SIP-addressing is logical, of the same type as URL in HTTP. And the most natural – to use the electronic mail as the SIP address. There are permissible varied parameters by the address: for example, it is possible to indicate the regular city telephone number, additional telephone, and the parameters of modem connection etc.
uVOIPit is a retail international VoIP service and wholesale VoIP termination business. It started in February 2010, and LLC licensed in April 2010. Website: http://www.uvoipit.com