Session Initiation Protocol (SIP) and Signaling System 7 (SS7) are the
> common protocols used for transmitting voice across networks. Just how
> they work with VoIP ... or not ... opens the door for both concerns and > opportunity.
> You can read the rest of this article here:
>formatting link
Interesting article, but I'm not sure I agree with 'SIP ... does not use a separate signalling path', in that the media certainly need, and usually does not, follow the same path as the SIP dialogs.