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Cisco Bug: CSCtd17854 - PGW doesn't forward 491 response to originating leg leading to no audio

Last Modified

Feb 07, 2017

Products (1)

  • Applications for Cisco Unified Application Environment

Known Affected Releases


Description (partial)


One-way audio followed by the call dropping or no audio followed by the 
call dropping. 


Occurs in a specific call flow where Cisco Unified CM is connected to the
PGW via a SIP trunk and the PGW is connected to a service provider using
SIP. The call flow that causes the problem is an attended transfer between
two call legs from the PSTN where the originators of both of those 
call legs are also coming from phones attached to a Unified CM.
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Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
  • Severity
  • Known Fixed Releases
  • Related Community Discussions
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