Because SIP costs less, provides better redundancy solutions, and now that it is being delivered from the top Carriers in the business it is just as reliable.  That being said there are plenty of SIP providers that will provide you with SIP Trunks over the open internet.  Stay away from these carriers as you cannot control the quality of a call that travels over the open Internet.  

The bottom line when choosing a SIP provider is to just make sure that they are providing your SIP dial tone over dedicated connections with QOS (Quality of Service) being supported from end to end.    SIP supports Direct Inward Dialing, ANI (caller ID) and the ability to control your outbound caller ID as well. 

The true beauty of SIP is that you can also have multiple inbound routes from your SIP Carrier.  Thus if one of your connections goes down you can automatically reroute calls over a failover connection.  This is one the biggest reasons that businesses are flocking to SIP Dial Tone.   

We can help you design the right SIP solution for your business.  Contact us today!