Inbound Large Fax Disconnects In Middle of Fax

[melinda.clancy]

I have Callmanager 7.1.5.10000-12 with H323 gateways, gatekeepers for ICM/CVP routing, and PRI's for PSTN.  We are in the process of removing physical fax machines and placing them on a FaxCom application.  We also have an old FaxCom that the connection between Callmanager and the FaxCom are analog lines.  This new FaxCom has a SIP trunk between Callmanager and the new FaxCom.

My issue is inbound large faxes.  Several of our departments receive faxes that can be 100 pages.  There is not any issues with our physical fax machines or the old Faxcom receiving these large faxes.  But of course, the new FaxCom, when we go to receive a large fax will timeout and disconnect.  Only half of the pages get received.  We do not have any issues sending these large faxes from the new FaxCom, only receiving.  Small faxes do not have this issue, only the large ones.

I thought maybe it was a PSTN or gateway issue, so I tested with a different group of PRI's, different gateway, but still the same carrier.  I had the same issue.  I have done a Q921 and Q931.  Here is the output:

*Jul 24 13:36:41.244: %ISDN-6-DISCONNECT: Interface Serial0/1/0:1  disconnected from 8048974083 , call lasted 934 seconds
*Jul 24 18:36:41.244: ISDN Se0/1/0:23 Q921: User TX -> INFO sapi=0 tei=0, ns=79 nr=113
*Jul 24 18:36:41.244: ISDN Se0/1/0:23 Q931: DISCONNECT pd = 8  callref = 0x8255
        Cause i = 0x80A9 - Temporary failure
*Jul 24 18:36:41.252: ISDN Se0/1/0:23 Q921: User RX <- RR sapi=0 tei=0 nr=80
*Jul 24 18:36:41.956: ISDN Se0/1/0:23 Q921: User RX <- INFO sapi=0 tei=0, ns=113 nr=80
*Jul 24 18:36:41.956: ISDN Se0/1/0:23 Q931: RELEASE pd = 8  callref = 0x0255
*Jul 24 18:36:41.956: ISDN Se0/1/0:23 Q921: User TX -> RR sapi=0 tei=0 nr=114
*Jul 24 18:36:41.956: ISDN Se0/1/0:23 Q921: User TX -> INFO sapi=0 tei=0, ns=80 nr=114
*Jul 24 18:36:41.956: ISDN Se0/1/0:23 Q931: RELEASE_COMP pd = 8  callref = 0x8255
*Jul 24 18:36:41.964: ISDN Se0/1/0:23 Q921: User RX <- RR sapi=0 tei=0 nr=81

Do you have any ideas for what might be wrong?  The new FaxCom folks say it is a PSTN issue.  I am not sure I agree.

Your help would be greatly appreciated.

Thanks Melinda
 

[George Thomas · Accepted solution]

Jul 24 18:36:41.244: ISDN Se0/1/0:23 Q931: DISCONNECT pd = 8  callref = 0x8255

The 0x8 means that the message is from the provider which means the provider is disconnecting the call.

[melinda.clancy]

Thanks, sounds strange, only because they are not disconnecting on the outbound.  I am glad it is not my configuration.  This will be a fun call to the carrier.

Thank you very much.

I will update this when I have a resolution from the carrier on what they did to fix the issue.

[melinda.clancy]

With more testing, we found that the internal SIP trunk (CUCM) is the provider disconnecting the call.  With traces, we found, the Faxcom server is not responding to the SIP session refresh invites.  Since it is not responding, CUCM is disconnecting the call/fax.