Subject: RE: A few questions on REGISTER

From: "Donovan, Steven R." <[email-masked]>
Date: Tue, 28 Sep 1999 16:13:08 +0000

[email-masked] [mailto:[email-masked]] wrote:

...<snip>

Well, the problem was that since we are saying (according to the RFC) that
REGISTER messages are not rejected (ie no bad request is given), then in
the case when the REGISTRAR gets two messages from a UAC (the UAC did not
wait for a reply for register), 1st one is with Expires 0 and Contact * and
the following one is Expires <xx> and Contact abc, that means the client
wanted to remove all exisitng rgistrations and start afresh.
However, if they arrive out of order, that would mean add abc to the
register list and then remove all of them - something which was not
intended, but will happen since the registrar does not care about CSeq
ordering.

So if we are saying that since the client itself did not wait for the first
response, it should be ready for unpredicatable results, then the registrar
need not worry - but I did think it would just be safer if the registrar
did.

SRD> It seems strange to build a client that would not wait for the response
to the first register, but even if this is done, the registrar will inform
the client of the current registration status, in the form of a contact
list, in the response to the register message.  If it doesn't match the
user's expectations that a new register message can be sent.

<snip>...