Internet-Draft                                               K. Fujisawa
<draft-fujisawa-ip1394-ipv6-04.txt>                     Sony Corporation
Expires: December, 2000                                        June 2000

          Transmission of IPv6 Packets over IEEE 1394 Networks

Status of this memo

     This document is an Internet-Draft and is in full conformance
     with all provisions of Section 10 of RFC2026.

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Abstract

   IEEE Std 1394-1995 is a standard for a High Performance Serial Bus.
   This document describes the frame format for transmission of IPv6
   [IPV6] packets and the method of forming IPv6 link-local addresses
   and statelessly autoconfigured addresses on IEEE1394 networks.
   It also describes the content of the Source/Target Link-layer Address
   option used in Neighbor Discovery [DISC] when the messages are
   transmitted on an IEEE1394 network.














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1. INTRODUCTION

   IEEE Std 1394-1995 is a standard for a High Performance Serial Bus.
   IETF IP1394 Working Group has standardized the method to carry IPv4
   datagrams and ARP packets over IEEE1394 subnetwork [IP1394].

   This document describes the frame format for transmission of IPv6
   [IPV6] packets and the method of forming IPv6 link-local addresses
   and statelessly autoconfigured addresses on IEEE1394 networks.
   It also describes the content of the Source/Target Link-layer Address
   option used in Neighbor Discovery [DISC] when the messages are
   transmitted on an IEEE1394 network.

2. SPECIFICATION TERMINOLOGY

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

3. IPv6-CAPABLE NODES

   An IPv6-capable node SHALL fulfill the following minimum
   requirements:

   - it SHALL implement configuration ROM in the general format
     specified by ISO/IEC 13213:1994 and SHALL implement the bus
     information block specified by IEEE P1394a [P1394a] and a unit
     directory specified by this document;

   - the max_rec field in its bus information block SHALL be at least 8;
     this indicates an ability to accept block write requests and
     asynchronous stream packets with data payload of 512 octets. The
     same ability SHALL also apply to read requests; that is, the node
     SHALL be able to transmit a block response packet with a data
     payload of 512 octets;

   - it SHALL be isochronous resource manager capable, as specified by
     IEEE P1394a;

   - it SHALL support both reception and transmission of asynchronous
     streams as specified by IEEE P1394a.

4. LINK ENCAPSULATION AND FRAGMENTATION

   The encapsulation and fragmentation mechanism SHOULD be the same
   as "5. LINK ENCAPSULATION AND FRAGMENTATION" of [IP1394].

   The ether_type value for IPv6 is 0x86dd.



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   The default MTU size for IPv6 packets on an IEEE1394 network is 1500
   octets.  This size may be reduced by a Router Advertisement [DISC]
   containing an MTU option which specifies a smaller MTU, or by manual
   configuration of each node.  If a Router Advertisement received on
   an IEEE1394 interface has an MTU option specifying an MTU larger than
   1500, or larger than a manually configured value, that MTU option may
   be logged to system management but MUST be otherwise ignored. The
   mechanism to extend MTU size between particular two nodes is for
   further study.

5. CONFIGURATION ROM

   Configuration ROM for IPv6-capable nodes SHALL contain a unit
   directory in the format specified by [IP1394] except following rules.

   - The value for Unit_SW_Version is TBD.

   - The textual descriptor for the Unit_SW_Version SHOULD be "IPv6".

6. STATELESS AUTOCONFIGURATION

   The Interface Identifier [AARCH] for an IEEE1394 interface is formed
   from the interface's built-in EUI-64 by complementing the
   "Universal/Local" (U/L) bit, which is the next-to-lowest order bit of
   the first octet of the EUI-64.  Complementing this bit will generally
   change a 0 value to a 1, since an interface's built-in address is
   expected to be from a universally administered address space and
   hence have a globally unique value.  A universally administered EUI-
   64 is signified by a 0 in the U/L bit position, while a globally
   unique IPv6 Interface Identifier is signified by a 1 in the
   corresponding position. For further discussion on this point, see
   [AARCH].

   An IPv6 address prefix used for stateless autoconfiguration [ACONF]
   of an IEEE1394 interface MUST have a length of 64 bits.

7. LINK-LOCAL ADDRESSES

   The IPv6 link-local address [AARCH] for an IEEE1394 interface is
   formed by appending the Interface Identifier, as defined above, to
   the prefix FE80::/64.

       10 bits            54 bits                  64 bits
     +----------+-----------------------+----------------------------+
     |1111111010|         (zeros)       |    Interface Identifier    |
     +----------+-----------------------+----------------------------+

8. ADDRESS MAPPING FOR UNICAST



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   The procedure for mapping IPv6 unicast addresses into IEEE1394 link-
   layer addresses uses the Neighbor Discovery [DISC].  Since 1394 link
   address (node_ID) will not be constant across a 1394 bridge, we have
   chosen not to put it in the Link-layer Address option.  The recipient
   of the Neighbor Discovery SHOULD use the source_ID (obtained from
   either the asynchronous packet header or the GASP header) in
   conjunction with the content of the Source link-layer address.
   The recipient of an Neighbor Discovery packet SHOULD ignore it unless
   the most significant ten bits of the source_ID are equal to either
   0x3FF or the most significant ten bits of the recipient's NODE_IDS
   register.

   The Source/Target Link-layer Address option has the following form
   when the link layer is IEEE1394.

                         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
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |     Type      |  Length = 3   |                               |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                            ---+
     |                         node_unique_ID                        |
     +---                            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                               |    max_rec    |      spd      |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                          unicast_FIFO                         |
     +---                            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                               |            reserved           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     |                            reserved                           |
     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type        1 for Source Link-layer address.
               2 for Target Link-layer address.

   Length      3 (in units of 8 octets).

   The meaning of 'node_unique_ID', 'unicast_FIFO', 'max_rec' and 'spd'
   sub-fields are specified in [IP1394].

   Note that node_ID may change when 1394 bus-reset occurs. The mapping
   cache held in the node SHOULD be cleared on 1394 bus-reset.

9. IPv6 MULTICAST

   By default, all best-effort IPv6 multicast SHALL use asynchronous
   stream packets whose channel number is equal to the channel field
   from the BROADCAST_CHANNEL register.




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   Best-effort IPv6 multicast for particular multicast group addresses
   may utilize a different channel number if such a channel number is
   allocated and advertised prior to use, by a multicast channel
   allocation protocol (MCAP), as described in [IP1394].  The
   implementors are encouraged to support this protocol when
   transmitting high-rate multicast streams.  The MCAP 'type' value for
   IPv6 group address descriptor is TBD.

10. OPEN ISSUES

   a) The mechanism to extend MTU size between particular two nodes.

   b) The mechanism to allocate and distribute a 1394 isochronous
      channel number for isochronous transmission of IPv6 packets,
      for an unicast or multicast flow.

Security Considerations

   Security issues are not discussed in this document.

Acknowledgment

   The editor would like to acknowledge the author of [ETHER] since some
   part of this document has been derived from [ETHER].

References

    [1394]   IEEE Std 1394-1995, Standard for a High Performance Serial
             Bus

    [P1394a] IEEEE P1394a Draft Standard for a High Performance Serial
             Bus (Amendment)

    [IP1394] Johansson, P., "IPv4 over IEEE 1394", RFC 2734, December
             1999.

    [IPV6]   S. Deering, R. Hinden, "Internet Protocol, Version 6 (IPv6)
             Specification", RFC2460, Dec 1998.

    [AARCH]  R. Hinden, S. Deering "IP Version 6 Addressing
             Architecture", RFC2373.

    [ACONF]  S. Thomson, T. Narten, "IPv6 Stateless Address
             Autoconfiguration", RFC2462, Dec 1998.

    [DISC]   T. Narten, E. Nordmark, W. A. Simpson, "Neighbor Discovery
             for IP Version 6 (IPv6)", RFC2461, Dec 1998.




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    [ETHER]  M. Crawford, "Transmission of IPv6 Packets over Ethernet
             Networks", RFC2464, Dec 1998.

Author's address

   Kenji Fujisawa
   Sony Corporation
   6-7-35, Kitashinagawa,
   Shinagawa-ku, Tokyo, 141-0001 Japan
   Phone: +81-3-5795-8507
   E-mail: fujisawa@sm.sony.co.jp








































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