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Transparent Interconnection of Lots of Links (TRILL): RBridge Channel Header Extension
draft-ietf-trill-channel-tunnel-11

The information below is for an old version of the document that is already published as an RFC.
Document Type
This is an older version of an Internet-Draft that was ultimately published as RFC 7978.
Authors Donald E. Eastlake 3rd , Mohammed Umair , Yizhou Li
Last updated 2016-09-30 (Latest revision 2016-08-05)
Replaces draft-eastlake-trill-channel-tunnel
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draft-ietf-trill-channel-tunnel-11
INTERNET-DRAFT                                           Donald Eastlake
Updates: 7178                                                     Huawei
Intended status: Proposed Standard                        Mohammed Umair
                                                              IPinfusion
                                                               Yizhou Li
                                                                  Huawei
Expires: February 4, 2017                                 August 5, 2016

                TRILL: RBridge Channel Header Extension
                <draft-ietf-trill-channel-tunnel-11.txt>

Abstract

   The IETF TRILL (Transparent Interconnection of Lots of Links)
   protocol includes an optional mechanism (specified in RFC 7178)
   called RBridge Channel for the transmission of typed messages between
   TRILL switches in the same campus and the transmission of such
   messages between TRILL switches and end stations on the same link.
   This document specifies extensions to the RBridge Channel protocol
   header to support two features as follows: (1) a standard method to
   tunnel payloads whose type can be indicated by Ethertype through
   encapsulation in RBridge Channel messages; and (2) a method to
   support security facilities for RBridge Channel messages. This
   document updates RFC 7178.

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 authors or the TRILL working group mailing list:
   trill@ietf.org

   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.

D. Eastlake, M. Umair, & Y. Li                                  [Page 1]
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Table of Contents

      1. Introduction............................................3
      1.1  Terminology and Acronyms..............................3

      2. RBridge Channel Header Extension Format.................5

      3. Extended RBridge Channel Payload Types..................8
      3.1 Null Payload...........................................8
      3.2 Ethertyped Payload.....................................8
      3.2.1 RBridge Channel Message as the Payload...............9
      3.2.2 TRILL Data Packet as the Payload.....................9
      3.2.3 TRILL IS-IS Packet as the Payload...................10
      3.3 Ethernet Frame........................................11

      4. Extended RBridge Channel Security......................14
      4.1 Derived Keying Material...............................14
      4.2 SType None............................................15
      4.3 [RFC5310]-Based Authentication........................15
      4.4 DTLS Pairwise Security................................17
      4.5 Composite Security....................................18

      5. Extended RBridge Channel Errors........................19
      5.1 SubERRs...............................................19
      5.2 Secure Nested RBridge Channel Errors..................19

      6. IANA Considerations....................................21
      6.1 Extended RBridge Channel Protocol Number..............21
      6.2 RBridge Channel Protocol Subregistries................21
      6.2.1 RBridge Channel Error Codes.........................21
      6.2.2 RBridge Channel SubError Codes......................21
      6.2.3 Extended RBridge Channel Payload Types Subregistry..22
      6.2.4 Extended RBridge Channel Security Types Subregistry.22

      7. Security Considerations................................23

      Normative References......................................24
      Informative References....................................25

      Appendix Z: Change History................................27
      Acknowledgements..........................................29
      Authors' Addresses........................................30

D. Eastlake, M. Umair, & Y. Li                                  [Page 2]
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1. Introduction

   The IETF TRILL base protocol [RFC6325] [RFC7780] has been extended
   with the RBridge Channel [RFC7178] facility to support transmission
   of typed messages (for example BFD (Bidirectional Forwarding
   Detection) [RFC7175]) between two TRILL switches (RBridges) in the
   same campus and the transmission of such messages between RBridges
   and end stations on the same link. When sent between RBridges in the
   same campus, a TRILL Data packet with a TRILL Header is used and the
   destination RBridge is indicated by nickname. When sent between a
   RBridge and an end station on the same link in either direction, a
   native RBridge Channel message [RFC7178] is used with no TRILL Header
   and the destination port or ports are indicated by a MAC address.
   (There is no mechanism to stop end stations on the same link from
   sending native RBridge Channel messages to each other; however, such
   use is outside the scope of this document.)

   This document updates [RFC7178] and specifies extensions to the
   RBridge Channel header that provide two additional facilities as
   follows:

      (1) A standard method to tunnel payloads whose type may be
          indicated by Ethertype through encapsulation in RBridge
          Channel messages.

      (2) A method to provide security facilities for RBridge Channel
          messages. Example uses requiring such facilities are the
          security of Pull Directory messages [RFC7067], address flush
          messages [AddrFlush], and port shutdown messages [rfc6439bis].

   Use of each of these facilities is optional, except that, as
   specified below, if this header extension is implemented there are
   two payload types that MUST be implemented. Both of the above
   facilities can be used in the same packet. In case of conflict
   between this document and [RFC7178], this document takes precedence.

1.1  Terminology and Acronyms

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

   This document uses terminology and acronyms defined in [RFC6325] and
   [RFC7178].  Some of these are repeated below for convenience along
   with additional new terms and acronyms.

      application_data - A DTLS [RFC6347] message type.

D. Eastlake, M. Umair, & Y. Li                                  [Page 3]
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      Data Label - VLAN or FGL.

      DTLS - Datagram Transport Level Security [RFC6347].

      FCS - Frame Check Sequence.

      FGL - Fine Grained Label [RFC7172].

      HKDF - HMAC-based Key Derivation Function [RFC5869].

      IS-IS - Intermediate System to Intermediate Systems [IS-IS].

      PDU - Protocol Data Unit.

      MTU - Maximum Transmission Unit.

      RBridge - An alternative term for a TRILL switch.

      SHA - Secure Hash Algorithm [RFC6234].

      Sz - Campus-wide minimum link MTU [RFC6325] [RFC7780].

      TRILL - Transparent Interconnection of Lots of Links or Tunneled
         Routing in the Link Layer.

      TRILL switch - A device that implements the TRILL protocol
         [RFC6325] [RFC7780], sometimes referred to as an RBridge.

D. Eastlake, M. Umair, & Y. Li                                  [Page 4]
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2. RBridge Channel Header Extension Format

   The general structure of an RBridge Channel message between two TRILL
   switches (RBridges) in the same campus is shown in Figure 2.1 below.
   The structure of a native RBridge Channel message sent between an
   RBridge and an end station on the same link, in either direction, is
   shown in Figure 2.2 and, compared with the first case, omits the
   TRILL Header, inner Ethernet addresses, and Data Label. A Protocol
   field in the RBridge Channel Header gives the type of RBridge Channel
   message and indicates how to interpret the Channel Protocol Specific
   Payload [RFC7178].

                      +-----------------------------------+
                      |           Link Header             |
                      +-----------------------------------+
                      |           TRILL Header            |
                      +-----------------------------------+
                      |      Inner Ethernet Addresses     |
                      +-----------------------------------+
                      |      Data Label (VLAN or FGL)     |
                      +-----------------------------------+
                      |      RBridge Channel Header       |
                      +-----------------------------------+
                      | Channel Protocol Specific Payload |
                      +-----------------------------------+
                      |   Link Trailer (FCS if Ethernet)  |
                      +-----------------------------------+

                   Figure 2.1 RBridge Channel Packet Structure

                      +-----------------------------------+
                      |       Ethernet Link Header        |
                      +-----------------------------------+
                      |      RBridge Channel Header       |
                      +-----------------------------------+
                      | Channel Protocol Specific Payload |
                      +-----------------------------------+
                      |                FCS                |
                      +-----------------------------------+

                     Figure 2.2 Native RBridge Channel Frame

   The RBridge Channel Header looks like this:

D. Eastlake, M. Umair, & Y. Li                                  [Page 5]
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                           1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         0x8946                | CHV=0 |   Channel Protocol    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Flags         |  ERR  |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               /
      /                             Channel Protocol Specific Data    /
      /-+-+-+-+-+-                                                    /

                      Figure 2.3 RBridge Channel Header

   where 0x8946 is the RBridge Channel Ethertype and CHV is the Channel
   Header Version. This document is based on RBridge Channel version
   zero.

   The header extensions specified herein are in the form of an RBridge
   Channel protocol, the Extended RBridge Channel Protocol.  Figure 2.4
   below expands the RBridge Channel Header and Protocol Specific
   Payload above for the case where the header extension is present.

                           1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 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
    RBridge Channel Header:
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         0x8946                | CHV=0 | Channel Protocol=[TBD]|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         Flags         |  ERR  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    Header Extension Specific:        | SubERR| RESV4 | SType | PType |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      | Security Information, variable length (0 length if SType = 0) /
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      |      Tunneled Data, variable length
      |  ...

           Figure 2.4 RBridge Channel Header Extension Structure

   The RBridge Channel Header Protocol field is used to indicate that
   the header extension is present. Its contents MUST be the value
   allocated for this purpose (see Section 6). The use of an RBridge
   Channel protocol to indicate extension makes it easy to determine if
   a remote RBridge in the campus supports extension since RBridges
   advertise in their LSP which such protocols they support.

   The Extended RBridge Channel Protocol Specific Data fields are as
   follows:

D. Eastlake, M. Umair, & Y. Li                                  [Page 6]
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      SubERR: This field provides further details when an error is
         indicated in the RBridge Channel ERR field. If ERR is zero,
         then SubERR MUST be sent as zero and ignored on receipt. See
         Section 5.

      RESV4: This field MUST be sent as zero. If non-zero when received,
         this is an error condition (see Section 5).

      SType: This field describes the type of security information and
         features, including keying material, being used or provided by
         the extended RBridge Channel message. See Section 4.

      PType: Payload type. This describes the tunneled data. See Section
         3 below.

      Security Information: Variable length information. Length is zero
         if SType is zero. See Section 4.

   The RBridge Channel Header Extension is integrated with the RBridge
   Channel facility.  Extension errors are reported as if they were
   RBridge Channel errors, using newly allocated code points in the ERR
   field of the RBridge Channel Header supplemented by the SubERR field.

D. Eastlake, M. Umair, & Y. Li                                  [Page 7]
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3. Extended RBridge Channel Payload Types

   The Extended RBridge Channel Protocol can carry a variety of payloads
   as indicated by the PType (Payload Type) field. Values are shown in
   the table below with further explanation after the table (see also
   Section 6.2.2).

         PType  Description         Reference
         -----  -----------         ---------
            0   Reserved
            1   Null                Section 3.1 of [this doc]
            2   Ethertyped Payload  Section 3.2 of [this doc]
            3   Ethernet Frame      Section 3.3 of [this doc]
         4-14   Unassigned
           15   Reserved

                       Table 3.1 Payload Type Values

   While implementation of the RBridge Channel Header Extension is
   optional, if it is implemented PType 1 (Null) MUST be implemented and
   PType 2 (Ethertyped Payload) with the RBridge Channel Ethertype MUST
   be implemented.  PType 2 for any Ethertypes other than the RBridge
   Channel Ethertype MAY be implemented. PType 3 MAY be implemented.

   The processing of any particular extended header RBridge Channel
   message and its payload depends on meeting local security and other
   policy at the destination TRILL switch or end station.

3.1 Null Payload

   The Null payload type (PType = 1) is intended to be used for testing
   or for messages such as key negotiation or the like where only
   security information is present. It indicates that there is no user
   data payload. Any tunneled user data after the Security Information
   field is ignored. If the RBridge Channel Header Extension is
   implemented, the Null Payload MUST be supported in the sense that an
   "Unsupported PType" error is not returned (see Section 5).  Any
   particular use of the Null Payload should specify what VLAN or FGL
   and what priority should be used in the inner Data Label of the
   RBridge Channel message (or in an outer VLAN tag for the native
   RBridge Channel message case) when those values are relevant.

3.2 Ethertyped Payload

   A PType of 2 indicates that the payload (tunneled data) of the
   extended RBridge Channel message begins with an Ethertype. A TRILL

D. Eastlake, M. Umair, & Y. Li                                  [Page 8]
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   switch supporting the RBridge Channel Header Extension MUST support a
   PType of 2 with a payload beginning with the RBridge Channel
   Ethertype as described in Section 3.2.1. Other Ethertypes, including
   the TRILL and L2-IS-IS Ethertypes as described in Section 3.2.2 and
   3.2.3, MAY be supported.

3.2.1 RBridge Channel Message as the Payload

   A PType of 2 whose payload has an initial RBridge Channel Ethertype
   indicates an encapsulated RBridge Channel message. A typical reason
   for sending an RBridge Channel message inside an extended RBridge
   Channel message is to provide security services, such as
   authentication or encryption, for the encapsulated message.

   This RBridge Channel message type looks like the following:

                           1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    RBridge-Channel (0x8946)   | CHV=0 | Channel Protocol=[TBD]|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |          Flags        |  ERR  | SubERR| RESV4 | SType |  0x2  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      / Security Information, variable length (0 length if SType = 0) /
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    RBridge-Channel (0x8946)   | CHV=0 |Nested Channel Protocol|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |          Flags        |  ERR  |                               |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
      |         Nested Channel Protocol Specific Data ...             /
      /                                                               /

         Figure 3.1 Message Structure with RBridge Channel Payload

3.2.2 TRILL Data Packet as the Payload

   A PType of 2 whose payload has an initial TRILL Ethertype indicates
   an encapsulated TRILL Data packet as shown in the figure below.  If
   this Ethertype is supported for PType = 2 and the message meets local
   policy for acceptance, the TRILL Data packet is handled as if it had
   been received by the destination TRILL switch on the port where the
   Extended RBridge Channel message was received.

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                           1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    RBridge-Channel (0x8946)   | CHV=0 | Channel Protocol=[TBD]|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |          Flags        |  ERR  | SubERR| RESV4 | SType |  0x2  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      / Security Information, variable length (0 length if SType = 0) /
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |        TRILL (0x22F3)         | V |A|C|M| RESV  |F| Hop Count |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |       Egress Nickname         |      Ingress Nickname         |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      /                       Optional Flags Word                     /
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          Inner.MacDA                          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    Inner.MacDA continued      |          Inner.MacSA          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                       Inner.MacSA (cont.)                     |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                 Inner Data Label (2 or 4 bytes)
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      |  TRILL Data Packet payload
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...

        Figure 3.2 Message Structure with TRILL Data Packet Payload

   The optional flags word is only present if the F bit in the TRILL
   Header is one [RFC7780].

3.2.3 TRILL IS-IS Packet as the Payload

   A PType of 2 and an initial L2-IS-IS Ethertype indicates that the
   payload of the Extended RBridge Channel protocol message is an
   encapsulated TRILL IS-IS PDU as shown in Figure 3.3. If this
   Ethertype is supported for PType = 2, the tunneled TRILL IS-IS packet
   is processed by the destination RBridge if it meets local policy. One
   possible use is to expedite the receipt of a link state PDU (LSP) by
   some TRILL switch or switches with an immediate requirement for the
   link state information.  A link local IS-IS PDU (Hello, CSNP, or PSNP
   [IS-IS]; MTU-probe or MTU-ack [RFC7176]; or circuit scoped FS-LSP,
   FS-CSNP or FS-PSNP [RFC7356]) would not normally be sent via this
   Extended RBridge Channel method except possibly to encrypt it since
   such PDUs can just be transmitted on the link and do not normally
   need RBridge Channel handling.

D. Eastlake, M. Umair, & Y. Li                                 [Page 10]
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                           1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    RBridge-Channel (0x8946)   | CHV=0 | Channel Protocol=[TBD]|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |          Flags        |  ERR  | SubERR| RESV4 | SType |  0x2  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      / Security Information, variable length (0 length if SType = 0) /
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      |  L2-IS-IS (0x22F4)            |     0x83      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         rest of IS-IS PDU
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-...

       Figure 3.3 Message Structure with TRILL IS-IS Packet Payload

3.3 Ethernet Frame

   If PType is 3, the extended RBridge Channel payload is an Ethernet
   frame as might be received from or sent to an end station except that
   the encapsulated Ethernet frame's FCS is omitted, as shown in Figure
   3.4. (There is still an overall final FCS if the RBridge Channel
   message is being sent on an Ethernet link.) If this PType is
   implemented and the message meets local policy, the encapsulated
   frame is handled as if it had been received on the port on which the
   Extended RBridge Channel message was received.

   The priority of the RBridge Channel message can be copied from the
   Ethernet frame VLAN tag, if one is present, except that priority 7
   SHOULD only be used for messages critical to establishing or
   maintaining adjacency and priority 6 SHOULD only be used for other
   important control messages.

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                           1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |    RBridge-Channel (0x8946)   |  0x0  | Channel Protocol=[TBD]|
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |          Flags        |  ERR  | SubERR| RESV4 | SType |  0x3  |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      / Security Information, variable length (0 length if SType = 0) /
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                             MacDA                             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |         MacDA (cont.)         |             MacSA             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                          MacSA (cont.)                        |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Any Ethernet frame tagging...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...
      |  Ethernet frame payload...
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-...

         Figure 3.4 Message Structure with Ethernet Frame Payload

   In the case of a non-Ethernet link, such as a PPP (Point-to-Point
   Protocol) link [RFC6361], the ports on the link are considered to
   have link-local synthetic 48-bit MAC addresses constructed as
   described below.  Such a constructed address MAY be used as a MacSA.
   If the RBridge Channel message is individually addressed to a link
   local port, the source TRILL switch will have the information to
   construct such a MAC address for the destination TRILL switch port
   and that MAC address MAY be used as the MacDA. By the use of such a
   MacSA and either such a unicast MacDA or a group addressed MacDA, an
   Ethernet frame can be sent between two TRILL switch ports connected
   by a non-Ethernet link.

   These synthetic TRILL switch port MAC addresses for non-Ethernet
   ports are constructed as follows: 0xFEFF, the nickname of the TRILL
   switch used in TRILL Hellos sent on that port, and the Port ID that
   the TRILL switch has assigned to that port, as shown in Figure 3.5.
   (Both the Port ID of the port on which a TRILL Hello is sent and the
   nickname of the sending TRILL switch appear in the Special VLANs and
   Flags sub-TLV [RFC7176] in TRILL IS-IS Hellos.)  The resulting MAC
   address has the Local bit on and the Group bit off [RFC7042].
   However, since there will be no Ethernet end stations on a non-
   Ethernet link in a TRILL campus, such synthetic MAC addresses cannot
   conflict on the link with a real Ethernet port address regardless of
   their value.

D. Eastlake, M. Umair, & Y. Li                                 [Page 12]
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                           1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            0xFEFF             |            Nickname           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |            Port ID            |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                     Figure 3.5 Synthetic MAC Address

D. Eastlake, M. Umair, & Y. Li                                 [Page 13]
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4. Extended RBridge Channel Security

   Table 4.1 below gives the assigned values of the SType (Security
   Type) field and their meaning. Use of DTLS Pairwise Security (SType =
   2) or Composite Security (SType = 3) is RECOMMENDED.

   While [RFC5310]-based authentication is also specified and can be
   used for both pairwise and multi-destination traffic, it provides
   only authentication and is not considered to meet current security
   standards. For example, it does not provide for key negotiation;
   thus, its use is NOT RECOMMENDED.

   The Extended RBridge Channel DTLS-based security specified in Section
   4.4 and the Composite Security specified in Section 4.5 below are
   intended for pairwise (known unicast) use. That is, the case where
   the M bit in the TRILL Header is zero and any Outer.MacDA is
   individually addressed.

   Multi-destination Extended RBridge Channel packets would be those
   with the M bit in the TRILL Header set to one or, in the native
   RBridge Channel case, the Outer.MacDA would be group addressed. The
   DTLS Pairwise Security and Composite Security STypes can also be used
   in the multi-destination case by serially unicasting the messages to
   all data-accessible RBridges (or stations in the native RBridge
   Channel case) in the recipient group. For TRILL Data packets, that
   group is specified by the Data Label; for native frames, the group is
   specified by the groupcast destination MAC address. It is intended to
   specify a true group keyed SType to secure multi-destination packets
   in a separate document [GroupKey].

      SType  Description                     Reference
      -----  -----------                     ---------
          0  None                            Section 4.2 of [this doc]
          1  [RFC5310]-Based Authentication  Section 4.3 of [this doc]
          2  DTLS Pairwise Security          Section 4.4 of [this doc]
          3  Composite Security              Section 4.5 of [this doc]
       4-14  Unassigned
         15  Reserved

                          Table 4.1 SType Values

4.1 Derived Keying Material

   In some cases, it is possible to use material derived from [RFC5310]
   IS-IS keying material as an element of Extended RBridge Channel
   security. It is assumed that the IS-IS keying material is of high
   quality. The material actually used is derived from the IS-IS keying
   material as follows:

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      Derived Material =
         HKDF-Expand-SHA256 ( IS-IS-key, "Extended Channel" | 0x0S, L )

   where "|" indicates concatenation, HKDF is as in [RFC5869], SHA256 is
   as in [RFC6234], IS-IS-key is the input IS-IS keying material,
   "Extended Channel" is the 16-character ASCII [RFC20] string indicated
   without any leading length byte or trailing zero byte, 0x0S is a
   single byte where S is the SType for which this key derivation is
   being used and the upper nibble is zero, and L is the length of the
   output-derived material needed.

   Whenever IS-IS keying material is being used as above, the underlying
   [RFC5310] keying material might expire or be invalidated. At the time
   of or before such expiration or invalidation, the use of the Derived
   Material from the IS-IS keying material MUST cease. Continued
   security MAY use new derived material from currently valid [RFC5310]
   keying material.

4.2 SType None

   No security services are being invoked. The length of the Security
   Information field (see Figure 2.4) is zero.

4.3 [RFC5310]-Based Authentication

   This SType provides security for Extended RBridge Channel messages
   similar to that provided for [IS-IS] PDUs by the [IS-IS]
   Authentication TLV.  The Security Information (see Figure 2.4) is as
   shown in Figure 4.1.

                                  1 1 1 1 1 1
              0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
             |  RESV |         Size          |
             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
             |           Key ID              |
             +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
             |                               |
             +
             | Authentication Data (Variable)
             +
             |
             +-+-+-+-+-+-+-+-+-+-+-+-+-...

                  Figure 4.1 SType 1 Security Information

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

   o  Size: Set to 2 + the size of Authentication Data in bytes.

   o  Key ID: specifies the keying value and authentication algorithm
      that the Key ID specifies for TRILL IS-IS LSP [RFC5310]
      Authentication TLVs. The keying material actually used is always
      derived as shown in Section 4.1.

   o  Authentication Data: The authentication data produced by the
      derived key and algorithm associated with the Key ID acting on the
      part of the TRILL Data packet shown. Length of the authentication
      data depends on the algorithm. The authentication value is
      included in the security information field and is treated as zero
      when authentication is calculated.

   As show in Figure 4.2, the area covered by this authentication starts
   with the byte immediately after the TRILL Header optional Flag Word
   if it is present. If the Flag Word is not present, it starts after
   the TRILL Header Ingress Nickname. In either case, it extends to just
   before the TRILL Data packet link trailer.  For example, for an
   Ethernet packet it would extend to just before the FCS.

         +-----------------------------+
         |  Link Header                |
         +-----------------------------+
         |  TRILL Header               |
         |  (plus optional flag word)  |
         +-----------------------------+   ^
         |  Inner Ethernet Addresses   |   |
         +-----------------------------+   .
         |  Data Label (VLAN or FGL)   |   |
         +-----------------------------+   .
         |  RBridge Channel Header     |   | <-authentication
         +-----------------------------+   .
         |  Extended Channel Header    |   |
         |  (plus Security Information)|   .
         +-----------------------------+   |
         |  Payload                    |   .
         +-----------------------------+   v
         |  Link Trailer               |
         +-----------------------------+

                Figure 4.2. SType 1 Authentication Coverage

   In the native RBridge Channel case this authentication coverage is as
   specified in the above paragraph except that it starts with the
   RBridge Channel Ethertype, since there is no TRILL Header, inner
   Ethernet addresses, or inner Data Label (see Figure 4.3).

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      +-----------------------------+
      |  Ethernet Header            |
      +-----------------------------+   ^
      |  RBridge Channel Header     |   |
      +-----------------------------+   .
      |  Extended Channel Header    |   | <-authentication
      |  (plus Security Information)|   .
      +-----------------------------+   |
      |  Payload                    |   .
      +-----------------------------+   v
      |  Ethernet Trailer           |
      +-----------------------------+

            Figure 4.3. Native SType 1 Authentication Coverage

   While RBridges, which are IS-IS routers, can reasonably be expected
   to hold [RFC5310] keying so that this SType can be used for RBridge
   Channel messages, how end stations might come to hold [RFC5310]
   keying is beyond the scope of this document. Thus this SType might
   not be applicable to native RBridge Channel messages.

4.4 DTLS Pairwise Security

   DTLS [RFC6347] supports key negotiation and provides both encryption
   and authentication. The RBridge Channel Extended Header DTLS Pairwise
   SType uses a negotiated DTLS version that MUST NOT be less than 1.2.

   When DTLS pairwise security is used, the entire payload of the
   Extended RBridge Channel packet, starting just after the null
   Security Information and ending just before the link trailer, is one
   or more DTLS records [RFC6347].  As specified in [RFC6347], DTLS
   records MUST be limited by the path MTU, in this case so each record
   fits entirely within a single Extended RBridge Channel message. A
   minimum path MTU can be determined from the TRILL campus minimum MTU
   Sz, which will not be less than 1470 bytes, by allowing for the TRILL
   Data packet, extended RBridge Channel, and DTLS framing overhead.
   With this SType, the security information between the extended
   RBridge Channel header and the payload is null because all the
   security information is in the payload area.

   The DTLS Pairwise keying is set up between a pair of RBridges
   independent of Data Label using messages of a priority configurable
   at the RBridge level which defaults to priority 6. DTLS message types
   other than application_data can be the payload of an extended RBridge
   Channel message with a TRILL Header using any Data Label and, for
   such DTLS message types, the PType in the RBridge Channel Header
   Extension is ignored.

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   Actual application_data sent within such a message using this SType
   SHOULD use the Data Label and priority as specified for that
   application_data.  In this case, the PType value in the RBridge
   Channel Header Extension applies to the decrypted application_data.

   TRILL switches that implement the extended RBridge Channel DTLS
   Pairwise SType SHOULD support the use of certificates for DTLS but
   certificate size may be limited by the DTLS requirement that each
   record fit within a single message. Appropriate certificate contents
   is out of scope for this document.

   TRILL switches that support the extended RBridge Channel DTLS
   Pairwise SType MUST support the use of pre-shared keys. If the
   psk_identity (see [RFC4279]) is two bytes, it is interpreted as a
   [RFC5310] Key ID and the value derived as shown in Section 4.1 from
   that key is used as a pre-shared key for DTLS negotiation. A
   psk_identity with a length other than two bytes MAY be used to
   indicate other implementation dependent pre-shared keys. Pre-shared
   keys used for DTLS negotiation SHOULD be shared only by the pair of
   end points; otherwise, security could be attacked by diverting
   messages to another end point holding that pre-shared key.

4.5 Composite Security

   Composite Security (SType = 3) is the combination of DTLS Pairwise
   Security and [RFC5310]-Based Authentication. On transmission, the
   DTLS record or records to be sent are secured as specified in Section
   4.4 then used as the payload for the application of Authentication as
   specified in Section 4.3. On reception, the [RFC5310]-based
   authentication is verified first and an error returned if it fails.
   If the [RFC5310]-based authentication succeeds, then the DTLS
   record(s) are processed.

   An advantage of Composite Security is that the payload is
   authenticated and encrypted with a modern security protocol and, in
   addition, the RBridge Channel Header and (except in the native case)
   preceding MAC addresses and Data Label are provided with some
   authentication.

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5. Extended RBridge Channel Errors

   RBridge Channel Header Extension errors are reported like RBridge
   Channel errors. The ERR field is set to one of the following error
   codes:

        Value    RBridge Channel Error Code Meaning
        -----   ------------------------------------
          6     Unknown or unsupported field value
          7     Authentication failure
          8     Error in nested RBridge Channel message

                      Table 5.1 Additional ERR Values

5.1 SubERRs

   If the ERR field is 6, the SubERR field indicates the problematic
   field or value as shown in the table below. At this time no suberrror
   codes are assigned under any other ERR field value.

        Err SubERR   Meaning (for ERR = 6)
        --- ------  -----------------------
         0          No Error, suberrors not allowed
        1-5         (no suberrors assigned)
         6     0    Reserved
         6     1    Non-zero RESV4 nibble
         6     2    Unsupported SType
         6     3    Unsupported PType
         6     4    Unknown Key ID
         6     5    Unsupported Ethertype with PType = 2
         6     6    Unsupported authentication algorithm for SType = 1
         6     7    Non-zero SubERR with zero ERR field
        7-14        (no suberrors assigned)
        15          (Reserved)

                          Table 5.2 SubERR values

5.2 Secure Nested RBridge Channel Errors

   If
      an extended RBridge Channel message is sent with security and with
      a payload type (PType) indicating an Ethertyped payload and the
      Ethertype indicates a nested RBridge Channel message
   and
      there is an error in the processing of that nested message that
      results in a return RBridge Channel message with a non-zero ERR

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      field,
   then that returned message SHOULD also be nested in an extended
   RBridge Channel message using the same type of security. In this
   case, the ERR field in the Extended RBridge Channel envelope is set
   to 8 indicating that there is a nested error in the message being
   tunneled back.

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6. IANA Considerations

   This section lists IANA Considerations.

6.1 Extended RBridge Channel Protocol Number

   IANA is requested to assign TBD [4 recommended] from the range
   assigned by Standards Action as the RBridge Channel protocol number
   to indicate RBridge Channel Header Extension.

   The added RBridge Channel protocols registry entry on the TRILL
   Parameters web page is as follows:

         Protocol    Description              Reference
         -------- -------------------------- ----------------
          TBD[4]   RBridge Channel Extension  [this document]

6.2 RBridge Channel Protocol Subregistries

   IANA is requested to create three subregistries under the "RBridge
   Channel Protocols" registry as in the subsections below.

6.2.1 RBridge Channel Error Codes

   IANA is requested to assign three additional code points in the
   "RBridge Channel Error Codes" registry on the TRILL Parameters web
   page. The additional entries are as show in Table 5.1 in Section 5
   and the "Reference" column value is "[this document]".

6.2.2 RBridge Channel SubError Codes

   IANA is request to create a subregistry indented under the RBridge
   Channel Error Codes registry, for RBridge Chanel SubError Code. The
   initial contents of this subregistry is as show in Table 5.2 in
   Section 5.1 except that a fourth column "Reference" is added with
   value "[this document]" for all rows. The header information is as
   follows:

      Registry Name: RBridge Channel SubError Codes
      Registration Procedures: IETF Review
      Reference: [this document]

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6.2.3 Extended RBridge Channel Payload Types Subregistry

   IANA is requested to create an "Extended RBridge Channel Payload
   Types" registry after the "RBridge Channel Protocols" registry on the
   TRILL Parameters web page. The header information is as follows:

      Registration Procedures: IETF Review
      Reference: [this document]

   The initial registry content is Table 3.1 in Section 3 of this
   document.

6.2.4 Extended RBridge Channel Security Types Subregistry

   IANA is requested to create an "Extended RBridge Channel Security
   Types" registry after the "Extended RBridge Channel Payload Types"
   registry on the TRILL Parameters web page. The header information is
   as follows:

      Registration Procedures: IETF Review
      Reference: [this document]

   The initial registry content is Table 4.1 in Section 4 of this
   document.

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7. Security Considerations

   The RBridge Channel Header Extension has potentially positive and
   negative effects on security.

   On the positive side, it provides optional security that can be used
   to authenticate and/or encrypt RBridge Channel messages. Some RBridge
   Channel message payloads, such as BFD [RFC7175], provide their own
   security but where this is not true, consideration should be given,
   when specifying an RBridge Channel protocol, to recommending or
   requiring use of the security features of the RBridge Channel Header
   Extension.

   On the negative side, the optional ability to tunnel more payload
   types and to tunnel them between TRILL switches and to and from end
   stations can increase risk unless precautions are taken.  The
   processing of decapsulated extended RBridge Channel payloads is a
   place where you SHOULD NOT be liberal in what you accept. This is
   because the tunneling facility makes it easier for unexpected
   messages to pop up in unexpected places in a TRILL campus due to
   accidents or the actions of an adversary. Local policies SHOULD
   generally be strict and only accept payload types required and then
   only with adequate security for the particular circumstances.

   See the first paragraph of Section 4 for recommendations on SType
   usage.

   See [RFC7457] for Security Considerations of DTLS for security.

   If IS-IS authentication is not being used, then [RFC5310] keying
   information would not normally be available but that presumably
   represents a judgment by the TRILL campus operator that no security
   is needed.

   See [RFC7178] for general RBridge Channel Security Considerations and
   [RFC6325] for general TRILL Security Considerations.

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Normative References

   [IS-IS] - ISO/IEC 10589:2002, Second Edition, "Information technology
         -- Telecommunications and information exchange between systems
         -- Intermediate System to Intermediate System intra-domain
         routeing information exchange protocol for use in conjunction
         with the protocol for providing the connectionless-mode network
         service (ISO 8473)", 2002.

   [RFC20] - Cerf, V., "ASCII format for network interchange", STD 80,
         RFC 20, DOI 10.17487/RFC0020, October 1969, <http://www.rfc-
         editor.org/info/rfc20>.

   [RFC2119] - BBradner, S., "Key words for use in RFCs to Indicate
         Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119,
         March 1997, <http://www.rfc-editor.org/info/rfc2119>.

   [RFC4279] - Eronen, P., Ed., and H. Tschofenig, Ed., "Pre-Shared Key
         Ciphersuites for Transport Layer Security (TLS)", RFC 4279, DOI
         10.17487/RFC4279, December 2005, <http://www.rfc-
         editor.org/info/rfc4279>.

   [RFC5310] - Bhatia, M., Manral, V., Li, T., Atkinson, R., White, R.,
         and M. Fanto, "IS-IS Generic Cryptographic Authentication", RFC
         5310, DOI 10.17487/RFC5310, February 2009, <http://www.rfc-
         editor.org/info/rfc5310>.

   [RFC5869] - Krawczyk, H. and P. Eronen, "HMAC-based Extract-and-
         Expand Key Derivation Function (HKDF)", RFC 5869, May 2010,
         <http://www.rfc-editor.org/info/rfc5869>.

   [RFC6325] - Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and A.
         Ghanwani, "Routing Bridges (RBridges): Base Protocol
         Specification", RFC 6325, DOI 10.17487/RFC6325, July 2011,
         <http://www.rfc-editor.org/info/rfc6325>.

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

   [RFC7172] - Eastlake 3rd, D., Zhang, M., Agarwal, P., Perlman, R.,
         and D. Dutt, "Transparent Interconnection of Lots of Links
         (TRILL): Fine-Grained Labeling", RFC 7172, DOI
         10.17487/RFC7172, May 2014, <http://www.rfc-
         editor.org/info/rfc7172>.

   [RFC7176] - Eastlake 3rd, D., Senevirathne, T., Ghanwani, A., Dutt,
         D., and A. Banerjee, "Transparent Interconnection of Lots of
         Links (TRILL) Use of IS-IS", RFC 7176, May 2014,
         <http://www.rfc-editor.org/info/rfc7176>.

D. Eastlake, M. Umair, & Y. Li                                 [Page 24]
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   [RFC7178] - Eastlake 3rd, D., Manral, V., Li, Y., Aldrin, S., and D.
         Ward, "Transparent Interconnection of Lots of Links (TRILL):
         RBridge Channel Support", RFC 7178, DOI 10.17487/RFC7178, May
         2014, <http://www.rfc-editor.org/info/rfc7178>.

   [RFC7356] - Ginsberg, L., Previdi, S., and Y. Yang, "IS-IS Flooding
         Scope Link State PDUs (LSPs)", RFC 7356, September 2014,
         <http://www.rfc-editor.org/info/rfc7356>.

   [RFC7780] - Eastlake 3rd, D., Zhang, M., Perlman, R., Banerjee, A.,
         Ghanwani, A., and S. Gupta, "Transparent Interconnection of
         Lots of Links (TRILL): Clarifications, Corrections, and
         Updates", RFC 7780, DOI 10.17487/RFC7780, February 2016,
         <http://www.rfc-editor.org/info/rfc7780>.

Informative References

   [RFC6234] - Eastlake 3rd, D. and T. Hansen, "US Secure Hash
         Algorithms (SHA and SHA-based HMAC and HKDF)", RFC 6234, DOI
         10.17487/RFC6234, May 2011, <http://www.rfc-
         editor.org/info/rfc6234>.

   [RFC6361] - Carlson, J. and D. Eastlake 3rd, "PPP Transparent
         Interconnection of Lots of Links (TRILL) Protocol Control
         Protocol", RFC 6361, August 2011

   [RFC7042] - Eastlake 3rd, D. and J. Abley, "IANA Considerations and
         IETF Protocol and Documentation Usage for IEEE 802 Parameters",
         BCP 141, RFC 7042, October 2013.

   [RFC7067] - Dunbar, L., Eastlake 3rd, D., Perlman, R., and I.
         Gashinsky, "Directory Assistance Problem and High-Level Design
         Proposal", RFC 7067, DOI 10.17487/RFC7067, November 2013,
         <http://www.rfc-editor.org/info/rfc7067>.

   [RFC7175] - Manral, V., Eastlake 3rd, D., Ward, D., and A. Banerjee,
         "Transparent Interconnection of Lots of Links (TRILL):
         Bidirectional Forwarding Detection (BFD) Support", RFC 7175,
         May 2014.

   [RFC7457] - Sheffer, Y., Holz, R., and P. Saint-Andre, "Summarizing
         Known Attacks on Transport Layer Security (TLS) and Datagram
         TLS (DTLS)", RFC 7457, February 2015, <http://www.rfc-
         editor.org/info/rfc7457>.

   [AddrFlush] - W. Hao, D. Eastlake, Y. Li, "TRILL: Address Flush
         Message", draft-ietf-trill-address-flush, work in progress.

D. Eastlake, M. Umair, & Y. Li                                 [Page 25]
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   [GroupKey] - D. Eastlake et al, "Group Keying Protocol", draft-
         eastlake-trill-group-keying, work in progress.

   [rfc6439bis] - D. Eastlake, Y. Li, M. Umair, A. Banerjee, H. Fangwei,
         "TRILL: Appointed Forwarders", draft-ietf-trill-rfc6439bis,
         work in progress.

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Appendix Z: Change History

   RFC Editor: Please delete this Appendix before publication.

From -00 to -01

   1. Fix references for RFCs published, etc.

   2. Explicitly mention in the Abstract and Introduction that this
      document updates [RFC7178].

   3. Add this Change History Appendix.

From -01 to -02

   1. Remove section on the "Scope" feature as mentioned in
      http://www.ietf.org/mail-archive/web/trill/current/msg06531.html

   2. Editorial changes to IANA Considerations to correspond to draft-
      leiba-cotton-iana-5226bis-11.txt.

   3. Improvements to the Ethernet frame payload type.

   4. Other Editorial changes.

From -02 to -03

   1. Update TRILL Header to correspond to [RFC7780].

   2. Remove a few remnants of the "Scope" feature that was removed from
      -01 to -02.

   3. Substantial changes to and expansion of Section 4 including adding
      details of DTLS security.

   4. Updates and additions to the References.

   5. Other minor editorial changes.

   From -03 to -04

   1. Add SType for [RFC5310] keying based security that provides
      encryption as well as authentication.

   2. Editorial improvements and fixes.

From -04 to -05

   1. Primary change is collapsing the previous PTypes 2, 3, and 4 for
      RBridge Channel message, TRILL Data, and TRILL IS-IS into one by

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      including the Ethertype. Previous PType 5 is renumbered as 3.

   2. Add Channel Tunnel Crypto Suites to IANA Considerations

   3. Add some material to Security Considerations,

   4. Assorted Editorial changes.

From -05 to -06

   Fix editorials found during WG Last Call.

From -06 to -07

   Minor editorial changes resulting for Shepherd review.

From -07 to -08

   Move group keyed security out of the draft. Simplify and improve
   remaining security provisions.

From -08 to -09

   1. Updates based on Routing Directorate review.

   2. Improvements to specification of pairwise DTLS and significant
      other security improvements.

From -09 to -10

   Update based on GENART review.

From -10 to -11

   1. Add IANA registry for suberror codes and make other minor IANA
      Considerations changes.

   2. Add informational references to [RFC7067], address flush, and
      rfc6439bis.

   3. Add RFC 2119 keyword emphasis to Security Considerations caution
      in handling decapsulated extended RBridge Channel payloads.

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Acknowledgements

   The contributions of the following are hereby gratefully
   acknowledged:

         Stephen Farrell, Jonathan Hardwick, Susan Hares, Gayle Noble,
         Alvaro Retana, Yaron Sheffer, and Peter Yee.

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

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Authors' Addresses

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

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

      Mohammed Umair
      IPinfusion

      EMail: mohammed.umair2@gmail.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

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors. All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document. Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document. Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.  The definitive version of
   an IETF Document is that published by, or under the auspices of, the
   IETF. Versions of IETF Documents that are published by third parties,
   including those that are translated into other languages, should not
   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
   translated into other languages, should not be considered to be
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   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
   from or are inconsistent with the rights and licenses granted under
   RFC 5378, shall have any effect and shall be null and void, whether
   published or posted by such Contributor, or included with or in such
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D. Eastlake, M. Umair, & Y. Li                                 [Page 31]