LZS for ISDN for Linux

In 1998, I wrote a CCP backend module for the I4L ISDN implementation that is somewhat compatible to LZS (RFC1974) compression, better known as Stac. The solution is still in a BETA state, but has been used by a number of people over the last years. Now that german mass dialin provider T-Online started to officially support compression, and that compression beeing LZS EXT mode, interest into the code bumped up suddenly.

A complete kernel patch

I used to just publish the source I've written, but getting it into the kernel was a task left to the user. This might not be much of a fuzz to a kernel developer, but for the occasional user it is a bit hard. Thanks to Frank Elsner there is a complete kernel patch available for some 2.2 and all 2.4 versions that can easily be applied by anyone able to patch and compile the kernel.

The files

The individual files that are automatically installed at the right place in the kernel source tree by the abovementioned patch are:


README.LZS		The obvious README
ChangeLog		Version change log
isdn_lzscomp.c		The latest compression module source (includes multi history, builds on 2.6)
isdn_lzscomp.c.1.21	Old 2.4 version (for reference only)
isdn_ppp.diff		Experimental patch to 2.2.19 (fixes MP)
    

Old stuff

Stuff that used to age around here has been moved to a subdirectory. It is an older version of the module as well as updates to code that should be in ipppd for years now. Traverse only for nostalgia.

License

The code is Copyleft 1998-2001 by Andre Beck under terms of the GNU GPL. While the code is provided free and under GPL, it may infringe patents Stac has applied for in the US and maybe other countries. Verify that this is not the case in your country before using it. This code is a private development related in no way whatsoever to my employer, written in Germany where software patents are still considered bogus. This situation might change any day due to EU law. Linux distributors who supply this stuff shrink wrapped should reconsider doing this (not only for isdn_lzscomp, but as well for isdn_bsdcomp, which is likely to infringe on the infamous Unisys LZW patent) with their law departement.

For more information see http://www.delphion.com/


Andre Beck
Last modified: Thu Oct 4 13:53:36 MET DST 2001