[Serdev] Concept for a SIP cluster implementation

[Greger V. Teigre]

>>> Jan Janak wrote:
>>>
>>>>   - A user agent does not have to send INVITE messages through the same
>>>>     proxy instance as REGISTER messages. The proxy server that received
>>>>     the INVITE request can make sure that the uac is reachable
>>>>     for the duration of the transaction by retransmitting the
>>>>     provisional response periodically (simulates NAT ping). All other
>>>>     transactions finish immediately and do not need this.
>>>
>>>
>>>
>>> What happens in the callee hangs up (send the BYE)? This will be 
>>> loose-routed via the same proxy, which may not have a pinhole to 
>>> traverse the NAT :-(
>>
>>
>> Not if the proxy which receives the first INVITE from the caller sets a 
>> record-route and NAT-pings the caller until the BYE is received. But this 
>> would require some sort of dialog-stateful mechanism.
>
> So, we just have to make ser call-stateful first :-)

Would it be possible to save the location of nated INVITEs in the EP and 
then just use a FIFO location delete command sent to the EP from the ser 
receiving the BYE ?  We would then only need a way for the back-end ser to 
send the FIFO command.

g-)