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Nonstandard for transmission of IP datagrams over serial lines: SLIP (RFC1055)

IP.com Disclosure Number: IPCOM000001862D
Original Publication Date: 1988-Jun-01
Included in the Prior Art Database: 2000-Sep-12
Document File: 5 page(s) / 12K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

J.L. Romkey: AUTHOR

Abstract

The TCP/IP protocol family runs over a variety of network media: IEEE 802.3 (ethernet) and 802.5 (token ring) LAN's, X.25 lines, satellite links, and serial lines. There are standard encapsulations for IP packets defined for many of these networks, but there is no standard for serial lines. SLIP, Serial Line IP, is a currently a de facto standard, commonly used for point-to-point serial connections running TCP/IP. It is not an Internet standard. Distribution of this memo is unlimited.

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 23% of the total text.

Network Working Group J. Romkey

Request for Comments: 1055 June l988

A NONSTANDARD FOR TRANSMISSION OF IP DATAGRAMS OVER SERIAL LINES: SLIP

INTRODUCTION

The TCP/IP protocol family runs over a variety of network media:

IEEE 802.3 (ethernet) and 802.5 (token ring) LAN's, X.25 lines,

satellite links, and serial lines. There are standard encapsulations

for IP packets defined for many of these networks, but there is no

standard for serial lines. SLIP, Serial Line IP, is a currently a de

facto standard, commonly used for point-to-point serial connections

running TCP/IP. It is not an Internet standard. Distribution of

this memo is unlimited.

HISTORY

SLIP has its origins in the 3COM UNET TCP/IP implementation from the

early 1980's. It is merely a packet framing protocol: SLIP defines a

sequence of characters that frame IP packets on a serial line, and

nothing more. It provides no addressing, packet type identification,

error detection/correction or compression mechanisms. Because the

protocol does so little, though, it is usually very easy to

implement.

Around 1984, Rick Adams implemented SLIP for 4.2 Berkeley Unix and

Sun Microsystems workstations and released it to the world. It

quickly caught on as an easy reliable way to connect TCP/IP hosts and

routers with serial lines.

SLIP is commonly used on dedicated serial links and sometimes for

dialup purposes, and is usually used with line speeds between 1200bps

and 19.2Kbps. It is useful for allowing mixes of hosts and routers

to communicate with one another (host-host, host-router and router-

router are all common SLIP network configurations).

AVAILABILITY

SLIP is available for most Berkeley UNIX-based systems. It is

included in the standard 4.3BSD release from Berkeley. SLIP is

available for Ultrix, Sun UNIX and most other Berkeley-derived UNIX

systems. Some terminal concentrators and IBM PC implementations also

support it.

SLIP for Berkeley UNIX is available via anonymous FTP from

uunet.uu.net in pub/sl.shar.Z. Be sure to transfer the file in

binary mode and then run it through the UNIX uncompress program. Take

the resulting file and use it as a shell script for the UNIX /bin/sh

(for instance, /bin/sh sl.shar).

PROTOCOL

The SLIP protocol defines two special characters: END and ESC. END is

octal 300 (decimal 192) and ESC is octal 333 (decimal 219) not to be

confused with the ASCII ESCape character; for the purposes of this

discussion, ESC will indicate the SLIP ESC character. To send a

packet, a ...