Hi,
There was a discussion on this some time ago, and the general understanding is that it IS allowed to send INFO before the UAC has received the 200 OK response and sent the ACK. However, unless the UAC has received a 18x provisional response, with a To header tag and Contact header to use in the INFO, it can NOT assume that proxis will handle/route an INFO in the same way as the INVITE. For this reason it may (depending on the scenario you want to use INFO for) be better if the UAS sends a 18x provisional response, instead of 100 Trying, when it receives the INVITE, to make sure the UAC gets the To tag and Contact header as soon as possible. They are also needed if the UAC wants to terminate the specific call setup leg using BYE. Regards, Christer Holmberg Ericsson Finland Sarju Garg wrote: > > Hi all, > > If the user sends a message that is not expected during the call state > ,then how should UA behave to this message? FOr example if the calling > side UA sends INFO while the call is being established (UA sends > INVITE and then INFO without waiting to send ACK first), then how the > does called side UA interpret this INFO message. There are 3 > possibilites: > 1. Ignore it, will be retransmitted after sometime > 2. Save it, send 1xx message and process it after receiving ACK > 3. Send 409 message saying that this message is received at wrong > time. > > To me, 2 seems to be the right option. Please let me know which would > be the correct behavior. > > Thanks > Sarju _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
