy Drive, Suite #175
   Plano, TX 75024, USA

   Phone: (469) 277 5840
   Email: ldunbar@huawei.com


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

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


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

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


   Igor Gashinsky
   Yahoo
   45 West 18th Street 6th floor
   New York, NY 10011

   Email: igor@yahoo-inc.com


   Yizhou Li
   Huawei Technologies
   101 Software Avenue,
   Nanjing 210012 China

   Phone: +86-25-56622310
   Email: liyizhou@huawei.com








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Copyright, Disclaimer, and Additional IPR Provisions

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   be considered to be definitive versions of IETF Documents. The
   definitive version of these Legal Provisions is that published by, or
   under the auspices of, the IETF. Versions of these Legal Provisions
   that are published by third parties, including those that are
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   doubt, each Contributor to the IETF Standards Process licenses each
   Contribution that he or she makes as part of the IETF Standards
   Process to the IETF Trust pursuant to the provisions of RFC 5378. No
   language to the contrary, or terms, conditions or rights that differ
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   published or posted by such Contributor, or included with or in such
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L. Dunbar, et al                                               [Page 36]


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