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diff --git a/Documentation/isdn/README.x25 b/Documentation/isdn/README.x25 deleted file mode 100644 index e561a77c4e22..000000000000 --- a/Documentation/isdn/README.x25 +++ /dev/null @@ -1,184 +0,0 @@ - -X.25 support within isdn4linux -============================== - -This is alpha/beta test code. Use it completely at your own risk. -As new versions appear, the stuff described here might suddenly change -or become invalid without notice. - -Keep in mind: - -You are using several new parts of the 2.2.x kernel series which -have not been tested in a large scale. Therefore, you might encounter -more bugs as usual. - -- If you connect to an X.25 neighbour not operated by yourself, ASK the - other side first. Be prepared that bugs in the protocol implementation - might result in problems. - -- This implementation has never wiped out my whole hard disk yet. But as - this is experimental code, don't blame me if that happened to you. - Backing up important data will never harm. - -- Monitor your isdn connections while using this software. This should - prevent you from undesired phone bills in case of driver problems. - - - - -How to configure the kernel -=========================== - -The ITU-T (former CCITT) X.25 network protocol layer has been implemented -in the Linux source tree since version 2.1.16. The isdn subsystem might be -useful to run X.25 on top of ISDN. If you want to try it, select - - "CCITT X.25 Packet Layer" - -from the networking options as well as - - "ISDN Support" and "X.25 PLP on Top of ISDN" - -from the ISDN subsystem options when you configure your kernel for -compilation. You currently also need to enable -"Prompt for development and/or incomplete code/drivers" from the -"Code maturity level options" menu. For the x25trace utility to work -you also need to enable "Packet socket". - -For local testing it is also recommended to enable the isdnloop driver -from the isdn subsystem's configuration menu. - -For testing, it is recommended that all isdn drivers and the X.25 PLP -protocol are compiled as loadable modules. Like this, you can recover -from certain errors by simply unloading and reloading the modules. - - - -What's it for? How to use it? -============================= - -X.25 on top of isdn might be useful with two different scenarios: - -- You might want to access a public X.25 data network from your Linux box. - You can use i4l if you were physically connected to the X.25 switch - by an ISDN B-channel (leased line as well as dial up connection should - work). - - This corresponds to ITU-T recommendation X.31 Case A (circuit-mode - access to PSPDN [packet switched public data network]). - - NOTE: X.31 also covers a Case B (access to PSPDN via virtual - circuit / packet mode service). The latter mode (which in theory - also allows using the D-channel) is not supported by isdn4linux. - It should however be possible to establish such packet mode connections - with certain active isdn cards provided that the firmware supports X.31 - and the driver exports this functionality to the user. Currently, - the AVM B1 driver is the only driver which does so. (It should be - possible to access D-channel X.31 with active AVM cards using the - CAPI interface of the AVM-B1 driver). - -- Or you might want to operate certain ISDN teleservices on your linux - box. A lot of those teleservices run on top of the ISO-8208 - (DTE-DTE mode) network layer protocol. ISO-8208 is essentially the - same as ITU-T X.25. - - Popular candidates of such teleservices are EUROfile transfer or any - teleservice applying ITU-T recommendation T.90. - -To use the X.25 protocol on top of isdn, just create an isdn network -interface as usual, configure your own and/or peer's ISDN numbers, -and choose x25iface encapsulation by - - isdnctrl encap <iface-name> x25iface. - -Once encap is set like this, the device can be used by the X.25 packet layer. - -All the stuff needed for X.25 is implemented inside the isdn link -level (mainly isdn_net.c and some new source files). Thus, it should -work with every existing HL driver. I was able to successfully open X.25 -connections on top of the isdnloop driver and the hisax driver. -"x25iface"-encapsulation bypasses demand dialing. Dialing will be -initiated when the upper (X.25 packet) layer requests the lapb datalink to -be established. But hangup timeout is still active. Whenever a hangup -occurs, all existing X.25 connections on that link will be cleared -It is recommended to use sufficiently large hangup-timeouts for the -isdn interfaces. - - -In order to set up a conforming protocol stack you also need to -specify the proper l2_prot parameter: - -To operate in ISO-8208 X.25 DTE-DTE mode, use - - isdnctrl l2_prot <iface-name> x75i - -To access an X.25 network switch via isdn (your linux box is the DTE), use - - isdnctrl l2_prot <iface-name> x25dte - -To mimic an X.25 network switch (DCE side of the connection), use - - isdnctrl l2_prot <iface-name> x25dce - -However, x25dte or x25dce is currently not supported by any real HL -level driver. The main difference between x75i and x25dte/dce is that -x25d[tc]e uses fixed lap_b addresses. With x75i, the side which -initiates the isdn connection uses the DTE's lap_b address while the -called side used the DCE's lap_b address. Thus, l2_prot x75i might -probably work if you access a public X.25 network as long as the -corresponding isdn connection is set up by you. At least one test -was successful to connect via isdn4linux to an X.25 switch using this -trick. At the switch side, a terminal adapter X.21 was used to connect -it to the isdn. - - -How to set up a test installation? -================================== - -To test X.25 on top of isdn, you need to get - -- a recent version of the "isdnctrl" program that supports setting the new - X.25 specific parameters. - -- the x25-utils-2.X package from - ftp://ftp.hes.iki.fi/pub/ham/linux/ax25/x25utils-* - (don't confuse the x25-utils with the ax25-utils) - -- an application program that uses linux PF_X25 sockets (some are - contained in the x25-util package). - -Before compiling the user level utilities make sure that the compiler/ -preprocessor will fetch the proper kernel header files of this kernel -source tree. Either make /usr/include/linux a symbolic link pointing to -this kernel's include/linux directory or set the appropriate compiler flags. - -When all drivers and interfaces are loaded and configured you need to -ifconfig the network interfaces up and add X.25-routes to them. Use -the usual ifconfig tool. - -ifconfig <iface-name> up - -But a special x25route tool (distributed with the x25-util package) -is needed to set up X.25 routes. I.e. - -x25route add 01 <iface-name> - -will cause all x.25 connections to the destination X.25-address -"01" to be routed to your created isdn network interface. - -There are currently no real X.25 applications available. However, for -tests, the x25-utils package contains a modified version of telnet -and telnetd that uses X.25 sockets instead of tcp/ip sockets. You can -use those for your first tests. Furthermore, you might check -ftp://ftp.hamburg.pop.de/pub/LOCAL/linux/i4l-eft/ which contains some -alpha-test implementation ("eftp4linux") of the EUROfile transfer -protocol. - -The scripts distributed with the eftp4linux test releases might also -provide useful examples for setting up X.25 on top of isdn. - -The x25-utility package also contains an x25trace tool that can be -used to monitor X.25 packets received by the network interfaces. -The /proc/net/x25* files also contain useful information. - -- Henner |