If you still think SIP trunking is primarily about cost savings -- guess what? You're still right. The conventional wisdom on SIP trunking was expected to shift over time, in a classic new-technology ...
来自MSN

What Is SIP Trunking?

Session initiation protocol (SIP) trunking allows any organization to upgrade its offline PBX to an internet-powered business phone system. Business leaders are using this technology to harness VoIP’s ...
SIP Trunking is maturing. The lack of standard implementations has slowed adoption, though I fully expect the pace to accelerate given the cost savings and support of technologies such as UC and video ...