ISDN call does not disconnect

[Eddthewire]

I have a router which is connected by ISDN, but after the branch finishes, the call does not disconnect.
This is now working out more expensive than the kilostream I took out.
Any help please

 

[MaxPipeline]

Look for some sort of idle timer to drop the call if no traffic is present. If you have already set the idle timer then you may have unwanted traffic keeping your connection active. What ISDN device do you have?

 

[Eddthewire]

I have set the idle timeout to 600 secs. The device I am using is a Cisco 1603 at both ends
Can I find out what data may be keeping the line up ?

 

[MaxPipeline]

I do not know if the Cisco 1603 router has any WAN tracing capabilities. In the meantime you can try lowering your idle timeout to a lower number as 600 seconds is alot of time in which any number of things can be destined for hte WAN. Maybe 60 seconds for testing puposes. Also you can try a network sniffer to determine what traffic may be destined out through the WAN. Once you isolate what may be causing it you can then look into either fixing the problem or blocking it using firewall/filters.

 

[BAsh12]

You can find out exactly what is causing this easy.


Telnet into the cisco router, and get into enable mode.

Once in, type "term mon" that will then allow the router to send console messages to you. I think you can also type "logging synchronous" and it will interrupt the sesion when you type.

Once you have done this, go the the bri interface. The command will be something like this.

conf t
int bri0
shut.
ctrl z

The shut command will close down the interface.

Then, type the following

debug isdn events
debug dialer (if you are using dialers and not legacy)

The next step is to capture the screen. In hyperterm go to "transfer" and "capture text"

Then the reverse of the shut

conf t
int bri0
no shut

What ever is bringing the line up will show on screen.

The best time to do this is after hours, there will be many devices I suspect that during working hours will bring the link up. You want to find the one in the evening that is doing it.

If you think you missed it, you can keep shutting and opening the bri as before.

Don't forget that debug is cpu intensive, when you have finished, type

no debug all

And debugging will finish. Also, do not forget to stop the capture.

You can play with this quite a bit. Have a look at

debug isdn q931.

That will debug layer 3

and
debug isdn q921

You can see the d channel then.

Hope this helps.

 

[m40chm]

Is your router running RIP? Use "show ip protocol" to see.

If you do a "show isdn hist" and keep refreshing the command using the up key/enter combo, do you see the idle timer get to around 26 to 30 seconds then reset? This is a sure sign that rip routing updates are keeping your BRIs active.

If so, in config mode enter "no router rip", come out of config and use the "show isdn hist" again a before. If the counter goes abaove 31 seconds, you win

Steve.