Re: [sipcore] 4028bis: forking

[OKUMURA Shinji <[e-mail]>]

Hi,

If Bob is a call center operator, I think that's a problem for him.

If Carol responds 401, which is the "best" final response?
At least for session-timer, I think it should be handled within the early dialog as well as the pre-condition. (If we didn't have to consider backward compatibility.)

Regards,
Shinji

On 2020/05/28 10:59, Dale R. Worley wrote:
> OKUMURA Shinji <[e-mail]> writes:
>> In following scenario,
>> (1) Alice sends INVITE.
>> (2) Proxy1 forks INVITE to Proxy2(for Bob) and Carol.
>> (4) Proxy2 rejects INVITE by 422.
>> (6) Carol accepts INVITE by 200.
>>
>> Eventually Bob never receive INVITE.
> 
> True ... but that's acceptable.  Alice sent an INVITE and connected with
> one if its destinations.
> 
> A more interesting issue is if Carol does not accept the INVITE, and her
> UA responds with 487.  Then Proxy1 sees a 422 response from Proxy2 and a
> 487 from Carol.  If it returns the 487 to Alice, Alice won't update
> the session timer.  RFC 3261 sectoin 16.7 item 6 says
> 
>           The proxy SHOULD
>           give preference to responses that provide information affecting
>           resubmission of this request, such as 401, 407, 415, 420, and
>           484 if the 4xx class is chosen.
> 
> which suggests that 422 should be returned to the UAC, because the UAC
> can adjust the request based on it.
> 
> Dale
>