Subject: Question about REGISTER

From: "Christian Jansson" <[email-masked]>
Date: Mon, 7 Feb 2000 09:07:27 +0100

From 4.2.6:

All current registrations MUST share the same action value. Registrations
that have a different action than current registrations for the same user
MUST be rejected with status of 409 (Conflict).

1.What about a REGISTER request that does not have an action value:
   Does that match any of "redirect" or "proxy"?
   Is it then up to the server to chose the action, and indicate the choice
   in the response?
   Or is it the first REGISTER with an action that sets the rule (also for 
   earlier REGISTERS that did not have an action value)?

2. Why do they have to share the same action at all?

3. A server that only supports one of the redirect/proxy behaviors receives
    a REGISTER with the unsupported action indicated. What is it supposed
    to do, send a 409 response?

--
Christian Jansson ([email-masked])
HotSip AB
phone:  +46 (0)8 555 10 704
mobile: +46 (0)70 558 1038

---

From: Jonathan Rosenberg <[email-masked]>
Date: Mon, 07 Feb 2000 09:57:14 -0500

>    earlier REGISTERS that did not have an action value)?

If no action is present in the initial registration, the server does
whatever it likes and returns that in the response. From the spec:

>  action: The "action" parameter is used only when registering with the
>         REGISTER request. It indicates whether the client wishes that
>         the server proxy or redirect future requests intended for the
>         client. If this parameter is not specified the action taken
>         depends on server configuration. In its response, the registrar
>         SHOULD indicate the mode used. This parameter is ignored for
>         other requests.

Subsequent registrations with no action will take the same value.

> 2. Why do they have to share the same action at all?

It doesn't make sense for them not to. If a server has two URLs, one
with proxy, and one with redirect, and then an INVITE comes, what does
it do? Does it ignore the proxy and then redirect? Would it redirect to
one or the other or both URLS? Would it first proxy, and then on
failure, redirect? These are the kinds of things CPL can specify. Rather
than build arbitrary and complex meaning into the action parameter, we
kept it simple.

>     to do, send a 409 response?

403 Forbidden is probably better. It doesn't much matter, unless you
want to have the client resubmit the request with a different action
tag. There is currently no way to do this; I'm not sure its a big deal
(tend to think its not generally needed)

-Jonathan R.
-- 
Jonathan D. Rosenberg                       200 Executive Drive
Chief Scientist                             Suite 120 
dynamicsoft                                 West Orange, NJ 07052
[email-masked]                     FAX:   (732) 741-4778
http://www.cs.columbia.edu/~jdrosen         PHONE: (732) 741-7244
http://www.dynamicsoft.com