[reSIProcate] Re: Invite Session Questions

[Robert Sparks]

It is not explicitly illegal, but it isn't well understood what it 
means, particularly if the
redirection response contains more than one contact :).

There are bugs registered against this, and we're working through them.

The dialogusage draft says this:

    3xx responses: Redirection mid-dialog is not well understood in SIP,
       but whatever effect it has impacts the entire dialog and all of
       its usages equally.  In our example scenario, both the
       subscription and the invite usage would be redirected by this
       single response.

For our purposes - if we receive a redirect to a mid-dialog request 
that has one contact,
for the dialog state we can semantically we can treat it as a 
successful target refresh
request that had a different remote target. (and issue the request 
again).

I honestly don't know what DUM should do with a mid-dialog 3xx with 
more than
one contact. If its something we want to deal with right now, the API 
will probably
have to change to give the app using DUM some say in which contact gets 
chosen.
Otherwise we'll have to choose to do something suboptimal like tearing 
down the
usage/dialog or something hokey and probably broken like choosing the 
first one.

Thoughts?

RjS

On Mar 9, 2005, at 10:00 AM, Scott Godin wrote:

> Is it legal for mid-dialog requests to be redirected?  ie.  Can an 
> in-dialog re-invite or refer request be redirected by the far end?
>
>  
>
> Thanks,
>
>  
>
> Scott