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rfc:rfc8381

Internet Engineering Task Force (IETF) D. Eastlake 3rd Request for Comments: 8381 Y. Li Category: Standards Track W. Hao ISSN: 2070-1721 Huawei

                                                           A. Banerjee
                                                                 Cisco
                                                              May 2018
       Transparent Interconnection of Lots of Links (TRILL):
              Vendor-Specific RBridge Channel Protocol

Abstract

 The IETF TRILL (Transparent Interconnection of Lots of Links)
 protocol is implemented by devices called TRILL switches or RBridges
 (Routing Bridges).  TRILL includes a general mechanism, called an
 RBridge Channel, for the transmission of typed messages between
 RBridges in the same campus and between RBridges and end stations on
 the same link.  This document specifies a method to send vendor-
 specific messages over the RBridge Channel facility.

Status of This Memo

 This is an Internet Standards Track document.
 This document is a product of the Internet Engineering Task Force
 (IETF).  It represents the consensus of the IETF community.  It has
 received public review and has been approved for publication by the
 Internet Engineering Steering Group (IESG).  Further information on
 Internet Standards is available in Section 2 of RFC 7841.
 Information about the current status of this document, any errata,
 and how to provide feedback on it may be obtained at
 https://www.rfc-editor.org/info/rfc8381.

Eastlake, et al. Standards Track [Page 1] RFC 8381 TRILL: Vendor Channel May 2018

Copyright Notice

 Copyright (c) 2018 IETF Trust and the persons identified as the
 document authors.  All rights reserved.
 This document is subject to BCP 78 and the IETF Trust's Legal
 Provisions Relating to IETF Documents
 (https://trustee.ietf.org/license-info) in effect on the date of
 publication of this document.  Please review these documents
 carefully, as they describe your rights and restrictions with respect
 to this document.  Code Components extracted from this document must
 include Simplified BSD License text as described in Section 4.e of
 the Trust Legal Provisions and are provided without warranty as
 described in the Simplified BSD License.

Table of Contents

 1. Introduction ....................................................2
    1.1. Terminology and Acronyms ...................................3
 2. Vendor Channel Packet Format ....................................3
 3. Vendor Channel Errors ...........................................6
    3.1. Sending an Error Response ..................................7
 4. IANA Considerations .............................................9
 5. Security Considerations .........................................9
 6. References .....................................................10
    6.1. Normative References ......................................10
    6.2. Informative References ....................................10
 Authors' Addresses ................................................11

1. Introduction

 The IETF TRILL (Transparent Interconnection of Lots of Links)
 protocol [RFC6325] [RFC7780] is implemented by devices called TRILL
 switches or RBridges (Routing Bridges).  It provides efficient least-
 cost transparent routing in multi-hop networks with arbitrary
 topologies and link technologies, using link-state routing and a hop
 count.
 The TRILL protocol includes an RBridge Channel facility [RFC7178] to
 support typed message transmission between RBridges in the same
 campus and between RBridges and end stations on the same link.  This
 document specifies a method of sending messages specified by a
 particular organization, indicated by OUI (Organizationally Unique
 Identifier) [RFC7042] or CID (Company Identifier) [802], over the
 RBridge Channel facility.  Such organization-specific messages could,
 for example, be used for vendor-specific diagnostic or control
 messages.

Eastlake, et al. Standards Track [Page 2] RFC 8381 TRILL: Vendor Channel May 2018

 However, note that a range of RBridge Channel protocol numbers are
 available based on RFC publication.  Those intending to use the
 RBridge Channel facility are encouraged to document their use in an
 RFC and to use RBridge Channel protocol numbers based on such RFC
 publication.

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
 BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
 capitals, as shown here.
 This document uses the acronyms defined in [RFC6325] supplemented by
 the following additional acronyms:
 CID - Company Identifier [802]
 FGL - Fine-Grained Labeling
 OUI - Organizationally Unique Identifier [RFC7042]
 TRILL switch - An alternative term for an RBridge

2. Vendor Channel Packet Format

 The general structure of an RBridge Channel packet on a link between
 TRILL switches (RBridges) is shown in Figure 1 below.  When an
 RBridge Channel message is sent between an RBridge and an end station
 on the same link, in either direction, it is called a Native RBridge
 Channel message and the TRILL Header (including the Inner Ethernet
 Addresses and Data Label area) is omitted as shown in Figure 2.  The
 type of RBridge Channel packet is given by a Protocol field in the
 RBridge Channel Header that indicates how to interpret the Channel-
 Protocol-Specific Payload.  See [RFC7178].

Eastlake, et al. Standards Track [Page 3] RFC 8381 TRILL: Vendor Channel May 2018

                           Packet Structure
                 +-----------------------------------+
                 |           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 1: RBridge Channel Packet Structure
                           Message Structure
                 +-----------------------------------+
                 |           Link Header             |
                 +-----------------------------------+
                 |      RBridge Channel Header       |
                 +-----------------------------------+
                 | Channel Protocol Specific Payload |
                 +-----------------------------------+
                 |    Link Trailer (FCS if Ethernet) |
                 +-----------------------------------+
          Figure 2: Native RBridge Channel Message Structure
 Figure 3 below expands the RBridge Channel Header and Channel
 Protocol Specific Payload above for the case of the Vendor-Specific
 RBridge Channel Tunnel Protocol.  0x8946 is the Ethertype [RFC7042]
 assigned by the IEEE for the RBridge Channel protocol.

Eastlake, et al. Standards Track [Page 4] RFC 8381 TRILL: Vendor Channel May 2018

                         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
  RBridge Channel Header:
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |    RBridge-Channel (0x8946)   |  0x0  | Channel Protocol=0x008|
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |          Flags        |  ERR  |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  RBridge Channel Protocol Specific:
                                    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                    |     Vendor ID = OUI/CID       |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |OUI/CID (cont.)|     VERR      | Sub-Protocol  | Sub-Version   |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |            Vendor-Protocol-Specific Data
    |
    |  ...
              Figure 3: Channel Tunnel Message Structure
 The fields in Figure 3 related to the Vendor RBridge Channel Protocol
 are as follows:
    Channel Protocol:  The RBridge Channel Protocol value allocated
       for the Vendor Channel (see Section 4).
    Vendor ID: This field indicates the vendor specifying the
       particular use or uses of the Vendor Channel.  The vendor to
       whom the OUI or CID in this field has been allocated is in
       charge of specifying Vendor Channel messages using their
       identifier.  Depending on the first byte of this field as
       follows:
       OUI: When the bottom two bits of the first byte of the Vendor
          ID are zero (that is, the first byte is 0bXXXXXX00), the
          Vendor ID is an OUI.
       CID: When the bottom two bits of the first byte are a one
          followed by a zero (that is, the first byte is 0bXXXXXX10),
          the Vendor ID is a CID.
       Other: Other values of the bottom two bits of the first byte of
          the Vendor ID are invalid, and a VERR of 2 MUST be returned,
          subject to possible rate limiting (see Section 3).
    VERR:  Vendor Channel Error.  See Section 3.

Eastlake, et al. Standards Track [Page 5] RFC 8381 TRILL: Vendor Channel May 2018

    Sub-Protocol: Actually, the vendor specifying their use of the
       Vendor Channel can do whatever they want with the bits after
       the VERR field.  But it is strongly RECOMMENDED that they use
       the sub-protocol / sub-version fields indicated so that
       multiple and evolving uses can be specified based on a single
       OUI.
    Sub-Version: See explanation above of the Sub-Protocol field.
       This field is provided to indicate the version of the
       particular vendor's Sub-Protocol.

3. Vendor Channel Errors

 The VERR field values from 0x0 through 0x0F (inclusive) and the value
 0xFF are reserved for specification by the IETF.  See Section 4.  All
 other values of VERR are available for whatever use the vendor
 specifies, except that a Vendor Channel implementation MUST NOT send
 a Vendor Channel Error in response to a Vendor Channel message with a
 nonzero VERR.
 The VERR values thus far specified by the IETF are as follows:
 0.  The VERR field is zero in Vendor Channel messages unless the
     Vendor Channel packet is reporting an error.
 1.  The value one indicates that the length of the RBridge-Channel-
     Specific Data is less than 4 bytes.  This means that at least the
     VERR byte and possibly part or all of the OUI is truncated.  If
     an RBridge that implements the Vendor Channel facility receives
     such a Vendor Channel message, it MUST expand it to extend
     through the VERR field, set that field to one, and return the
     packet as described in Section 3.1.
 2.  The OUI/CID field value is unknown.  If an RBridge implements the
     Vendor Channel facility and receives a Vendor Channel packet with
     a zero VERR field and an OUI/CID field it does not recognize and
     the SL flag is zero in the RBridge Channel Header, it MUST set
     the VERR field to the value two and return the packet as
     described in Section 3.1.

Eastlake, et al. Standards Track [Page 6] RFC 8381 TRILL: Vendor Channel May 2018

 3.  The value 3 indicates that the Sub-Protocol field value is
     unknown.  An RBridge SHOULD set the VERR field to 3 and return
     the packet as described in Section 3.1 if it implements the
     Vendor Channel facility and it receives a Vendor Channel packet
     meeting the following conditions:
     (a) a zero VERR field in the RBridge Channel Header,
     (b) a zero SL flag in the RBridge Channel Header,
     (c) an OUI/CID that it implements, and
     (d) a Sub-Protocol field value it does not recognize even though
         it implements and uses the Sub-Protocol field.
 4.  The value 4 indicates that the Sub-Version field value is
     unknown.  An RBridge SHOULD set the VERR field to 4 and return
     the packet as described in Section 3.1 if it implements the
     Vendor RBridge Channel facility and it receives a Vendor Channel
     packet meeting the following conditions:
     (a) a zero VERR field  in the RBridge Channel Header,
     (b) a zero SL flag in the RBridge Channel Header,
     (c) an OUI/CID and Sub-Protocol that it implements, and
     (d) a Sub-Version field value it does not recognize even though
         it implements and uses the Sub-Version field.
 Uniform error handling is generally advisable for the sake of
 maintenance and understandability; however, "SHOULD" is chosen for
 errors 3 and 4 above because, as long as each message is
 distinguished by a vendor's OUI/CID, it is up to that vendor to
 decide between standard and nonstandard error handling.

3.1. Sending an Error Response

 The IETF-specified Vendor Channel errors are sent in response to a
 received RBridge Channel packet by setting the VERR field as
 specified above and modifying the packet as specified below.  (The
 ERR field will be zero because, if it were nonzero, the packet would
 have been handled at the general RBridge Channel level rather than
 being passed down to the Vendor Channel level.)
 The RBridge Channel Header is modified by setting the SL flag.  (The
 flags in the Channel Header and the semantics of the SL flag are
 specified in [RFC7178].)
 o  If an error 1 is being generated because of truncation, the
    RBridge-Channel-Specific Data area is extended to include the VERR
    byte.

Eastlake, et al. Standards Track [Page 7] RFC 8381 TRILL: Vendor Channel May 2018

 o  If a Vendor Channel message was sent between RBridges, the TRILL
    Header is modified by (1) clearing the M bit, (2) setting the
    egress nickname to the ingress nickname as received, (3) setting
    the ingress nickname to a nickname held by the TRILL switch
    sending the error packet, and (4) setting the hop count to the
    usual value on TRILL Data packets used by the TRILL switch sending
    the error packet.
 o  If a Vendor Channel message was sent between an RBridge and an end
    station in either direction, the outer MAC addresses are modified
    by (1) setting the Outer.MacDA to the Outer.MacSA as received and
    (2) setting the Outer.MacSA to the MAC address of the port of the
    TRILL switch or end station sending the error packet.
 o  The priority of the error response message MAY be reduced from the
    priority of the Vendor Chanel message causing the error, unless it
    was already minimum priority, and the Drop Eligibility Indicator
    bit MAY be set in an error response.  (See Section 4.1.1 of
    [RFC6325].)
 o  Vendor Channel error responses MAY be rate-limited.
 It is generally anticipated that the entire packet in which an error
 was detected would be sent back, modified as above, as the protocol
 specific payload, so that, for example, error responses could more
 easily be matched with messages sent; however, except for errors 1
 and 2, this is up to the vendor specifying how their Vendor RBridge
 Channel messages are to be used.
 Note that if you receive a Vendor Channel error message with error 1,
 indicating a truncation error, you cannot trust the apparent
 "OUI/CID" in that Vendor Channel error message.

Eastlake, et al. Standards Track [Page 8] RFC 8381 TRILL: Vendor Channel May 2018

4. IANA Considerations

 IANA has allocated 0x008 for the Vendor-Specific RBridge Channel
 Protocol from the range of RBridge Channel protocols allocated by
 Standards Action.
 IANA has established a subregistry as follows in the TRILL Parameters
 registry (indented under "RBridge Channel Error Codes" after "RBridge
 Channel SubError Codes"):
 Registry: Vendor RBridge Channel Error Codes
 Registration Procedures: Standards Action
 Reference: RFC 8381
        Code      Description                     Reference
        ----      -----------                     ---------
        0x00      No error                        RFC 8381
        0x01      Message too short               RFC 8381
        0x02      Unknown OUI/CID                 RFC 8381
        0x03      Unknown Sub-Protocol            RFC 8381
        0x04      Unknown Sub-Version             RFC 8381
       0x05-0x0F  Unassigned                      -
       0x10-0xFE  Reserved for vendor use         RFC 8381
        0xFF      Reserved                        RFC 8381

5. Security Considerations

 See [RFC6325] for general TRILL Security Considerations.
 See [RFC7178] for general RBridge Channel Security Considerations.
 Neither the Vendor-Specific RBridge Channel Protocol nor the basic
 RBridge Channel Protocol [RFC7178] provide any security assurances or
 features.  (The basic RBridge Channel Protocol's first use was as an
 envelope for Bidirectional Forwarding Detection (BFD) messages
 [RFC7175], which provide their own security.)  Any needed security
 can be provided by fields or processing within the Vendor-Protocol-
 Specific Data, which is outside the scope of this document.
 Alternatively or in addition, use of a Vendor Channel MAY be nested
 inside the RBridge Channel Header Extension Protocol [RFC7978]; this
 can provide some security services.

Eastlake, et al. Standards Track [Page 9] RFC 8381 TRILL: Vendor Channel May 2018

6. References

6.1. Normative References

 [802]      IEEE 802, "IEEE Standard for Local and Metropolitan Area
            Networks: Overview and Architecture",
            DOI 10.1109/IEEESTD.2014.6847097, IEEE Std 802-2014.
 [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
            Requirement Levels", BCP 14, RFC 2119,
            DOI 10.17487/RFC2119, March 1997,
            <https://www.rfc-editor.org/info/rfc2119>.
 [RFC6325]  Perlman, R., Eastlake 3rd, D., Dutt, D., Gai, S., and A.
            Ghanwani, "Routing Bridges (RBridges): Base Protocol
            Specification", RFC 6325, DOI 10.17487/RFC6325, July 2011,
            <https://www.rfc-editor.org/info/rfc6325>.
 [RFC7042]  Eastlake 3rd, D. and J. Abley, "IANA Considerations and
            IETF Protocol and Documentation Usage for IEEE 802
            Parameters", BCP 141, RFC 7042, DOI 10.17487/RFC7042,
            October 2013, <https://www.rfc-editor.org/info/rfc7042>.
 [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,
            <https://www.rfc-editor.org/info/rfc7178>.
 [RFC7780]  Eastlake 3rd, D., Zhang, M., Perlman, R., Banerjee, A.,
            Ghanwani, A., and S. Gupta, "Transparent Interconnection
            of Lots of Links (TRILL): Clarifications, Corrections, and
            Updates", RFC 7780, DOI 10.17487/RFC7780, February 2016,
            <https://www.rfc-editor.org/info/rfc7780>.
 [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
            2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
            May 2017, <https://www.rfc-editor.org/info/rfc8174>.

6.2. Informative References

 [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, DOI 10.17487/RFC7175, May 2014,
            <https://www.rfc-editor.org/info/rfc7175>.

Eastlake, et al. Standards Track [Page 10] RFC 8381 TRILL: Vendor Channel May 2018

 [RFC7978]  Eastlake 3rd, D., Umair, M., and Y. Li, "Transparent
            Interconnection of Lots of Links (TRILL): RBridge Channel
            Header Extension", RFC 7978, DOI 10.17487/RFC7978,
            September 2016, <https://www.rfc-editor.org/info/rfc7978>.

Authors' Addresses

 Donald Eastlake 3rd
 Huawei Technologies
 155 Beaver Street
 Milford, MA  01757
 United States of America
 Phone: +1-508-333-2270
 EMail: d3e3e3@gmail.com
 Yizhou Li
 Huawei Technologies
 101 Software Avenue,
 Nanjing 210012
 China
 Phone: +86-25-56622310
 Email: liyizhou@huawei.com
 Weiguo Hao
 Huawei Technologies
 101 Software Avenue,
 Nanjing 210012
 China
 Phone: +86-25-56623144
 Email: haoweiguo@huawei.com
 Ayan Banerjee
 Cisco
 Email: ayabaner@cisco.com

Eastlake, et al. Standards Track [Page 11]

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