All,
I am looking for some input for the
following scenario please:-
This is involves a TCP INVITE from UAC to
proxy A – which is then proxied to proxy B
– then to UAS.
UAC
P1
P2 UAS
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| INVITE
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|-------------->|
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| 100 TRYING |
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|<--------------|
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| INVITE
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|-------------->|
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| 100 TRYING |
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|<--------------|
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| INVITE |
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|-------------->|
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| 180 RINGING |
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|<--------------|
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--------------------PROXY A fails after
INVITE has been sent to Proxy
B-------------------------------------------------------
THEN:-
- The UAC has detected the TCP transport failure and is
attempting to contact another server for the request (AS per SRV failover
rules). It terminates the
transaction and issues another INVITE to proxy P1' which
is part of the P1 cluster.
- During this process, Proxy P2 has used the SRV
record in the via and routed the response back to
the UAC via Proxy P1''. The UAC will receive the response,
but have no record of it’s existence and
thus will not ACK it.
- The second INVITE has since arrived at the UAS, which
identifies this as a merged request and creates the
appropriate "Loop Detected" response, which is routed back
to the UAC. The result is that
the call fails at the UAC.
Thanks in advance for any input,
Chris.
------------------------------------------------
Chris Boulton
Ubiquity Software
Tel : +44 (0)
1633765600
Fax : +44 (0)
1633765601
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