I have 1000s of locations running isdn as backup with C-DOT Exchange.
Im facing problem often with these SVCs that call will get disconnected with in 20 secs.- Normal call clearing
I have solved this issue by getting a switch port reset at exchange(provider) or by changing the port at exchange(Provider).
Some how i reached to a conclusion that this is a provider issue.
Have anyone faced this issue (Especialy in india - BSNL).
Is there any workaround / solution by tuning timers or changing some configuration in router?