Free Software Projects

ip_resend - Speed up demand-dial ppp links.

ip_resend aims at solving the problem of timeout related delays on demand-dial ppp links. Users frequently suffer from this if the ppp link uses dynamic IP-address assignment. These problems are, e.g., caused by the loss of the first DNS-lookup packet which triggered the demand-dialling.

ip_resend is implemented entirely in user space (no kernel patches required!). It should work with any Linux 2.2.x and 2.4.x kernel. It should work with isdn_ppp as well as async ppp.

eftp4linux - An implementation of the EUROFile Transfer Protocol for Linux

The EUROFile protocol is a file transfer protocol frequently used via the ISDN. More info about the Linux-implementation HERE.

linux-x25 - Software related to the Linux X.25 protocol implementation.

I am the current maintainer of the Linux X.25 protocol stack. If you use or want to use the protocol stack, have a look here.

In particular, there is a kind of mini FAQ. Patches to allow linux-x25 being used with the local loopback network interface are in loopback

There is currently work in progress to allow IP and PPP tunneling on top of linux-x25. Please have a look at the sk_tunnel directory. For an overview, please have a look at the extended abstract of a talk given at the Linux Kongress 2000. You can also download tarballs containing LaTeX source and PostScript files of the extended abstract and the slides.

GSM mobile phone <-> isdn4linux interconnection

I recently tried to connect two Linux machines via GSM and ISDN: The mobile computer was an Apple iBook (running Linux), which was attached to a Motorola Timeport 260 mobile GSM phone via an ATEN USB-serial adapter. The (ordinary) stationary (Linux) PC was attached to the ISDN via isdn4linux. This turned out to involve several non-trivial subtasks. The related experience is shared in this article. The effort resulted in two kernel patches:

Prolific PL2303 Driver

The driver for the ATEN UC232-A USB-serial-converter as present in Linux 2.4.9 did not work for me. The following patch adds missing features and increases reliability of the driver such that it finally fulfilled the requirements of the above project. patch is against kernel 2.4.9 and below, for 2.4.10 usethis

isdn4linux V.110 improvements

It turned out that the V.110 protocol implementation as present in the 2.4.9 kernel's isdn4linux stack could not fully exploit the bandwidth which a GSM data channel provides. Only 8/11 of the 9600 bps user data rate is accessible from current isdn4linux. The following patch remedies this. First, it adds support for V.110 flow control to isdn4linux (V.110 suports emulating serial line style RTS/CTS hardware flow control, but current isdn4linux did not implement this). And beside this, it adds support for two other V.110 baud rates (12000 bps and 14400 bps).

Background information and rationale about the patches is also contained in the above mentioned article:

Have a lot of fun


(c) Henner Eisen, Ziegeleistrasse 17, 22113 Oststeinbek, GERMANY,

eis (-: :-)