[Freeswitch-users] SIP OPTIONS pinger

I want to get an idea of how well connected my fs boxes are to certain SIP servers that we use. The idea might be to send a SIP options packet to a remote address and time how long it took to respond. I suspect that fs can do something like this, but I was also wondering if there exists an off-the-shelf Linux package (a bit like mrt) that can do this. Failing that, some code in (say) PHP that can do it? I would have some kind of scheduled job that would send out a SIP options packet every 10s or so and keep track of the rtt.