[OpenSER-Devel] Fwd: SIP ping and usrloc

Johansson Olle E oej at edvina.net
Fri Jul 4 08:14:30 CEST 2008

> Hi *,
> Is there already functionality within OpenSER to make sure that a  
> contact is actually alive. i.e. UA registers and slightly afterwards  
> drops off the network. Now when UA is called by UA2, there is  
> silence as the SIP packets are sent to UA -  which now doesnt exist.
> I would like to implement some functionality in usrloc to do a SIP  
> ping (maybe using OPTIONS) before returning a contact making sure  
> the contact is 'alive'?
> any other ideas?

OpenSER has a NAT keepalive function that sends requests to keep the  
NAT IP flow open, but not to keep status as far
as I know.

Asterisk has the functionality you need, where it use an OPTIONs  
message to monitor the latency and
status of the UA.

Maybe this is something that could be added to the presence modules in  


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