Its also possible for the proxy to recurse on some of the alternatives,
and then return a 300 containing some that it chose not to try itself.
But an all-or-nothing approach by the proxy is much more likely.
Thanks,
Paul
Iñaki Baz Castillo wrote:
> El Miércoles, 6 de Mayo de 2009, Vito Korleone escribió:
>> Hi to all SIPers,
>> I think my question is simple, if A sends an INVITE to a B passing the
>> INVITE of course from a proxy or BBUA.. Whatthe proxy should return to A if
>> B response is 300 Multiple Choices with 2 Contacts?
>
> When Proxy receives a 300 from B it can do two things (depending on its local
> policy/configuration):
>
> 1) Reply the same 300 upstream to A, so A would (if the user wants) call to
> the first Contact in the 300, later to the second if first doesn't reply...
>
> 2) The proxy could perform "recursion", this is: the proxy takes the URI's
> from the Contact received in the 300 reply and adds these URI's as new
> branches so sends there the request.
>
>
>> Should the proxy notify
>> A for trying to connect him somewhere? If he don't probably atimer will
>> expire?
>
> I didn't understand the above question.
>
>
>> And if we have many Contacts and BBUA needs time to try them?? What
>> happens then?
>
> What does mean "B2BUA needs time to try them"??
>
>
>> Oh and something else relative to 300.. When do you think the
>> proxy or BBUA should try thesecond or generally next Contact in the 300?...
>
> It depends on "q" parameter in each Contact URI (priority). Read about "q"
> parameter in RFC 3261.
>
>
>> if the response of the a tried Contact is 4xx 5xx or 6xx?
>
> At this point I strongly recommend you just to read the secion about "Proxy"
> in RFC 3261, it explains all your questions clearly. Don't waste time trying
> to guess them.
>
>
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