Opening A Tac Case - Cisco BTS 10200 Softswitch User Manual

Cisco BTS 10200 Softswitch T.38 Fax Relay
Fax Analyzers
Sometimes it is necessary to go beyond the debugging capabilities of the Cisco voice gateways to resolve
fax relay problems. Tools such as protocol analyzers and fax analyzers are used to see what is occurring
during fax relay operation. Fax analyzers such as the Genoa ChannelProbe/FaxProbe by QualityLogic
or the HP Telegra can be positioned between the fax device and the gateway to capture what is occurring.
Protocol analyzers such as Sniffer and Domino can also be helpful when you need to view the fax relay
packets that are being exchanged between the gateways.
The ability to resolve a complex problem sometimes requires using a combination of test equipment—an
analyzer to capture the fax traffic at each fax machine and a protocol analyzer to capture the fax relay
packets. A single fax call is placed to reproduce the problem, and then the information is captured from
the attached devices for analysis.
Most fax analyzers have adequate help screens and documentation to help you determine what is
happening. The T.30 specification is also very helpful. For the protocol analyzers, decoding can be a
little more difficult since sometimes the encodings are proprietary or the analyzer software does not have
the specific decode needed. If the protocol analyzer is not able to decode the frame, the frame can be
manually decoded using the specification. With T.38 fax relay, a Cisco proprietary format is used for the
fax relay packets.
With fax analyzer and protocol analyzer information, you should be able to resolve most T.38 fax relay
problems. Few fax relay problems reach this point, and when they do, escalation and other resources
should already be involved for further assistance.

Opening a TAC Case

If this document has not enabled you to isolate and resolve the problem, open a case with the Cisco
Technical Assistance Center (TAC) and provide the following information:
•
•
•
•
•
•
•
•
Network topology description (PDF, Visio, or Microsoft PowerPoint format).
The fax machines used, including vendor and model information.
The history of the problem.
Useful information includes whether the implementation is new or an established network that
worked well and then failed.
If the network was established, what changed before the problem occurred? Is the problem
intermittent? Can the problem be reproduced and, if so, what are the steps to reproduce the problem?
Output of the show tech command from both fax gateways and all the routers on the IP path, and
relevant information for the active non-Cisco network equipment.
A pair of the call traces with the following debug flags enabled:
debug voip ccapi inout
–
debug vtsp all
–
debug isdn q931 (if the ISDN or Q.Sig is involved)
–
A pair of the show voice call and show voice dsp outputs. ·
A pair of the fax analyzer traces connected in the monitor mode to the originating and terminating
fax machines, if available.
Results of the troubleshooting and debugs already performed, if available.
Cisco BTS 10200 Softswitch T.38 Fax Relay Support
Troubleshooting Fax Relay
23