Wow Frank, that is a lot of troubleshooting, and a great run down. Can I ask what your failure rate is?
We have about a 2-4% failure rate and have decided not to troubleshoot those as they tend to be a Telco issue between us and the sender. We use a lot of toll bypass so if it doesn't work over a pri then we send it out another one. Usually fixes most of our problems ;-) Scott On Wed, Apr 5, 2017 at 5:06 PM, Frank Arrasmith <frank.arrasm...@gmail.com> wrote: > Calling all Rightfax gurus, > I have the following question regarding the Rightfax configuration and > transmission errors. > > Background: > My enterprise has CUCM 10.5 with a pretty dialed in Fax/T38 setup over SIP > and MGCP gateways. For the most part, faxing is pretty solid inbound and > outbound to and from PSTN GW's, CUBEs, ,analog VG's, and regular fax > machines(we have a lot). We have a SIP trunk connected to Rightfax 10.5 > server, which is managed by another group where we have limited > access/experience with Rightfax configuration settings. It took us awhile > to get the Rightfax servers with the correct t38 setup because they had > only run traditional CAS T1 prior to us, so it was new to everyone, but it > is up and stable except for the following issue.. > > Symptom : > The problem we see with Rightfax is with Transmission errors. It starts > with our internal customers reporting that they do not receive a fax even > when the sender receives confirmation. Upon further review we see that the > suspect call is listed as a "Transmission Error" in Rightfax, so the fax > never gets delivered to the customers account/mailbox even though the call > completes. > > Analysis: > Since we are running T38, we can packet capture at the server, and we see > normal fax protocol exchange, except for the suspect calls where we see > "RTN" Messages. My understanding of the T.30 protocol is that when a RTN > message is delivered to the sender, that is an indication for the sender to > slow down and resend the last page. We actually see in the messages where > the RTN message gets sent, and the sender complies with the notice, and > sends again at 12000, then call completes as normal with an EOP message and > a DCN message. In these cases,the Rightfax team actually looks at the fax > image and may see a bit of blurriness, but perfectly legible text ,even tho > its still marked as transmission failure. We have asked them if there is a > setting that can be tuned where the RTN does not cause the service to mark > the transmission as failure. To this they reply, "It was working fine > before when we were on CAS, so it must be on your end." > > I understand where there are cases where the RTN message is sent because > the call quality is actually terrible, but in those cases, there is usually > several RTN messages and the sender will drop down to 4800 or below , and > then usually give up and the call will fail. This type of failure is rare > (unless we have a major outage) and in this case the sending fax sees that > it failed and will proceed with its normal retries. > > Question: > > Is this RTN to transmission failure hard coded, or is this a configurable > setting? If this were a regular fax machine, i think this would be a non > issue as the receiver would see the crappy page as well as the good copy of > that was sent again in their bundle of received pages. > > Any insight is greatly appreciated and for anyone just getting into FAX > over IP with Cisco, I highly recommend the following book and Cisco Live > presentations from these guys from Cisco TAC. > > Fax, Modem, and Text for IP Telephony [Book] > <https://www.google.com/aclk?sa=l&ai=DChcSEwiXgOn0wY7TAhXJCioKHRVCANoYABAMGgJ0bQ&sig=AOD64_1ddnEIE3WNy8NH5g7yJ-WnrcChJA&ctype=5&q=&ved=0ahUKEwjei-P0wY7TAhUnj1QKHejtCy0QwzwIEg&adurl=> > from Textbooks.com > by David Hanes, Gonzalo Salgueiro > > > > > > > Thanks, > Frank > > > > _______________________________________________ > cisco-voip mailing list > cisco-voip@puck.nether.net > https://puck.nether.net/mailman/listinfo/cisco-voip > >
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