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