Browse Prior Art Database

Standard for the transmission of IP datagrams and ARP packets over ARCNET networks (RFC1051) Disclosure Number: IPCOM000001858D
Original Publication Date: 1988-Mar-01
Included in the Prior Art Database: 2000-Sep-12
Document File: 3 page(s) / 7K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

P.A. Prindeville: AUTHOR


This RFC specifies a standard method of encapsulating Internet Protocol (IP) [1] and Address Resolution Protocol (ARP) [2] datagrams on an ARCNET [3].

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 39% of the total text.

Network Working Group P. Prindeville

Request for Comments: 1051 McGill University

March 1988

A Standard for the Transmission of IP Datagrams

and ARP Packets over ARCNET Networks

Status of this Memo

This RFC specifies a standard protocol for the Internet community.

Distribution of this memo is unlimited.


This RFC specifies a standard method of encapsulating Internet

Protocol (IP) [1] and Address Resolution Protocol (ARP) [2] datagrams

on an ARCNET [3].


The author wishes to express thanks to Robert Craig of the McGill

University Computing Centre and Bruce Hughes of Datapoint Corporation

for their generous support of facilities and information. I also

extend my gratitude to the readers of the PCIP mailing list for their

helpful ideas and comments.

Frame Format

IP and ARP datagrams are transmitted in standard ARCNET packets. As

required by Datapoint Corporation, the first octet of the data field

is reserved for the network layer protocol identification (the

"system code" in Datapoint nomenclature), and must contain the value

240 (F0 hex) for IP or 241 (F1 hex) for ARP. The ARP hardware

address type for ARCNET is 7 [9].

ARCNET supports packet formats containing 1-253 octets of data

(normal format) and 257-508 octets of data (extended format),

inclusive of system code. Note that there exists a range of data

lengths (254-256) which are 'forbidden'. IP packets within this

range should be padded (with octets of zero) to meet the minimum

extended packet size of 257 data octets. This padding is not part of

the IP packet and is not included in the total length field of the IP


On networks where some hosts do not support extended packet format,

the IP Maximum Transmission Unit (MTU) should be set to 253, though

implementors are encouraged to support the extended packet format

mode of operation.

Because the ARCNET maximum packet length is less than the Internet

default MTU, implementations are strongly encouraged to support IP

level fragmentation and reassembly. Hosts not supporting this should

take steps to discourage others from sending fragmented packets, such

as using the TCP Maximum Segment Size option [4].

The frame format is:

Normal Packet Extended Packet

+----------------+ +----------------+

| ALERT* | | ALERT* |

+----------------+ ...