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Cisco Bug: CSCur32841 - Audio 'm' line is stripped in 200OK while answering to the T.38 ReInvite

Last Modified

Apr 17, 2020

Products (1)

  • Cisco Unified Communications Manager (CallManager)

Known Affected Releases


Description (partial)

The SIP Calls might fail. In the traces, you can find that the ReInvite for the T.38 negotiation contains active audio and fax 'm' lines in SDP but the 200OK for the ReInvite from CUCM will contain only Fax 'm' line.

T.38 Fax negotiation (The CUCM would be involved for the calls from/to PSTN). Presently, CUCM does not handle
fax and audio call concurrently. CUCM can handle the scenario where first mLine is Fax and second mLine is active audio
 but the reverse it cant handle,i.e, first mLine is active audio and second mLine is Fax
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