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Transmitting IP traffic over ARCNET networks (RFC1201)

IP.com Disclosure Number: IPCOM000002015D
Original Publication Date: 1991-Feb-01
Included in the Prior Art Database: 2000-Sep-12
Document File: 6 page(s) / 16K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

D. Provan: AUTHOR

Abstract

This memo specifies a method of encapsulating Internet Protocol (IP) [1] and Address Resolution Protocol (ARP) [2] datagrams for transmission across ARCNET [3] using the "ARCNET Packet Header Definition Standard" [4]. This memo offers a replacement for RFC 1051. RFC 1051 uses an ARCNET framing protocol which limits unfragmented IP packets to 508 octets [5].

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 19% of the total text.

Network Working Group D. Provan

Request for Comments: 1201 Novell, Inc.

Obsoletes: RFC 1051 February 1991

Transmitting IP Traffic over ARCNET Networks

Status of this Memo

This memo defines a protocol for the transmission of IP and ARP

packets over the ARCnet Local Area Network. This RFC specifies an

IAB standards track protocol for the Internet community, and requests

discussion and suggestions for improvements. Please refer to the

current edition of the "IAB Official Protocol Standards" for the

standardization state and status of this protocol. Distribution of

this memo is unlimited.

1. Introduction

This memo specifies a method of encapsulating Internet Protocol (IP)

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

transmission across ARCNET [3] using the "ARCNET Packet Header

Definition Standard" [4]. This memo offers a replacement for RFC

1051. RFC 1051 uses an ARCNET framing protocol which limits

unfragmented IP packets to 508 octets [5].

2. ARCNET Packet Format

In 1989, Apple Computers, Novell, ACTINET Systems, Standard

Microsystems, and Pure Data Research agreed to use the ARCNET

datalink protocol defined in "ARCNET Packet Header Definition

Standard" [4]. We'll begin with a brief description of that

protocol.

2.1. ARCNET Framing

ARCNET hardware supports two types of frames: short frames, which are

always 256 octets long, and long frames, which are always 512 octets

long. All frames begin with a hardware header and end with the

client's data preceded by a software header. Software places padding

in the middle of the packet between the hardware header and the

software header to make the frame the appropriate fixed length.

Unbeknown to the software, the hardware removes this padding during

transmission.

Short frames can hold from 0 to 249 octets of client data. Long

frames can hold from 253 to 504 octets of client data. To handle

frames with 250, 251, or 252 octets of data, the datalink protocol

introduces a third frame type: the exception frame.

These three frame formats are shown here. Except as noted, each

block represents one octet.

Short Frame Long Frame Exception Frame

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

| source | | source | | source |

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

| destination | | destination | | destination |

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

| offset | | 0 | | 0 |

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

. unused . | offset | | offset |

. (offset - 3 . +---------------+ +---------------+

. octets) . . unused . ...