6 Feb
2007
6 Feb
'07
10:08 a.m.
Hey Guys,
Is it mandatory for SIP servers to generate to UA 180 Ringing to inform them that the called party is now ringing ?
The reason i'm asking is because I am seeing strange results using different UAs.
Using SIP clients to call out , instead of seeing 180 Ringing , i see 183 session progress even before call was picked up.
On some sip client , ring back can be heard. On some others , ring back cannot be heard.
Is there any reason to suspect that these UAs needs to receive 180 Ringing before generating any ringback ?
Regards, Sam