On 10/6/17 2:42 PM, VARUN BHATIA wrote:
Hello,
As a B2BUA what is the expectation when it is sitting behind a forking
proxy (IMS Application Server) and it is sending back multiple early
dialogs back.
1. It should ideally send it back transparently to ingress i.e.
creating multiple early dialogs at ingress leg too. (UAC should be
capable of supporting early dialogs)
IMO this is the straightforward thing to do.
2. Doing inter-working with ingress and rather than sending multiple
early dialog toward ingress it should send new offer in UPDATE.
(Though in this case UAC should support UPDATE method in early
dialog).
I realize (sadly) that there may be some UAs that don't properly handle
multiple early dialogs, and some B2BUAs may want to make them work by
handling the complications for them. OTOH, doing anything other that (1)
is tricky. The guiding rule is that the B2BUA must follow all the rules
for a UAS on the ingress side and (independently) for a UAC on the
egress side. There really aren't any other rules. Be as creative as you
like.
In the above scenario if Pre-condition is been expected then will
there be any change or it should be same.
As per my understanding forking proxy should handle, in this scenario,
once the pre-condition has been exchanged & resource reservation has
been done. AS should not send multiple early dialog towards B2BUA.
Preconditions could make this very difficult to do.
Though i am trying to find reference in RFC or 3GPP standard but not
yet able to find any.
I'm not at all up to date on what in in 3GPP standards. But frankly I
would be very surprised to find anything.
Thanks,
Paul
Your expert inputs are much appreciated and if it can be provided in
some reference to standard it will be very helpful.
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