I have a problem with VoIP over ISDN BRI connection in the following configuration:
Connection between routers and PBXs is made by ISDN BRI using VIC-2BRI-NT/TE in routers.
Ports BRI on routers are configured as NT (network side).
Routers are connected together with leased line (2Mb/s).
When phoneA initiates voice call to phoneB following is happened :
1. routerA transmits VoIP packets to routerB,
2. routerB transmits one SETUP frame (ITU Q.931) to PBXb; after 4 seconds next SETUP
3. PBXb is not responding
4. after few seconds routerA transmits DISCONNECT to PBXa with cause=0x80A2 No circuit/channel available
Transmitted numbers are correct. Layer1 and 2 - correct.
If anybody is interested - I have logs from debug isdn q931 and debug voice ccapi inout.
Thank you for any suggestions.