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Cisco Bug: CSCum43773 - Glare condition resulting in one way audio

Last Modified

Feb 25, 2019

Products (6)

  • Cisco Unified Communications Manager (CallManager)
  • Cisco Business Edition 6000 Version 8.5
  • Cisco Business Edition 5000 Version 8.5
  • Cisco Unity Connection Version 8.5
  • Cisco Business Edition 6000 Version 8.6
  • Cisco Unified Communications Manager Version 8.5

Known Affected Releases

8.5(1)

Description (partial)

Symptom:
Intermittent one way audio calls with the following call flow.

h323 GW->CUCM Cluster 1->SIP->3rd party IVR

IVR performs refer transfer to an Attendant Console on Cluster 2. Call flow becomes:

h323 GW->CUCM Cluster 1->SIP->CUCM Cluster 2->Attendant Console->SCCP ip phone

Problem happens after the call is transferred to the ip phone on Cluster 2. The caller can hear the user at the ip phone, but the user cannot hear the caller.

Traces show when the user on cluster 2 answers, a re-INVITE is sent from cluster 2 to cluster 1.  Cluster 1 is also sending a re-INVITE since the previous exchange had dummy ports sent to cluster 2 from cluster 1.  For example:

09:57:48.182 | 
H245ASN - TtPid=(309155) -Outgoing #5072749 -value MultimediaSystemControlMessage ::= response : openLogicalChannelAck : 
{ 
forwardLogicalChannelNumber 10, 
forwardMultiplexAckParameters h2250LogicalChannelAckParameters : 
{ 
sessionID 1, 
mediaChannel unicastAddress : iPAddress : 
{ 
network 'AC100114'H, 
tsapIdentifier 4000 
}, 
mediaControlChannel unicastAddress : iPAddress : 
{ 
network 'AC100114'H, 
tsapIdentifier 4001 
} 
} 
}

This results in a glare condition.  491 Request Pendings are sent from both clusters.  The glare is recovered just fine, but on cluster 1 h245 is never renegotiated so the dummy port is never updated to the correct port.  This results in one way audio.

For working calls, this glare condition never occurs.

Conditions:
Call flow that triggers this issue.

h323 GW->CUCM Cluster 1->SIP->3rd party IVR

IVR performs refer transfer to an Attendant Console on Cluster 2. Call flow becomes:

h323 GW->CUCM Cluster 1->SIP->CUCM Cluster 2->Attendant Console->SCCP ip phone
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Bug Details Include

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  • Status
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