Implementing and Operating Cisco Collaboration Core Technologies (CLCOR) — Question 456

An engineer is troubleshooting a Primary Rate Interface that fails to come up on a H.323 production voice gateway. Layer 1 and Layer 2 configurations were validated successfully. Which Cisco IOS command must be run to debug the issue with the least impact on network performance?

Answer options

• A. debug vtsp session
• B. debug ccsip messages
• C. debug all
• D. debug isdn q931

Correct answer: D

Explanation

The command 'debug isdn q931' is specifically designed to monitor Q.931 signaling messages, which are crucial for ISDN connections, making it ideal for troubleshooting this scenario with minimal impact. In contrast, 'debug all' would generate excessive output and potentially degrade performance, while 'debug ccsip messages' and 'debug vtsp session' are not directly related to ISDN troubleshooting.