>>>>> ?????? <[EMAIL PROTECTED]> wrote: > As shown in title, my question is when UAC has to re-send REGISTER message to > refresh its binding in REGISTRAR? Let's say that UAC has received 200 OK > meessage whose expire parameter value in Contact header is 3600. I think I > have read somewhere in RFC which says subsequent REGISTER message should(?) > be send at the time when half of the expire value in 200 OK is elapsed. > Unfortunately I don't know exactly where I have read this, and all I find now > is that UAC is supposed to send REGISTER message simply before expire > interval elapses (RFC3261 10.2.4). Isn't there anybody who can clearify this?
Before expiration-64*T1, but no earlier than expiration/2. Of course, there is no exact specification, but I try to follow existing traditions and common sense: 1. There is no need to issue re-regisering request earlier; instead, the latest possible moment shall be used. (Otherwise, expiration negotiation was invalid and one should either change server or client setup.) 2. In DHCP (another well-known and mature protocol with client registration), lease request should be issued after 1/2 of lease expiration interval. This doesn't add too much useless load, but allows to deal with temporary network problems. 3. As soon as client should be re-registered before its expiration, client should give enough time for server and network to deal with request. The maximal allowed time for this is 64*T1, according to paragraph 17.1.2 (Non-INVITE Client Transaction). So, request should be issued before expiration-64*T1. -- Valentin Nechayev PortaOne Inc., Software Engineer mailto:[EMAIL PROTECTED] _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
