Network Working Group P. Johansson
Internet-Draft Congruent Software, Inc.
<draft-ietf-ip1394-ipv4-04.txt>
Expires: April, 1998
Ipv4 over IEEE 1394
STATUS OF THIS DOCUMENT
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its areas, and
its working groups. Note that other groups may also distribute working
documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference material
or to cite them other than as "work in progress."
To view the entire list of current Internet-Drafts, please check the
"1id-abstracts.txt" listing contained in the Internet-Drafts Shadow
Directories on ftp.is.co.za (Africa), ftp.nordu.net (Europe),
munnari.oz.au (Pacific Rim), ds.internic.net (US East Coast), or
ftp.isi.edu (US West Coast).
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 code for that purpose and additionally
defines a standard method for Address Resolution Protocol (ARP).
Expires: April, 1998 [Page 1]
Internet-Draft 04 Ipv4 over 1394 October 1997
TABLE OF CONTENTS
1. INTRODUCTION.......................................................3
2. DEFINITIONS AND NOTATION...........................................4
2.1 Conformance....................................................4
2.2 Glossary.......................................................4
2.3 Abbreviations..................................................5
3. IP-CAPABLE NODES...................................................5
4. LINK ENCAPSULATION AND FRAGMENTATION...............................6
5. ARP................................................................6
6. IP UNICAST.........................................................8
6.1 Asynchronous IP unicast........................................9
6.2 Isochronous IP unicast........................................10
7. IP BROADCAST......................................................10
8. IP MULTICAST......................................................10
9. SECURITY CONSIDERATIONS...........................................10
10. ACKNOWLEDGEMENTS.................................................10
11. REFERENCES.......................................................10
12. EDITOR担 ADDRESS.................................................11
Expires: April, 1998 [Page 2]
Internet-Draft 04 Ipv4 over 1394 October 1997
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 a standard method for Address Resolution Protocol (ARP).
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 implements communications between nodes
over shared physical media at speeds that range from 100 to 400 Mbps.
Both consumer electronic applications (such as digital VCR痴, 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.
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痴 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
to the control and status registers (CSR痴) in this area usually have
side effects. Registers 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 ID's are
variable and subject to reassignment each time one or more nodes are
added or removed from the bus.
The 1394 link layer provides a datagram service with both confirmed
(acknowledged) and unconfirmed datagrams. The confirmed datagram service
is called "asynchronous" while the unconfirmed service is known as
"isochronous." Other than the presence or absence of confirmation, the
principal distinction between the two is quality of service: isochronous
datagrams are guaranteed to be delivered with bounded latency. Datagram
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).
Expires: April, 1998 [Page 3]
Internet-Draft 04 Ipv4 over 1394 October 1997
NOTE: Extensions underway in IEEE P1394b contemplate additional speeds
of 800, 1600 and 3200 Mbps; engineering prototypes are planned for early
1998.
2. DEFINITIONS AND NOTATION
2.1 Conformance
Several keywords are used to differentiate levels of requirements and
optionality, 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, octlets or
fields whose values are not checked by the recipient.
may: A keyword that indicates flexibility of choice with no implied
preference.
reserved: A keyword used to describe objects-bits, octets, quadlets,
octlets and fields-or the code values assigned to these objects in cases
where either the object or the code value is set aside for future
standardization. Usage and interpretation may be specified by future
extensions to this or other standards. A reserved object shall be zeroed
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 a defined object shall check its value and
reject reserved code values.
shall: A keyword that indicates a mandatory requirement. Designers are
required to implement all such mandatory requirements to assure
interoperability with other products conforming to this standard.
should: A keyword that denotes flexibility of choice with a strongly
preferred alternative. Equivalent to the phrase "is recommended."
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 bridged buses. The bus ID is the most significant portion of
a node's 16-bit node ID.
IP datagram: An Internet message that conforms to the format specified
by RFC 791.
link fragment: A portion of an IP datagram transmitted within a single
1394 packet. The data payload of the 1394 packet contains both a link
Expires: April, 1998 [Page 4]
Internet-Draft 04 Ipv4 over 1394 October 1997
fragment header and its associated link fragment. It is possible to
transmit datagrams without fragmentation.
link fragment header: A structure that precedes all IP datagrams (or
each fragment thereof) when they are transmitted over 1394. See also
link fragment.
local bus ID: A bus ID with the value 0x3FF. A node shall respond to
transaction requests addressed to its 6-bit physical ID if the bus ID in
the request is either 0x3FF or a bus ID explicitly assigned to the node.
node ID: A 16-bit number that uniquely identifies a Serial Bus node .
The most significant 10 bits are the bus ID and the least significant 6
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 1394 packets from ARP or IP
datagrams, which are also (generically) packets.
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.
2.3 Abbreviations
The following are abbreviations that are used in this standard:
ARP Address resolution protocol
CSR Control and status register
CRC Cyclical redundancy checksum
EUI-64 Extended Unique Identifier, 64-bits (essentially equivalent to
names used elsewhere, such as global unique ID or world-wide
unique ID)
IP Internet protocol (within the context of this document, IPv4)
3. IP-CAPABLE NODES
Expires: April, 1998 [Page 5]
Internet-Draft 04 Ipv4 over 1394 October 1997
Not all 1394 devices are capable of the reception and transmission of
ARP or IP datagrams. An IP-capable node shall fulfill the following
minimum 1394 requirements:
- the max_rec field in its bus information block shall be at least 8;
this indicates an ability to accept write requests 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 response
packet with a data payload of 512 octets;
4. LINK ENCAPSULATION AND FRAGMENTATION
All IP datagrams (broadcast, unicast or multicast), as well as ARP
requests and responses, that are transferred via 1394 block write
requests or stream packets shall be encapsulated within the packet's
data payload. The maximum size of data payload, in octets, is
constrained by the speed at which the packet is transmitted.
Table 1 - Maximum data payloads
Speed Asynchronous Isochronous
+------------------------------------+
| S100 | 512 | 1024 |
| S200 | 1024 | 2048 |
| S400 | 2048 | 4096 |
| S800 | 4096 | 8192 |
| S1600 | 8192 | 16384 |
| S3200 | 16384 | 32768 |
+------------------------------------+
The maximum data payload may also be restricted by the capabilities of
the sending or receiving node; this is specified by max_rec in the bus
information block.
For either of these reasons, the minimum capabilities between any two
IP-capable nodes may be less than the 2024 octet MTU specified by this
document. This necessitates 1394 link level fragmentation of IP
datagrams, which provides for the ordering and reassembly of link
fragments when necessary.
NOTE: The working group has arrived at rough consensus that link
encapsulation and fragmentation shall be utilized for all IP datagrams.
The details of the headers necessary have yet to be determined. As a
consequence, the remainder of section 6 has been deleted from this
revision of the working draft; the deleted text has not been marked by
change bars.
5. ARP
ARP datagrams shall be transmitted by the same means as broadcast IP
datagrams. The data payload of an Address Resolution Protocol (ARP)
datagram is 56 octets and shall conform to the format illustrated below.
Expires: April, 1998 [Page 6]
Internet-Draft 04 Ipv4 over 1394 October 1997
NOTE: The contents of the ARP datagram are agreed but its exact format
remains subject to change.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 0 | reserved | ether_type (0x0806) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| hardware_type (0x0018) | protocol_type (0x0800) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| hw_addr_len | IP_addr_len | opcode |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+--- sender_unique_ID ---+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sender_node_ID | sender_unicast_FIFO_hi |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sender_unicast_FIFO_lo |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sender_max_rec| reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sender_IP_address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+--- target_unique_ID ---+
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| target_node_ID | target_unicast_FIFO_hi |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| target_unicast_FIFO_lo |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| target_max_rec| reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| target_IP_address |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4 - ARP datagram format
Field usage in an ARP datagram is as follows:
hardware_type: This field indicates 1394 and shall have a value of
0x0018.
protocol_type: This field shall have a value of 0x0800; this
indicates that the protocol addresses in the ARP request or response
conform to the format for IP addresses.
hw_addr_len: This field indicates the size, in octets, of the 1394-
dependent hardware address associated with an IP address and shall
have a value of 20.
Expires: April, 1998 [Page 7]
Internet-Draft 04 Ipv4 over 1394 October 1997
IP_addr_len: This field indicates the size, in octets, of an IP
version 4 (IPv4) address and shall have a value of 4.
opcode: This field shall be one to indicate an ARP request and two to
indicate an ARP response.
sender_unique_ID: This field shall contain the node_unique_ID of the
sender and shall be equal to that specified in the sender's bus
information block.
sender_node_ID: This field shall contain the most significant 16 bits
of the sender's NODE_IDS register.
sender_unicast_FIFO_hi and sender_unicast_FIFO_lo: These fields
together shall specify the 48-bit offset of the sender's FIFO
available for the receipt of IP datagrams in the format specified by
section 6. The offset of a sender's unicast FIFO shall not change,
either as a result of a bus reset, power reset or other circumstance,
unless the new FIFO offset is advertised by an unsolicited ARP
response datagram.
sender_max_rec: This field shall be equal to the value of max_rec in
the sender痴 configuration ROM bus information block.
sender_IP_address: This field shall specify the IP address of the
sender.
target_unique_ID: In an ARP request, this field shall be all ones. In
an ARP response, it shall be set to the value of sender_unique_ID
from the corresponding ARP request.
target_node_ID: In an ARP request, this field shall be all ones. In
an ARP response, it shall be set to the value of sender_node_ID from
the corresponding ARP request.
target_unicast_FIFO_hi and target_unicast_FIFO_lo: In an ARP request,
these fields shall be all ones. In an ARP response, they shall be set
to the value of sender_unicast_FIFO_hi and sender_unicast_FIFO_lo
from the corresponding ARP request.
target_max_rec: In an ARP request, this field shall be zero. In an
ARP response, it shall be equal to the value of max_rec from the
corresponding ARP request.
target_IP_address: In an ARP request, this field shall specify the IP
address from which the responder desires a response. In an ARP
response, it shall be set to the value of sender_IP_address from the
corresponding ARP request.
6. IP UNICAST
IP unicast may be transmitted to a recipient within a 1394 primary
packet that has one of the following transaction codes:
Expires: April, 1998 [Page 8]
Internet-Draft 04 Ipv4 over 1394 October 1997
tcode Description Arbitration
+--------------------------------------+
| 0x01 | Block write | Asynchronous |
| 0x0A | Stream packet | Isochronous |
| 0x0A | Stream packet | Asynchronous |
+--------------------------------------+
Block write requests are suitable when 1394 link-level acknowledgement
of the datagram is desired but there is no need for bounded latency in
the delivery of the packet (quality of service).
Isochronous stream packets provide quality of service guarantees but not
1394 link-level acknowledgement.
The last method, asynchronous stream packets, is mentioned only for the
sake of completeness. This method should not be used, since it provides
for neither 1394 link-level acknowledgment nor quality of service---and
consumes a valuable resource, a channel number.
NOTE: Regardless of the IP unicast method employed, asynchronous or
isochronous, it is the responsibility of the sender of a unicast IP
datagram to determine the maximum data payload that may be used in each
packet. The necessary information may be obtained from:
- the SPEED_MAP maintained by the 1394 bus manager and provides a
maximum transmission speed between any two nodes on the local
Serial Bus. The speed in turn implies a maximum data payload (see
Table 1).
NOTE: The SPEED_MAP is derived from the self-ID packets transmitted by
all 1394 nodes subsequent to a bus reset. An IP-capable node may observe
the self-ID packets directly;
- the target_max_rec field in an ARP response. This document requires
a minimum value of 8 (equivalent to a data payload of 512 octets).
Nodes that operate at S200 and faster are encouraged but not
required to implement correspondingly larger values for
target_max_rec; or
- other methods beyond the scope of this standard.
The maximum data payload shall be the minimum of the largest data
payload implemented by the sender, the recipient and the PHYs of all
intervening nodes.
6.1 Asynchronous IP unicast
Unicast IP datagrams that do not require any quality of service shall be
contained within the data payload of 1394 block write transactions
addressed to the target_node_ID and target_unicast_FIFO obtained from an
ARP response packet.
Expires: April, 1998 [Page 9]
Internet-Draft 04 Ipv4 over 1394 October 1997
If no acknowledgement is received in response to a unicast block write
request, the state of the target is ambiguous.
NOTE: An acknowledgment may be absent because the target is no longer
functional, may not have received the packet because of a header CRC
error or may have received the packet successfully but the acknowledge
sent in response was corrupted.
6.2 Isochronous IP unicast
Unicast IP datagrams that require quality of service shall be contained
within the data payload of 1394 isochronous stream packets.
The details of coordination between nodes with respect to allocation of
channel number(s) and bandwidth is beyond the scope of this standard.
7. IP BROADCAST
The 1394 facilities, whether asynchronous stream packets or block write
requests with a destination_ID of 0xFFFF, have yet to be determined by
the working group.
The use of asynchronous streams for IP broadcast requires some method
for the allocation of a channel number and the communication of this
channel number to all IP-capable nodes. The method has yet to be agreed
by the working group.
On the other hand, if block write requests with a destination_ID of
0xFFFF are used, it will be necessary to propose a fixed 48-bit
destination_offset to IEEE P1394a.
8. IP MULTICAST
Many of the details of multicast remain outside the scope of this draft
in its present form (but are expected to be added by the working group
as the draft is advanced).
IP multicast shall use stream packets, either asynchronous or
isochronous, according to the quality of service required.
9. SECURITY CONSIDERATIONS
This document raises no security issues.
10. ACKNOWLEDGEMENTS
This document represents work in progress by the IP / 1394 Working
Group. The editor wishes to acknowledge the contributions made by all
the active participants, either on the reflector or at face-to-face
meetings, which have advanced the technical content.
11. REFERENCES
[1] IEEE Std 1394-1995, Standard for a High Performance Serial Bus
Expires: April, 1998 [Page 10]
Internet-Draft 04 Ipv4 over 1394 October 1997
[2] ISO/IEC 13213:1994, Control and Status Register (CSR) Architecture
for Microcomputer Buses
[3] IEEE Project P1394a, Draft Standard for a High Performance Serial
Bus (Supplement)
[4] IEEE Project P1394b, Draft Standard for a High Performance Serial
Bus (Supplement)
12. EDITOR担 ADDRESS
Peter Johansson
Congruent Software, Inc.
3998 Whittle Avenue
Oakland, CA 94602
(510) 531-5472
(510) 531-2942 FAX
pjohansson@aol.com
Expires: April, 1998 [Page 11]