[VoiceOps] SIP OPTIONS PING

[Jared Geiger]

>
> In my observations, the contents of the SIP options response has no
> bearing. In fact, an error response (such as "not supported") is sufficient
> to keep the sip binding up, if I recall correctly.
>

You will also have the joy of making sure your providers support SIP
options. Depending on the provider I get any one of these back: 501,
403, 484, 404, 405, 408, 502. Some just plain don't respond, but the
big guys do usually respond.