rfc3146.txt

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Network Working Group                                        K. Fujisawa
Request for Comments: 3146                                       A. Onoe
Category: Standards Track                               Sony Corporation
                                                            October 2001


          Transmission of IPv6 Packets over IEEE 1394 Networks

Status of this Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

Abstract

   This document describes the frame format for transmission of IPv6
   packets and the method of forming IPv6 link-local addresses and
   statelessly autoconfigured addresses on IEEE1394 networks.

1. INTRODUCTION

   IEEE Std 1394-1995 (and its amendment) 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.






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RFC 3146          IPv6 Packets over IEEE 1394 Networks      October 2001


3. IPv6-CAPABLE NODES

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

   -  it MUST implement configuration ROM in the general format
      specified by ISO/IEC 13213:1994 and MUST implement the bus
      information block specified by IEEE Std 1394a-2000 [1394a] and a
      unit directory specified by this document;

   -  the max_rec field in its bus information block MUST 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 MUST also apply to read requests; that is, the node
      MUST be able to transmit a block response packet with a data
      payload of 512 octets;

   -  it MUST be isochronous resource manager capable, as specified by
      IEEE Std 1394a-2000;

   -  it MUST support both reception and transmission of asynchronous
      streams as specified by IEEE Std 1394a-2000.

4. LINK ENCAPSULATION AND FRAGMENTATION

   The encapsulation and fragmentation mechanism MUST be the same as "4.
   LINK ENCAPSULATION AND FRAGMENTATION" of [IP1394].

      Note: Since there is an ether_type field to discriminate protocols
      and MCAP (multicast channel allocation protocol) is used for both
      IPv4 and IPv6, the version field in GASP (global asynchronous
      stream packet) header of IPv6 datagrams is the same value (one) as
      [IP1394].

   The ether_type value for IPv6 is 0x86dd.

   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.







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RFC 3146          IPv6 Packets over IEEE 1394 Networks      October 2001


5. CONFIGURATION ROM

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

   - The value for Unit_SW_Version is 0x000002.

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

      Note: A dual-stack (IPv4 and IPv6) node will have two unit
      directories for IPv4 and IPv6 respectively.

6. STATELESS AUTOCONFIGURATION

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

   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



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RFC 3146          IPv6 Packets over IEEE 1394 Networks      October 2001


   conjunction with the content of the Source link-layer address.  An
   implementation MAY use some other methods to obtain a node_ID of the
   sender utilizing a mapping table between node_unique_ID (EUI-64
   identifier) and node_ID.  The mechanism to make such mapping table is
   out of scope of this document.

   The recipient of an Neighbor Discovery packet MUST 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 (EUI-64 identifier)         |
   +---                            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                               |    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).

   node_unique_ID  This field contains the node unique ID of the
                   node and MUST be equal to that specified in the
                   node's configuration ROM.

   max_rec         This field MUST be equal to the value of max_rec
                   in the node's configuration ROM.

   spd             This field MUST be set to the lesser of the node's
                   link speed and PHY speed.  The link speed is the
                   maximum speed at which the link may send or
                   receive packets; the PHY speed is the maximum
                   speed at which the PHY may send, receive or repeat
                   packets.  The encoding used for spd is specified in
                   the Table 2 of [IP1394].



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