17. leased: Leased lines

17.1 leased: How does establishing and ending a connection work with D64S without signaling?

The data are simply sent out! If you at the end of the D64S or 2MB line, you tell your router that the line itself is "up". You have - other than with ping etc. - NO possibility to recognize whether the connection is there or not. (with ISPA for example, the outgoing wheels turn...) The only thing that you can measure on your site is the loop to the next switching station. If you used Bchan2 instead of Bchan1 and send out data, they have to come back. Then you can take your statistics. The assumes that the Telekom has the unused Bchan setup this way at the switching station. This way we once proved to the Telekom the line itself had a broken cable... What can happen, if you don't automatically assume that the line is there, that no data will flow if the other side is not yet "up". With ISPA, for example, the pseudo numbers 1tap or 2tap are first called with the first data packets and the protocol is started. Incoming packets are simply ignored, among other reasons because of the missing signaling. Only S01 or S02 lines have a D channel and have something to use with signaling, however the best known solutions also use this 16kb for data transfers to get 144kb instead of 128kb. So just try it by sending out the data, assuming that line is there :-). In this case the data end up in Nirvana...

17.2 leased: With i4l, how can I successfully use the Teles card on a D64 leased line?

A later version of the new HiSax driver will support D64 (more about this driver above). Configuration is normal with the following specialities. HiSax has to be run in leased mode:

/sbin/telesctrl HiSax 5 0

# bind interface on first BChannel (,1 for 2nd)
/sbin/isdnctrl bind HiSax,0
/sbin/isdnctrl eaz isdn0 1
/sbin/isdnctrl addphone isdn0 out 2
/sbin/isdnctrl addphone isdn0 in  3

Marcus Graf marcus@www.weinheim.de has made available his experience as a short info on http://www.weinheim.de/isdn/index.html

17.3 leased: Can I connect two computers with ICN cards over a D64s leased line? How? Where can I find documentation?

Torsten Hentschel Torsten.Hentschel@DInet.de wrote on 2 Jan 1997:

That surely works. We have it working here. It's also stable (kernel 2.0.26 is necessary, otherwise the router might come to a halt). Only, if you pull out the plug to the terminal adapter and insert it again, or if the Telekom produces an error, then you have to have both sides hang up once (or twice) to bring the connection backup. In emergency you have a "ping" and a "isdnctrl hangup" done with cron. I don't know of any other docs or source code, but I'd be happy to help with any further questions, since other helped me before There are several things to watch out for. LEASEDx is the incoming number on the device; an outgoing number is not necessary, since the kernel (or the firmware, I'm not sure) generates pseudo-incoming calls, as long as no one has "picked up". In LEASED x, the small "x" should be replaced by the number of the SO interface. In each of our routers we have four interfaces (numbered as 0, 1, 2, 3), and I used the last interface as the LEASED line. That makes sense, since the other three interfaces are used for 6 B channels for dialup lines, and the kernel always uses the first free line for outgoing calls. If the leased line were on interface 0, then the second B channel of the leased line would appear (but only appear) to be free. The kernel doesn't notice (because of the active card) that there is no D channel for dialing there, and will dial, and dial, and dial. For this reason, I've created an extra ISDN network interface and have bound it exclusively to the apparent B channel of the leased line, so that after 6 dialout lines are in use the kernel attempt to dial out on the leased line. Another important stumbling block is that the first pseudo- incoming call must be answered (otherwise only the third, then the fifth will work, I don't know exactly why, but I suspect it's caused by the two B channels, for which calls are generated in turn, while a D64 has only one B channel). The immediate acceptance of the call is setup as follows: * Load the module for the ICN card and configure (load the firmware, bus reject, ...) BUT NOT YET icnctrl -d XXX leased" * Generate the network interface for the kernel with innumber LEASEDx and all the other stuff you need (IP address, ...). Don't forget to bind to the appropriate S0 interface. * NOW: icnctrl -d XXX leased The network interface has to already be up when "icnctrl -d XXX leased" is called. Then this command starts the first call and can then be immediately answered - and pop, the connection is made.

G. Richter richter@ecos.de added on 3 Jan 1997:

This has worked for use (with a CISCO router as partner) with no problems for nearly two months.

Make sure the EAZ is set to 1 and the the line is set to leased with isdnctrl, the rest is just like a dialup line (except telephone number and timeouts)

An example script is under http://www.rosat.mpe-garching.mpg.de/~web/ISDN.html

17.4 leased: With ISDN, can I use one channel as a leased line and other as a dialup line?

Tomas Pospisek tpo@spin.ch wrote:

Yes, you can (at least in Switzerland). You have to make sure you are on the correct channel ;)