based on your experience and expertise what would you say is the best sip trunk service provider out in the market and why? thanks
If you are in a major metropolitan area in the US, Cbeyond is pretty great. They only sell bundles though (i.e. Internet, SIP trunks, mobile phones, etc.) delivered via dedicated T1 circuits. They are a good price and feature set for small businesses and work perfectly with Cisco and other systems. They do not do "a la carte" SIP trunks though.
These are the cities they service: Atlanta, Chicago, Dallas-Fort Worth, Denver, Detroit, Greater San Francisco Bay Area, Houston, Los Angeles, Miami, Minneapolis/St. Paul and San Diego
Here is info about their SIP product: http://www.cbeyond.net/services/sipconnect.htm
Any SIP trunks delivered over the general Internet cannot guarantee any level of qos. For these services you would be best going with a name and company you can trust. Skype for SIP, for example? or Gizmo5?
I think cbeyond have a great service and quality but unfortunately they dont offer the ability to provide you with remote DID's, is only local did's depending of the location of the T1.
I have had great success with a carrier called RNK Telecom (www.rnktel.com). I've worked with them for over four years now. In the beginning they had their challenges but today they are very reliable and their technical support is strong and very responsive. They are based in the Northeast (Massachusetts). They offer DID origination and termination services with multiple levels of pricing based on least cost routing and premium services. I've worked with several carriers and RNK is the most impressive SIP carrier that I've run across so far.
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