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