RTP Not Reaching Phones on SIP Trunk Calls

Scenario

Outbound calls to some mobile's that are switched off or out of coverage and have no voicemail configured then the network announcement is not played. This is carrier specific and due to the way media is delivered by that mobile carrier (EE and Vodafone) back to the SIP carrier.

It would appear that when media is delivered to Ingate by the SIP carrier it is in turn delivered to the Vtrunkswitch. The handset remains connected to Vphoneswitch which has signalled but no media path is ever established with Vtrunkswitch. 

Symptoms

Cause

SendEarlyMedia is on in the SIP profile

Resolution

Description:
On Outbound calls only: some EMEA mobile companies send a 403 forbidden (EE and Vodaphone) if there is no voicemail box configured on the mobile account, and the mobile is physically turned off.

What:

We cannot hear the carrier message and we get a "Action not permitted" on the telephone (P-series and MGCP phone.)

Fix:

In the SIP profile change "SendEarlyMEdia" to 0.

What IF:

If they have ShoreTel call recorder, then they will want to set SendEarlyMedia to 0, and change the server settings to "Wait for far end to answer on outbound calls".

If they have Oaisys, then they will need to contact Oaisys to find out how to have Oaisys to only start recording when the far end answers.


ShoreTel Call Recorder Screen shot:

ST Call Recorder Screenshot


Article: 000009846