Subject: Re: SIP Questions

From: [email-masked]
Date: Tue, 1 Feb 2000 15:01:49 +0530

1. Could a Server send me an De-Register message if he want (e.g. if he
wants to reboot)??

Arjun> Actually this issue did come up before and I think it was decided
then
Arjun> that its not important (however, I would have preferred if there
were a well stated
Arjun> way, which you could use if you want)
Arjun> I have a question- since INFO can carry any information, can I use
INFO for this purpose ?

2. Could a Server change the "Expires"- Header field (and therefore
 change the Register- Time)??

Arjun> Yes, the Registrar can select a higher value of Expires, but not a
lower one. (4.2.6, RFC 2543)

3. Did the Server send somthing as "Keep Alive" to the registerd
 UserAgent??(or did he make a "ping" to the IP or something else to
determine that my UA is still active)

Arjun> Is there any defined message for this from server-client ? Or is it
that inactivity
Arjun> can be figured out by other means (eg no RTP packets during call,
timeout, etc ?)

4. What happens if my UserAgent hangs up??

Arjun> In what state ?

5. Is there a generelly timout when the Server delets the
register-entry   (e.g. after 48 hours) ??

Arjun>  If nothing is specified in the REGISTER request, 60 mins is the
default (4.2.6, RFC 2543)

6. Did the server MUST send a "200 OK"- Response if the UserAgent send a
 De-register(REGISTER with Expires=0) ??

Arjun> Yes - This OK is to tell the sender that it received the REGISTER
message.
Arjun> You are probably wondering what happens if the client sends and
immediately exits
Arjun> without waiting for a response - then registrar transmits 200OK once
and stops anyway

Regds
Arjun
--
Arjun Roychowdhury @ Hughes Software Systems

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From: Igor Slepchin <[email-masked]>
Date: Tue, 01 Feb 2000 11:16:24 -0500

> lower one. (4.2.6, RFC 2543)

It's the other way around (a quote from 4.3.6 below):

A server SHOULD NOT use a higher lifetime than the one requested, but
MAY use a lower one.

---
Igor Slepchin