ISDN problems

[battanc]

I have a scenary like this: site A (main site) with 2503 + 2610, site B with 2503, site C with 2610, site D with 2610.

A is connected directly with B, C and D over 3 lines CDN-64k, plus ISDN as Back-Up for each; no direct connection between B, C and D.

It is happend 3 times that one router continuously for 3-4 weeks placed an ISDN call ever 10-11 seconds, also with the CDN (main line) UP. This happend random: A/1 to C, B to A/1 and D to A/2, causing a very HIGH cost to the TeleCom (over 60,000 calls every accident !).

It is no log of the events: the problem stars and ends with no apparent reason and disappear without any modification in the configuration; it is noted only after some time, by the invoice of the TeleCom ...

I hope, it can be a bug in the IOS: 2503 with 11.2 (A/1 with 11.2.5p and B with 11.2.11), 2610 with 11.3.

Any other idea?

[makchitale]

Since we have dial on demand routing (DDR) here, there has to be some interesting traffic to trigger a call. How are you enabling backup...by using the backup interface command / floating static routes or dialer watch?

Ideally will need to see the running configs on the routers & when the problem happens "debug dialer" will be helpful / sh ip route will indicate whether the calling router is dialing since it's lost the route to the other end.

If you have enough memory onboard atleast move up to 11.3 on all routers.

Thanks, Mak.