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Incoming calls from PSTN via MGCP gateway failing


Incoming call coming via PSTN through a 10 channel fractional E1 reached the destination number through an MGCP gateway and gets dead air. When redialled, the call goes through.

Calling Number: 427341490
Called Number : 77076

Attached is the CUCM traces

2 Replies 2

Sreekanth Narayanan
Cisco Employee
Cisco Employee

Did the first call made ring the phone? Was the call answered and then dead air experienced?

If the call connected, that would mean the signaling was fine and the RTP needs to be investigated.

Manish Gogna
Cisco Employee
Cisco Employee


I had a quick look into the trace, after the phone goes off hook we see an important message

11/26/2015 15:33:44.927 CCM|StationInit: (0004482) OffHook.|<CLID::DWNR-CUCM><NID::nryd-cm01><CT::2,100,39,1.580767285><IP::><DEV::SEP00070E57571A><LVL::State Transition><MASK::0020>

11/26/2015 15:33:44.930 CCM|MGCPpn9d:star_MGCPModifyConnection - No change in connectionMode and localConnectOpt since last MGCP message sent from CM to gateway. Save this MDCX.|<CLID::DWNR-CUCM><NID::nryd-cm01><CT::2,100,132,412964.1><IP::><DEV::><LVL::Significant><MASK::2000>

Basically we do not see any MDCX for this call. There was a bug filed for this exact message but it involved an incoming call that was redirected to the final destination, not a direct call to the called party

If you can try changing the service parameter mentioned in the bug in service parameters advanced option it will help rule out the above bug.


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