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Mustain
Beginner

SIP Incoming/Outgoing Fax Not Working

Hi Good People,

Please help me to solve my problem. I have a CUBE that works fine for Voice traffic, and now I'm configuring the T38 protocol to enable the fax service. The problem is FAX can only send/receive faxes if the others are running on SIP too. But if a different side is running on E1, the fax will not work.

I've gathered the debug output from CUBE, but still don't understand what's going on.

 

The call flow is: ITSP <--> SIP <--> CUBE <--> CUCM <--> MGCP <--> VG224 <--> FAX Machines.

 

Thanks in advance.

1 ACCEPTED SOLUTION

Accepted Solutions
Mustain
Beginner

The problem was solved. I tried to uncheck the MTP option on the CUCM SIP Trunk. And some things have been adjusted on the ITSP side such as Codecs, etc.

View solution in original post

10 REPLIES 10
BalajiSivaraj49175
Participant

SIP message may instruct that following threshold in the configuration

 

Capture21.JPG

Hi @BalajiSivaraj49175 

 

Thank you for your comment, would you like to provide an appropriate reference for your comment?

BalajiSivaraj49175
Participant

rules for message communication and sampling for channel information.

 

T.38 - Delay<1000ms, Jitter<300ms, Packet loss should be NONE unless T.38 with redundancy.
Passthrough - Delay<1000ms, Jitter<30ms, Packet loss should be NONE.
Protocol Based switchover - This is standard based.
NSE Based switchover - This is proprietary and works only between Cisco voice gateways.

BalajiSivaraj49175
Participant

Message communication between differant devices.Capture22.JPG

BalajiSivaraj49175
Participant

Can find the referance SIP communication message between the devices(FAX)

 

https://www.cisco.com/c/en/us/support/docs/voice/session-initiation-protocol-sip/118647-technote-sip-00.html

BalajiSivaraj49175
Participant

Debug message useful referaance to capture SIP message troubleshoot issue

 

Debug Capture.JPG

BalajiSivaraj49175
Participant

This are different messages communicate between the devises.

 

Capture23.JPG

BalajiSivaraj49175
Participant

GW and CUCM message communication frequency message communication when debug this infoCapture25.JPG

I've tried this, but it still doesn't solve my problem

Mustain
Beginner

The problem was solved. I tried to uncheck the MTP option on the CUCM SIP Trunk. And some things have been adjusted on the ITSP side such as Codecs, etc.

View solution in original post

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