Locating the final negotiated Codec in SBC Traces for VoLTE Calls

[Kashif8860]

Hi Experts,

Can anyone guide me on where to check the final negotiated codec in the trace on an SBC?

VoLTE to VoLTE Call

Thanks!

[mtanis]

You can find it in the Session Description Protocol (SDP) messages within SIP signaling.

Typically, it appears between the INVITE and the SIP 200 OK messages.

In rare cases, it may be included in the ACK confirmation. After this exchange, you should see the codec selection.

[maliseker]

Additionally, the 183 Session Progress message is also commonly used to carry the SDP answer.