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Standard for the transmission of IP datagrams over experimental Ethernet networks (RFC0895)

IP.com Disclosure Number: IPCOM000003944D
Original Publication Date: 1984-Apr-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 3 page(s) / 5K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J. Postel: AUTHOR

Abstract

This memo applies to the Experimental Ethernet (3-megabit/second, 8-bit addresses). The procedure for transmission of IP datagrams on the Ethernet (10-megabit/second, 48-bit addresses) is described in [3].

This text was extracted from a ASCII Text document.
This is the abbreviated version, containing approximately 63% of the total text.

Network Working Group Jon Postel

Request for Comments: 895 ISI

April 1984

A Standard for the Transmission of IP Datagrams

over Experimental Ethernet Networks

Status of this Memo

This RFC specifies a standard method of encapsulating Internet

Protocol (IP) [1] datagrams on an Experimental Ethernet [2]. This

RFC specifies a standard protocol for the ARPA Internet community.

Introduction

This memo applies to the Experimental Ethernet (3-megabit/second,

8-bit addresses). The procedure for transmission of IP datagrams on

the Ethernet (10-megabit/second, 48-bit addresses) is described in

[3].

Frame Format

IP datagrams are transmitted in standard Experimental Ethernet

frames. The type field of the Ethernet frame must contain the value

513 (1001 octal). The data field contains the IP header followed

immediately by the IP data.

If necessary, the data field should be padded to meet the

Experimental Ethernet minimum frame size. This padding is not part

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

IP header.

The maximum length of an IP datagram sent over an Experimental

Ethernet is 1536 octets. Implementations are encouraged to support

full-length packets. Gateway implementations MUST be prepared to

accept full-length packets and fragment them if necessary. If a

system cannot receive full-length packets, it should take steps to

discourage others from sending them, such as using the TCP Maximum

Segment Size option [4].

Note: Datagrams on the Ethernet may be longer than the general

Internet default maximum packet size of 576 octets. Hosts connected

to an Ethernet should keep this in mind when sending datagrams to

hosts not on the same Ethernet. It may be appropriate to send

smaller datagrams to avoid unnecessary fragmentation at intermediate

gateways. Please see [4] for further information on this point.

RFC 895 April 1984

Address Mappings

The mapping between 32-bit Internet addresses to 8-bit Experimental

Ethernet addresses can be done several ways.

The easiest thing to do is to use the last eight bits of host number

part of the Internet address as the host's address on the

Experimental Ethernet. This is the recommended approach.

Broadcast Address

The broadcast Internet address (the address on that network with a

host part of all binary ones) should be mapped to the broadcast

Experimental Ethernet address (address zero).

Trailer Formats

Some versions of Unix 4.2bsd use a different encapsulation method in

order to get better network performance with the VAX virtual memory

architecture. Consenting systems on the same Ethernet may use this

format between themselves.

No host is required to implement it, and no datagrams...