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INTERNET-DRAFT                                               D. Eastlake
Intended Status: Proposed Standard                Futurewei Technologies
Expires: November 13, 2020                                  May 14, 2020


      MAC Address for Layer 3 Link Local Discovery Protocol (LLDP)
                    <draft-eastlake-lldp-mac-00.txt>


Abstract

   IEEE 802 has defined a number of protocols which operate between
   adjacent Ethernet stations at Layer 2, including bridges, such as the
   Link Layer Discover Protocol (IEEE 802.1AB, LLDP). LLDP and other
   such protocols may be useful between Layer 3 aware stations such as
   IP routers and hosts. This document specifies a MAC address that can
   be used for this purpose despite intervening bridges.



Status of This Memo

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D. Eastlake                                                     [Page 1]


INTERNET-DRAFT                                       L3 LLDP MAC Address


Table of Contents

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

      2. Network Layers and MAC Addresses........................4

      3. IANA Considerations.....................................6
      4. Security Considerations.................................7

      5. Acknowledgements........................................7

      Normative References.......................................8
      Informative References.....................................8

      Appendix A: EUI-48 Assignment Request.....................10




































D. Eastlake                                                     [Page 2]


INTERNET-DRAFT                                       L3 LLDP MAC Address


1. Introduction

   IEEE 802 [IEEE802] has defined a number of protocols which operate
   between adjacent Ethernet stations at Layer 2, including bridges,
   such as the Link Layer Discover Protocol ([802.1AB] LLDP) and the
   Link Aggregation Control Protocol ([802.1AX] LACP). LLDP and other
   such protocols may be useful between adjacent Layer 3 [ISO] aware
   stations such as IP routers and hosts. This document specifies a MAC
   address that can be used for that purpose despite intervening
   bridges.



1.1 Notations Used in This Document

   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.

   In this document the terms/acronyms listed below have the indicated
   meaning:

   "LACP"   Link Aggregation Control Protocol [802.1AX].

   "Layer 2"  Layer 2 in the ISO model [ISO].

   "Layer 3"  Layer 3 in the ISO model [ISO].

   "LLDP"   Link Layer Discovery Protocol [802.1AB].

   "MAC"    Media Access Control [RFC7042bis] (not Message
            Authentication Code).

   PDU      Protocol Data Unit.
















D. Eastlake                                                     [Page 3]


INTERNET-DRAFT                                       L3 LLDP MAC Address


2. Network Layers and MAC Addresses

   LLDP [802.1AB] is a Layer 2 [ISO] protocol providing for the
   unacknowledged announcement of information by an Ethernet station to
   other stations on the same Ethernet link.  There are proposals for
   the use of LLDP between L3 aware stations such as between a host and
   its first hop IP router or between IP adjacent routers. Examples are
   [LLDP1] [LLDP2] [LLDP3]. In addition, project [802.1ABdh] is underway
   in [IEEE802] that may extend the LLDP standard so that stations can
   announce a larger amount of information.

   As illustrated in the figure below, uses of LLDP and similar
   protocols between Ethernet stations have a scope of adjacency
   controlled by the multicast destination MAC address [RFC7042bis] of
   the Ethernet frame used to transmit the LLDP PDU.

    - Customer bridges use 0x0180C2000000 for LLDP and the like. Frames
      sent to that address are transparently forwarded through any lower
      level bridges, such as the provider bridges shown below. On the
      other hand, IP routers do not forward frames sent to unknown
      multicast addresses unless configured to do so. Thus, frames sent
      to this address by the customer bridge shown near the bottom of
      the figure will not reach either of the customer bridges shown
      higher up in the figure due to the intervening IP router.

    - Provider bridges use 0x0180C2000008 for LLDP. Frames sent to that
      address are transparently forwarded by lower level bridges (not
      shown in the figure) and are blocked by higher level bridges, such
      as customer bridges. They are also blocked as described in the
      previous point by IP routers.


   LLDP or similar Ethernet frames intended to be between adjacent IP
   routers or between a host and its first hop IP router need to avoid
   use of a destination MAC address that might be intercepted by any
   intervening bridge. The multicast destination MAC addresses used by
   bridges are the block from 0x0180C2000000 to 0x0180C200003F but it
   would be best to be conservative and avoid all addresses from
   0x0180C2000000 to 0x0180C2FFFFFF.  An address meeting this criterion
   is specified in Section 3 below and its use is RECOMMENDED.












D. Eastlake                                                     [Page 4]


INTERNET-DRAFT                                       L3 LLDP MAC Address


          +-------+
          |  Host |
          +-------+
              |
         +---------+
         |L3 Router|
         +---------+
              .     \
              .      +---------------+
              .      |Customer Bridge|
              .      +---------------+
              .              :        \
              .              :         +---------------+
              .              :         |Provider Bridge|
              .              :         +---------------+
              .              :                |
              .              :         +---------------+
              .              :         |Provider Bridge|
              .              :         +---------------+
              .              :        /
              .      +---------------+
              .      |Customer Bridge|
              .      +---------------+
              .     /
         +---------+
         |L3 Router|
         +---------+
              .     \
              .      +---------------+
              .      |Customer Bridge|
              .      +---------------+
              .     /
          +-------+
          |  Host |
          +-------+

   Note: The above figure is simplified. For example, where one or two
   customer bridges or provider bridges are shown, there could be zero
   or some larger number. There could also be one or more bridges
   between the host shown at the top of the figure and its first hop IP
   router. Only two levels of bridge are shown (customer and provider)
   but [802.1Q] specifies additional levels of bridges.










D. Eastlake                                                     [Page 5]


INTERNET-DRAFT                                       L3 LLDP MAC Address


3. IANA Considerations

   IANA is requested to assign a 48-bit multicast MAC address
   [0x00000E900004 suggested] under the IANA OUI for use with Link Layer
   Discovery Protocol and similar protocols between Layer 3 routers as
   per the request in Appendix A. The entry in the "IANA Multicast
   48-bit MAC Addresses" registry is as follows:

      Addresses   Usage                      Reference
      ---------  -------------------------  ---------------
       [tbd]     Layer 3 LLDP and the like  [this document]

   (Alternatively, there could be more than on MAC address assigned for
   different L3 or higher layer [ISO] purposes.)






































D. Eastlake                                                     [Page 6]


INTERNET-DRAFT                                       L3 LLDP MAC Address


4. Security Considerations

   TBD



5. Acknowledgements

   The comments and suggestions of the following people, listed in
   alphabetic order, are gratefully acknowledged:

      TBD








































D. Eastlake                                                     [Page 7]


INTERNET-DRAFT                                       L3 LLDP MAC Address


Normative References

   [802.1AB] - IEEE 802, "IEEE Standard for Local and metropolitan area
         networks - Station and Media Access Control Connectivity
         Discovery", IEEE Std 802.1AB-2016, 29 January 2016.

   [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>.

   [RFC7042bis] - 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, <http://www.rfc-editor.org/info/rfc7042>.

   [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>.



Informative References

   [802.1ABdh] - IEEE 802, "IEEE Standard for Local and Metropolitan
         Area Networks - Station and Media Access Control Connectivity
         Discovery Amendment: Support for Multiframe Protocol Data
         Units", work in progress.

   [802.1AX] - IEEE 802, "IEEE Standard for Local and metropolitan area
         networks - Link Aggregation", IEEE Std 802.1AX-2014, 10
         December 2014.

   [802.1Q] - IEEE 802, "IEEE Standard for Local and metropolitan area
         networks - Bridges and Bridged Networks", IEEE Std 802.1Q-2014,
         3 November 2014.

   [IEEE802] - IEEE 802 LAN/MAN Standards Committee,
         <http://www.ieee802.org>.

   [ISO] - ISO/IEC, "Information technology - Open Systems
         Interconnection - Basic Reference Model: The Basic Model",
         ISO/IEC 7498-1:1994(E), 15 June 1996.

   [LLDP1] - A. Lindem, K. Patel, S. Zandi, J. Haas, X. Xu, "BGP Logical
         Link Discovery Protocol (LLDP) Peer Discovery", draft-acee-idr-
         lldp-peer-discovery, work in progress.

   [LLDP2] - P. Congdon, P. Bottorff, "LSVR IETF Organizationally
         Specific TLVs for IEEE Std 802.1AB (LLDP)", draft-congdon-lsvr-
         lldp-tlvs, work in progress.


D. Eastlake                                                     [Page 8]


INTERNET-DRAFT                                       L3 LLDP MAC Address


   [LLDP3] - M. Richardson, L. Xia, "IPv6 over Link-Local Discovery
         Protocol", draft-richardson-anima-ipv6-lldp, work in progress.


















































D. Eastlake                                                     [Page 9]


INTERNET-DRAFT                                       L3 LLDP MAC Address


Appendix A: EUI-48 Assignment Request

   (not yet submitted)

   Applicant Name: Donald E. Eastlake, III

   Applicant Email: d3e3e3@gmail.com

   Applicant Telephone: +1-508-333-2270

   Use Name: L3-LLDP

   Document: [this document]

   Specify whether this is an application for EUI-48 or EUI-64
   identifiers: EUI-48

   Size of Block requested: 1

   Specify multicast, unicast, or both: multicast
































D. Eastlake                                                    [Page 10]


INTERNET-DRAFT                                       L3 LLDP MAC Address


Authors' Addresses

      Donald E. Eastlake 3rd
      Futurewei Technologies
      2386 Panoramic Circle
      Apopka, FL 32703 USA

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











































D. Eastlake                                                    [Page 11]


INTERNET-DRAFT                                       L3 LLDP MAC Address


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   submitted in full conformance with the provisions of BCP 78 and BCP
   79.




































D. Eastlake                                                    [Page 12]


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