System information

Troubleshooting ISDN Connections 17-377
Troubleshooting ISDN
Figure 17-4 ISDN Circuit-Switched Call Stages
Troubleshooting ISDN
This section presents troubleshooting information for ISDN connectivity and performance
problems. It describes specific ISDN symptoms, the problems that are likely to cause each symptom,
and the solutions to those problems.
The following sections describe the most common network issues when working with ISDN:
• ISDN: Router Does Not Dial
• ISDN: Dial Does Not Go Through BRI
• ISDN: Dial Does Not Go Through PRI
• ISDN: No Communication with Remote Router
• ISDN: No Communication End-to-End
• ISDN: Second B Channel Does Not Come Up
Alerting
Connect
Information
Pick up
Flow
Router
call
Calling
DTE
Calling
DCE
Called
DCE
Called
DTE
Called
router
Pick up
Information
Set up
Information
Release complete
Release complete
Flow
Connect ACK
Ringing
Flow
Set up
Information
Hang up
Disconnect
Disconnect
Set up ACK
Call proceeding
Release Release
Ring back indication
Stop ring back indication
Information
Alerting
Connect
Flow