rfc2734.txt

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Network Working Group                                       P. Johansson
Request for Comments: 2734                      Congruent Software, Inc.
Category: Standards Track                                  December 1999


                          IPv4 over IEEE 1394

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 (1999).  All Rights Reserved.

ABSTRACT

   This document specifies how to use IEEE Std 1394-1995, Standard for a
   High Performance Serial Bus (and its supplements), for the transport
   of Internet Protocol Version 4 (IPv4) datagrams; it defines the
   necessary methods, data structures and codes for that purpose. These
   include not only packet formats and encapsulation methods for
   datagrams, but also an address resolution protocol (1394 ARP) and a
   multicast channel allocation protocol (MCAP). Both 1394 ARP and MCAP
   are specific to Serial Bus; the latter permits management of Serial
   Bus resources when used by IP multicast groups.

TABLE OF CONTENTS

   1. INTRODUCTION.....................................................2
   2. DEFINITIONS AND NOTATION.........................................4
      2.1 Conformance..................................................4
      2.2 Glossary.....................................................4
      2.3 Abbreviations................................................6
      2.4 Numeric values...............................................6
   3. IP-CAPABLE NODES.................................................6
   4. LINK ENCAPSULATION AND FRAGMENTATION.............................7
      4.1 Global asynchronous stream packet (GASP) format..............8
      4.2 Encapsulation header.........................................9
      4.3 Link fragment reassembly....................................11
   5. SERIAL BUS ADDRESS RESOLUTION PROTOCOL (1394 ARP)...............11
   6. CONFIGURATION ROM...............................................14
      6.1 Unit_Spec_ID entry..........................................14
      6.2 Unit_SW_Version entry.......................................14



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RFC 2734                  IPv4 over IEEE 1394              December 1999


      6.3 Textual descriptors.........................................15
   7. IP UNICAST......................................................16
   8. IP BROADCAST....................................................17
   9. IP MULTICAST....................................................17
      9.1 MCAP message format.........................................18
      9.2 MCAP message domain.........................................21
      9.3 Multicast receive...........................................21
      9.4 Multicast transmit..........................................22
      9.5 Advertisement of channel mappings...........................23
      9.6 Overlapped channel mappings.................................23
      9.7 Transfer of channel ownership...............................24
      9.8 Redundant channel mappings..................................25
      9.9 Expired channel mappings....................................25
      9.10 Bus reset..................................................26
   10. IANA CONSIDERATIONS............................................26
   11. SECURITY CONSIDERATIONS........................................27
   12. ACKNOWLEDGEMENTS...............................................27
   13. REFERENCES.....................................................28
   14. EDITOR'S ADDRESS...............................................28
   15. Full Copyright Statement.......................................29

1. INTRODUCTION

   This document specifies how to use IEEE Std 1394-1995, Standard for a
   High Performance Serial Bus (and its supplements), for the transport
   of Internet Protocol Version 4 (IPv4) datagrams. It defines the
   necessary methods, data structures and codes for that purpose and
   additionally defines methods for an address resolution protocol (1394
   ARP) and a multicast channel allocation protocol (MCAP)---both of
   which are specific to Serial Bus.

   The group of IEEE standards and supplements, draft or approved,
   related to IEEE Std 1394-1995 is hereafter referred to either as 1394
   or as Serial Bus.

   1394 is an interconnect (bus) that conforms to the CSR architecture,
   ISO/IEC 13213:1994. Serial Bus permits communications between nodes
   over shared physical media at speeds that range, at present, from 100
   to 400 Mbps. Both consumer electronic applications (such as digital
   VCRs, stereo systems, televisions and camcorders) and traditional
   desktop computer applications (e.g., mass storage, printers and
   tapes), have adopted 1394. Serial Bus is unique in its relevance to
   both consumer electronic and computer domains and is EXPECTED to form
   the basis of a home or small office network that combines both types
   of devices.






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RFC 2734                  IPv4 over IEEE 1394              December 1999


   The CSR architecture describes a memory-mapped address space that
   Serial Bus implements as a 64-bit fixed addressing scheme. Within the
   address space, ten bits are allocated for bus ID (up to a maximum of
   1,023 buses), six are allocated for node physical ID (up to 63 per
   bus) while the remaining 48 bits (offset) describe a per node address
   space of 256 terabytes. The CSR architecture, by convention, splits a
   node's address space into two regions with different behavioral
   characteristics. The lower portion, up to but not including 0xFFFF
   F000 0000, is EXPECTED to behave as memory in response to read and
   write transactions. The upper portion is more like a traditional IO
   space: read and write transactions in this area usually have side
   effects. Control and status registers (CSRs) that have FIFO behavior
   customarily are implemented in this region.

   Within the 64-bit address, the 16-bit node ID (bus ID and physical
   ID) is analogous to a network hardware address---but 1394 node IDs
   are variable and subject to reassignment each time one or more nodes
   are added to or removed from the bus.

   NOTE: Although the 16-bit node ID contains a bus ID, at present there
   is no standard method to connect separately enumerated Serial Buses.
   Active development of a standard for Serial Bus to Serial Bus bridges
   is underway in the IEEE P1394.1 working group. Unless extended by
   some future standard, the IPv4 over 1394 protocols specified by this
   document may not operate correctly across bridges.

   The 1394 link layer provides a packet delivery service with both
   confirmed (acknowledged) and unconfirmed packets. Two levels of
   service are available: "asynchronous" packets are sent on a best-
   effort basis while "isochronous" packets are guaranteed to be
   delivered with bounded latency. Confirmed packets are always
   asynchronous but unconfirmed packets may be either asynchronous or
   isochronous. Data payloads vary with implementations and may range
   from one octet up to a maximum determined by the transmission speed
   (at 100 Mbps, named S100, the maximum asynchronous data payload is
   512 octets while at S400 it is 2048 octets).

   NOTE: Extensions underway in IEEE P1394b contemplate additional
   speeds of 800, 1600 and 3200 Mbps.












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RFC 2734                  IPv4 over IEEE 1394              December 1999


2. DEFINITIONS AND NOTATION

2.1 Conformance

   When used in this document, the keywords "MAY", "OPTIONAL",
   "RECOMMENDED", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD" and "SHOULD
   NOT" differentiate levels of requirements and optionality and are to
   be interpreted as described in RFC 2119.

   Several additional keywords are employed, as follows:

   EXPECTED: A keyword used to describe the behavior of the hardware or
   software in the design models assumed by this standard. Other
   hardware and software design models may also be implemented.

   IGNORED: A keyword that describes bits, octets, quadlets or fields
   whose values are not checked by the recipient.

   RESERVED: A keyword used to describe either objects---bits, octets,
   quadlets and fields---or the code values assigned to these objects;
   the object or the code value is set aside for future standardization.
   A RESERVED object has no defined meaning and SHALL be zeroed by its
   originator or, upon development of a future standard, set to a value
   specified by such a standard. The recipient of a RESERVED object
   SHALL NOT check its value. The recipient of an object whose code
   values are defined by this standard SHALL check its value and reject
   RESERVED code values.

2.2 Glossary

   The following terms are used in this standard:

   address resolution protocol: A method for a requester to determine
   the hardware (1394) address of an IP node from the IP address of the
   node.

   bus ID: A 10-bit number that uniquely identifies a particular bus
   within a group of multiple interconnected buses. The bus ID is the
   most significant portion of a node's 16-bit node ID. The value 0x3FF
   designates the local bus; a node SHALL respond to requests addressed
   to its 6-bit physical ID if the bus ID in the request is either 0x3FF
   or the bus ID explicitly assigned to the node.

   encapsulation header: A structure that precedes all IP data
   transmitted over 1394. See also link fragment.

   IP datagram: An Internet message that conforms to the format
   specified by STD 5, RFC 791.



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RFC 2734                  IPv4 over IEEE 1394              December 1999


   link fragment: A portion of an IP datagram transmitted within a
   single 1394 packet. The data payload of the 1394 packet contains both
   an encapsulation header and its associated link fragment. It is
   possible to transmit datagrams without link fragmentation.

   multicast channel allocation protocol: A method for multicast groups
   to coordinate their use of Serial Bus resources (channels) if
   multicast datagrams are transmitted on other than the default
   broadcast channel.

   multicast channel owner: A multicast source that has allocated a
   channel for one or more multicast addresses and transmits MCAP
   advertisements to communicate these channel mapping(s) to other
   participants in the IP multicast group. When more than one source
   transmits MCAP advertisements for the same channel number, the source
   with the largest physical ID is the owner.

   node ID: A 16-bit number that uniquely identifies a Serial Bus node
   within a group of multiple interconnected buses. The most significant
   ten bits are the bus ID and the least significant six bits are the
   physical ID.

   node unique ID: A 64-bit number that uniquely identifies a node among
   all the Serial Bus nodes manufactured worldwide; also known as the
   EUI-64 (Extended Unique Identifier, 64-bits).

   octet: Eight bits of data.

   packet: Any of the 1394 primary packets; these may be read, write or
   lock requests (and their responses) or stream data. The term "packet"
   is used consistently to differentiate Serial Bus primary packets from
   1394 ARP requests/responses, IP datagrams or MCAP
   advertisements/solicitations.

   physical ID: On a particular bus, this 6-bit number is dynamically
   assigned during the self-identification process and uniquely
   identifies a node on that bus.

   quadlet: Four octets, or 32 bits, of data.

   stream packet: A 1394 primary packet with a transaction code of 0x0A
   that contains a block data payload. Stream packets may be either
   asynchronous or isochronous according to the type of 1394 arbitration
   employed.







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RFC 2734                  IPv4 over IEEE 1394              December 1999


2.3 Abbreviations

   The following are abbreviations that are used in this standard: