Firstly, we should understand about the absent service flow and how the end user experience this service. The Absent service is belonged to Called party service. When the service is enabled, anyone call the Service parties will hear announcement that currently he is not available or away for certain business. This Service does require ATS and MRP to perform announcement playing.
In order to start troubleshooting and analysis, we can setup the service test call scenario and capture the signal trace on ATS by using the “Subscriber IMPU” and fill in the User number which subscribes the Absent Service. CSCF trace can be setup base on User number for further analysis purpose as well.
Test call need to be performed to capture the message for analysis and found that 500 internal error message (Warning: 399 198.sjaatshw01.ims.tm.com.my.772 "Internal error"
) was received.
To ensure the tone can be played successfully, check the INFO message. The first INFO message is shown which “Tone ID 111” is requested to be played by ATS to MRP. The command of “LST MRFTONE” is executed in ATS MML to check whether the “Tone ID 111” is correct request send to MRP via MRFC.
Check the Second INFO and found that a failed play message is displayed.
Base on the analysis result obtain from the previous steps, we can conclude that this failure is due to tone file failed to be played the announcement. Therefore, the error may occur on MRFC or MRP. Since there is no alarm for the connection failure between the ATS and MRFC or MRFC and MRP, this error can be occurred due to Media file missing in MRP.
Login to MRP MML and execute DSP TONEFILE and do a mapping will result on ATS query (LST MRFTONE) and found that few media file missing range from 111, 112, 160~167 and all this media file is used for Absent service.