SIP VoIP

Voice over Internet Protocol (VoIP) is one of the fastest emerging technologies on the planet, and it is revolutionizing the way the world communicates. Like any new technology, VoIP has gone through some growing pains since it was first used in 1995. After beginning life as a computer to computer communication method, VoIP has now evolved to the point where standard telephones hooked to a VoIP adapter can be used, without even having a computer hooked up to your Internet connection!
Another area where VoIP has evolved is in the protocols, or agreed-upon interfaces, used in coding, terminating, and transmitting voice data packets. Although no clear winner has emerged, Session Initiation Protocol (SIP) is one of the strongest protocols yet developed for VoIP. SIP VoIP offers a number of advantages over other protocols, having been adopted by industry leader Microsoft. SIP VoIP operates within the Internet domain, although gateways can connect a SIP VoIP telephone to the public service telephone network (PSTN) in most countries.
SIP VoIP works by "dialing" a proxy server to connect with a user on an IP network. Instead of using a telephone number, however, the SIP VoIP phone will use an IP address to locate the user you want to call. Because most IP addresses are dynamic (changing) rather than static (fixed), SIP VoIP also can "look for" a username on an IP network. Once it finds that the other party's SIP VoIP phone is hooked up, it connects the two users or forwards the caller to voice mail (or sounds a call waiting tone) if the other party is already on the phone.
One of the exciting things about SIP VoIP technology is its portability. SIP VoIP hardware is simply a telephone adapter that hooks up to a broadband Ethernet port. SIP VoIP users, therefore, can take their telephone anywhere in the world and receive local calls (from within their home area code) for free! This is because once the phone is connected to the Internet, it does not know (or care) whether it is in your hometown or in the middle of the Sahara Desert. It simply logs onto the 'net and tells the SIP VoIP provider that it is online.
With this kind of portability, as well as the significant cost savings it offers and the ability to make the most out of a broadband Internet connection you already pay for, SIP VoIP seems poised to take the lead in the competitive world of VoIP.