The Session Refresh is sent just as a keep alive mechanism when a session Timer has been set up through negotiation. This would help the Proxies in the signalling path to know whether the UA's which have established the dialog are still active. The Proxy will release the resources for the call , if the session is not refreshed within the specified time. The UA's might know whether the other side is active , through the RTP or media they are recieving, but the Proxies do not. So the resources are not released at the Call stateful Proxy if a UA does not send a BYE and goes down, to enable a Proxy to detect such conditions a Session Refresh Request is used. have a look at this link: http://ietf.levkowetz.com/drafts/sip/session-timer/draft-ietf-sip-session-timer-14.txt I'am not sure whether it is latest. HTH, Cheers, Simith
vivek srivastava <[EMAIL PROTECTED]> wrote: Hi Senthil, In which condition UA should refresh session even if there is no change in session parameters? Vivek On Thu, 01 Jul 2004 senthil vinayagam wrote : >Yes, Re-Invite for session refresh should contain SDP even if the session parameters >doesn't change. Update can also be used for session refresh. >regards >Senthil Vinayagam >On Wed, 30 Jun 2004 Ramachandran Iyer wrote : >>I believe Yes.. >> B'cos you would specify the needed change of your session, through the SDP >> (session description). You might intend to change 1 of the session attributes ..say >> the codec (compression rate) or the port at which media is being received etc.. >> >>Rama >> >> >>Madhav Bhamidipati <[EMAIL PROTECTED]> wrote: >>Is SDP body required in reINVITE for session refresh? >>_______________________________________________ >>Sip-implementors mailing list >>[EMAIL PROTECTED] >>http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors >> >> >>--------------------------------- >>Do you Yahoo!? >>Yahoo! Mail is new and improved - Check it out! >>_______________________________________________ >>Sip-implementors mailing list >>[EMAIL PROTECTED] >>http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors >_______________________________________________ >Sip-implementors mailing list >[EMAIL PROTECTED] >http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors Yahoo! India Careers: Over 50,000 jobsonline. _______________________________________________ Sip-implementors mailing list [EMAIL PROTECTED] http://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
