[c-nsp] ISDN Callback problem

[Sascha E. Pollok]

Folks,

I am currently debugging an ISDN callback-problem. We are calling
a customer's router which is supposed to reject the call on the
ISDN layer (q931) and then callback so that the $$$'s end up on
the customer's invoice.

Everytime I test this, it is working fine. I turn on debugging for
the dialer, I see the callback. It is not picking up the line.

But: last week I had to explain LOTS(!) of dialout-connections on
one of our phone bills and had some trouble finding a good reason
for this. For whatever reason the router seems to be picking up
the line sometimes leaving it open for 30-50 seconds.

Unfortunately there is no syslog server on the customer's side in order
to turn on some debugging switches and everytime i use logging buffered
it's not happening or it's overwritten ...

Below is the configuration of the customer's router. They have two
lines connected. The number we dial out to the router is the one
connected to one of the BRIs.

Anyone?

This is 12.3(1a) on a 1751.

interface BRI0/0
 no ip address
 no ip redirects
 encapsulation ppp
 load-interval 30
 dialer pool-member 1
 isdn switch-type basic-net3
 isdn caller 004940xxxxxxxxxx callback
 ppp multilink
!
interface BRI1/0
 no ip address
 no ip redirects
 encapsulation ppp
 load-interval 30
 dialer pool-member 1
 isdn switch-type basic-net3
 isdn caller 004940xxxxxxxxxx callback
 ppp multilink
!
interface Dialer1
 description To NAS
 ip unnumbered FastEthernet0/0
 encapsulation ppp
 no ip route-cache
 dialer pool 1
 dialer idle-timeout 180
 dialer enable-timeout 20
 dialer string 004940xxxxxxxxxx
 dialer caller 004940xxxxxxxxxx callback
 dialer load-threshold 50 either
 dialer-group 1
 ppp authentication chap callin
 ppp chap hostname xxxxxxxxx
 ppp chap password 7 yyyyyyyyyyyy
 ppp multilink


Thanks + cheers
Sascha