1.. SPDX-License-Identifier: GPL-2.0
2
3==================
4Linux X.25 Project
5==================
6
7As my third year dissertation at University I have taken it upon myself to
8write an X.25 implementation for Linux. My aim is to provide a complete X.25
9Packet Layer and a LAPB module to allow for "normal" X.25 to be run using
10Linux. There are two sorts of X.25 cards available, intelligent ones that
11implement LAPB on the card itself, and unintelligent ones that simply do
12framing, bit-stuffing and checksumming. These both need to be handled by the
13system.
14
15I therefore decided to write the implementation such that as far as the
16Packet Layer is concerned, the link layer was being performed by a lower
17layer of the Linux kernel and therefore it did not concern itself with
18implementation of LAPB. Therefore the LAPB modules would be called by
19unintelligent X.25 card drivers and not by intelligent ones, this would
20provide a uniform device driver interface, and simplify configuration.
21
22To confuse matters a little, an 802.2 LLC implementation is also possible
23which could allow X.25 to be run over an Ethernet (or Token Ring) and
24conform with the JNT "Pink Book", this would have a different interface to
25the Packet Layer but there would be no confusion since the class of device
26being served by the LLC would be completely separate from LAPB.
27
28Just when you thought that it could not become more confusing, another
29option appeared, XOT. This allows X.25 Packet Layer frames to operate over
30the Internet using TCP/IP as a reliable link layer. RFC1613 specifies the
31format and behaviour of the protocol. If time permits this option will also
32be actively considered.
33
34A linux-x25 mailing list has been created at vger.kernel.org to support the
35development and use of Linux X.25. It is early days yet, but interested
36parties are welcome to subscribe to it. Just send a message to
37majordomo@vger.kernel.org with the following in the message body:
38
39subscribe linux-x25
40end
41
42The contents of the Subject line are ignored.
43
44Jonathan
45
46g4klx@g4klx.demon.co.uk
47