In my test scenario, asterisk (h323)->cisco gateway, only g711ulaw allowed. The cisco gateway always sends fastconnectrefused for setup messages with faststart from asterisk.
I studied this issue and found h323 channel driver sets g711ulaw capability to max_ms, 150. The cisco gateway rejects faststart. After I changed the code to set g711ulaw capability to def_ms, 20, the cisco gateway accepts faststart.
Would anybody please tell me if the codec capabilities are configurable or hard coded in h323 channel driver? I mean using max_ms, min_ms or def_ms.