INTERNET-DRAFT                                           Donald Eastlake
Intended status: Proposed Standard                             Yizhou Li
                                                           Radia Perlman
Expires: January 14, 2014                                  July 15, 2013

                 TRILL: Interface Addresses APPsub-TLV

   This document specifies a TRILL (Transparent Interconnection of Lots
   of Links) IS-IS application sub-TLV that enables the reporting by a
   TRILL switch sets of addresses such that all of the addresses in each
   set designate the same interface (port). For example, an EUI-48 MAC
   (Extended Unique Identifier 48-bit, Media Access Control) address,
   IPv4 address, and IPv6 address can be reported as all corresponding
   to the same interface. Such information could be used, for example,
   to synthesize responses to or by-pass the need for the Address
   Resolution Protocol (ARP), the IPv6 Neighbor Discovery (ND) protocol,
   of the flooding of unknown MAC addresses, in some cases.

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
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   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
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   The list of current Internet-Drafts can be accessed at The list of Internet-Draft
   Shadow Directories can be accessed at

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Table of Contents

      1. Introduction............................................3
      1.1 Conventions Used in This Document......................3

      2. Format of the Interface Addresses APPsub-TLV............4

      3. IA-APPsub-TLV sub-sub-TLVs..............................8
      3.1 AFN Size sub-sub-TLV...................................8
      3.2 Fixed Address sub-sub-TLV..............................9
      3.3 Data Label sub-sub-TLV.................................9
      3.4 Topology sub-sub-TLV..................................10

      4. Security Considerations................................11

      5. IANA Considerations....................................11
      5.1 Additional AFN Number Allocation......................11
      5.2 IA APPsub-TLV Sub-Sub-TLVs SubRegistry................11

      Normative References......................................13
      Informational References..................................14
      Authors' Addresses........................................15

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1. Introduction

   This document specifies a TRILL (Transparent Interconnection of Lots
   of Links) [RFC6325] IS-IS application sub-TLV (APPsub-TLV [RFC6823])
   that enables the convenient representation of sets of addresses 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 [RFC5342bis]) 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]. It is expected to be used in Directory Assisted TRILL Edge
   services [DirectoryFramework].

   Although, in some IETF protocols, address field types are represented
   by EtherType [RFC5342bis] or Hardware Type [RFC5494] only Address
   Family Number is used in this APPsub-TLV.

1.1 Conventions Used in This Document

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

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2. 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 indicates certain well known sets of addresses or
   gives a number of AFNs. When AFNs are listed, the set of AFNs
   provides an explicit template for the type and order of addresses in
   each Address Set.

      | 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

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      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

         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.)

         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)

      For K in the 64 to 255 range, some values indicate combinations of
      a specific number of 48-bit MAC addresses, IPv4 addresses, and
      IPv6 addresses in that order. If M is the number of MAC addresses
      (limited to 1 or 2), v4 is the number of IPv4 addresses (limited

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      to 0, 1, or 2) and v6 is the number of IPv6 addresses (limited to
      0 through 4 inclusive), the value of K is

         K = 63 + M + 2*v4 + 6*v6

      That equation specifies values of K from 64 through 93. Values
      from 94 through 255 are available for assignment by IETF Review.

   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 EUI-48 and IPv4, in that
      order, then each Address set present will consist of a 6-byte MAC
      address followed by a 4-byte IPv4 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
      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 3.

   Different IA-APPsub-TLVs within the same or different ESADI-LSPs or
   Pull Directory responses 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,

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   which might be the most efficient format if only one interface had
   multiple IPv6 addresses and other interfaces had only one IPv6

   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 EUI-48, IPv4, and IPv6
   addresses (AFNs 16389, 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.

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3. 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
   an IA-APPsub-TLV.

3.1 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, then at least the IA-APPsub-TLV can be parsed.

   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,

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

   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-

   An AFN Size sub-sub-TLV for any AFN known to the receiving RBridge
   (which always includes AFN 1, 2, and 16389 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.

3.2 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.

3.3 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

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   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.

      |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].

3.4 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

      o  Topology: The 12-bit topology number [RFC5120].

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4. Security Considerations


5. IANA Considerations

5.1 Additional AFN Number Allocation

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

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

      TBD(29)  OUI           [RFC5342bis], this document
      TBD(30)  MAC/24        This document.
      TBD(31)  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 suffix 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, an Address Set containing an MAC/24
   address 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-48 or 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 [RFC5342bis].

5.2 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

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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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   The authors gratefully acknowledge the contributions and review by
   the following:

         Linda Dunbar

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

Normative References

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

   [RFC5120] - Przygienda, T., Shen, N., and N. Sheth, "M-ISIS: Multi
         Topology (MT) Routing in Intermediate System to Intermediate
         Systems (IS-ISs)", RFC 5120, February 2008.

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

   [RFC5342bis] - 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

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

   [RFC6823] - Ginsberg, L., Previdi, S., and M. Shand, "Advertising
         Generic Information in IS-IS", RFC 6823, December 2012.

   [RFCfgl] - D. Eastlake, M. Zhang, P. Agarwal, R. Perlman, D. Dutt,
         "TRILL: Fine-Grained Labeling", draft-ietf-trill-fine-
         labeling-07.txt, in RFC Editor's queue.

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

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Informational References

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

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

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Authors' Addresses

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

   Phone: 1-508-333-2270

   Yizhou Li
   Huawei Technologies
   101 Software Avenue,
   Nanjing 210012 China

   Phone: +86-25-56622310

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

   Phone: +1-408-765-8080

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Copyright, Disclaimer, and Additional IPR Provisions

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