ISDN

The following is a list of ISDN internal modems known to work with SmoothWall GPL 1.0:
Eicon Diva Internal PCI
AsusCom TA-200 PCI

Most ISPs provide an ISDN service with free dialup - ie no cost for the actual dialup, but charge only per minute of connect time, or have a "permanent" connection option. A few also charge for the dialup - one particular Australian ISDN provider does this - you could call this "unidirectional financial osmosis". In the first case - no dialup charges - the default configuration of SmoothWall GPL will pose no problem - when bandwidth usage reaches 5000 bytes per second, the second channel will connect, then drop once bandwidth drops to below 5000 bytes per second for a period of 30 seconds.


For those users who have to pay for each dialup, this could be quite costly. SmoothWall GPL uses the "ISDN Bandwidth On Demand daemon" (ibod) to control the second (and subsequent) B-channel's status. What is needed is for this status to be configured to keep the second channel open permanently. To achieve this, you will need to edit the /etc/ppp/ibod.cf file and add the following two lines at the end of this file:-
STAYUP 1 # Keep all channels up once they have connected
STAYUP_TIME 0 # Never close it down


Although the STAYUP_TIME line is not strictly necessary, a bit of redundancy doesn't hurt here! :) These changes will cause the second line to stay up forever (until the hangup time is reached) once it has been brought up. The second channel will still only be brought up when the bandwidth across the link goes above 5000 bytes per second. There is another way around this issue, which is to disable ibod completely by editing /etc/ppp/ppp-on, removing the "ibod" reference and adding a section to bring the second line up automatically. Since this is more involved, and provides no real advantage, I'll not scare you with the details.


This page was last modified on 10 March, 2007.