inline.
Victor Paulsamy wrote:
>>-----Original Message-----
>>[mailto:[EMAIL PROTECTED]]On Behalf Of feng zhang
>>Subject: [Sip-implementors] Stateful Proxy
>>
>>
>>Hi All,
>>
>> Can a Stateful Proxy do that in the scenario below:
>>
>> User A Stateful Proxy User B
>> | | |
>> | BYE | |
>> |--------------------------->| BYE |
>> | |--------------------------->|
>> | | 200 OK |
>> | |<---------------------------|
>> | 200 OK | |
>> | X <----------------| |
>> | line is down and User A does not receive 200 OK, so
>> | User A resends BYE |
>> | |
>> | BYE |
>> |--------------------------->|
>> Here, once a stateful proxy receives a retransmitted BYE, can the
>> proxy sends 200 OK to User A ? or the proxy still delivers
>> the BYE to User B, and let User B resend 200 OK?
>>
>> Thanks a lot to give me an answer!
> BYE will be proxied by the stateful proxy towards User B. User B will
> generate 481. The proxy may issue its own respone (based on 481) or simply
> forward 481 to User A.
Another interpretation (and one which I am partial towards) is that
since the proxy is stateful and it did see a final response from User B
(except that it got lost in transit to User A), it will re-transmit the
final response when it gets the second BYE. The second BYE will be
recognized as a retransmitted request and will elicit the 200 OK. Since
a stateful proxy will maintain transaction state for 64*T1 seconds after
sending a final response over an unreliable transport, I don't see
the need to proxy the BYE request anew to User B (rfc3261, section 16.2,
paragraph 2 and section 17.2.2).
Note that this behavior is NOT true for 200 OKs to INVITEs, since the
reliability of these is end-to-end.
- vijay
--
Vijay K. Gurbani vkg@{lucent.com,research.bell-labs.com,acm.org}
Wireless Networks Group/Internet Software and Services
Lucent Technologies/Bell Labs Innovations, 2000 Lucent Lane, Rm 6G-440
Naperville, Illinois 60566 Voice: +1 630 224 0216
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