Sip Trunk Intermittent

[Seski Ramadhan]

Hi All,

We're just having issue with SIP trunk, when we try to do DOD via PSTN, and when call connected, sometime voice is silent for 1 or 2 seconds, caller from internal always hear what external talk, but external sometimes can't hear voice from internal for 1 or 2 second,

Hope you guys give me recommendations such as what debug should I do, or another thing to get better log

[Hari Prasad]

Hello Seski,

Is the call flow like below.

Phone >> SIP>> CUCM>>SIP>>Gateway>>ITSP SIP provider >>PSTN number

or

Phone >> SIP>> CUCM>>SIP>>Gateway>>E1 PRI >>PSTN number

If the call flow involved ITSP provider then you will have to take packet capture from Phone and Gateway.

If the call flow involved E1 Controller , you need to verify if there is any issue with Controller like slip sec and crc error,  then you will have to take packet capture from phone , gateway sip leg and PCM capture for the ISDN leg.

[Seski Ramadhan]

Hi Hari Prasad,

Thx for replying, topology is this one

Phone >> SIP>> CUCM>>SIP>>Gateway>>ITSP SIP provider >>PSTN number

What do you mean by capture packet, do you mean with wireshark? do we need do some debug etc?

Thx a lot

[Hari Prasad]

Hello Seski,

With debugs you can trace the call only.

To troubleshoot the one way audio or voice quality issue , packet capture is the best option.

Please follow below URL to take capture

1- Packet capture from Phone

https://community.cisco.com/t5/collaboration-voice-and-video/collecting-a-packet-capture-from-a-cisco-ip-phone/ta-p/3119480
https://www.uccollabing.com/how-to-collect-packet-capture-from-cisco-ip-phone/

2- Packet capture from Gateway-

https://www.cisco.com/c/en/us/support/docs/voice/h323/116078-technologies-technote-commandrefe.html

Once you done with packet capture , open the pcap file using wireshark to check the issue or attachd pacp file here to check the issue.