This document discusses how to Troubleshoot No-way audio/ dead Air Issue for the PSTN Outbound and Inbound Calls.
Outbound and inbound calls are not working - no-way audio. The PSTN Outbound and Inbound Calls are going through and getting connected fine but after that there is nothing heard, No-way audio/dead air issue for the PSTN calls outbound.
Mobile phone->PSTN -T1 PRI--> MGCP Gateway -->CUCM -- IP Phone
MGCP Gateway IOS version 12.1
1) The CUCM traces revealed that the call was connected fine and there was no issue found in the sdi/sdl traces.
CUCM only plays role in the call setup /tear-down of connection but not during conversation.
The Inbound and outbound calls have symptoms of dead air.
CUCM traces reveal that the call connects all fine and there seems to be loss of audio packets.
While testing the call customer didn't notice any change in TX count. It was showing zero while RX count was increasing gradually.
Installed the Wireshark tool.
2) The Gateway isdn debugs below also didn't reveal the root cause. MGCP Gateway Debugs
MGCP Gateway Debug for Troubleshooting
Transfer Capability = Speech
Transfer Mode = Circuit
Transfer Rate = 64 kbit/s
Channel ID i = 0xA98381
Exclusive, Channel 1
Facility i = 0x9F8B0100A10F02014A06072A8648CE1500040A0100