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Hi All,
Please help me for the following race condition
scenario...
UA1
B2BUA
UA2
|
INVITE
|
INVITE
|
|---------------------------->|------------------------->|
|
|
|
|
180
| 180
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|<----------------------------|<-------------------------|
|
| 200
|
| CANCEL 200
|<-------------------------|
|---------> <---------| (race
condition) |
|
200
|
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| <------------
|
|
|
CANCEL |
|
| ------------>|
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When a UA1 sends INVITE to a B2BUA (or statefull Proxy) which than
forwards it to UA2.
UA2 answers by sending 200 OK which B2BUA forwards to UA1 , but
before receiving 200 OK UA1 sends CANCEL. In that case
Q1.What will UA1 do when he receives 200 OK after sending
CANCEL?
Will UA1 ignore 200 OK or will he send some 4xx
(say 403) response for CANCEL?
Q2.What should B2BUA do ? Should he send CANCEL to UA2 or he
should send ACK (for INVITE) and than BYE to UA2?
Q3. WHat will a terminating UA2 do if he sends 200 OK and
immidiatly after that receives CANCEL(rather than getting ACK)?
In other words,
Will B2BUA (or statefull proxy ) accept CANCLE after sending 200
OK(answer) and forwards it to termitaing UA?
or B2BUA will ignore it?
or it will send 200 OK (for CANCEL) and 487 Response(for
INVITE) to UA1 and on the other side It will send ACK(for INVITE) and then
send BYE to UA2?
Thanks for advance.
regards,
Sushil
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