A google search (June 2009) on a ‘SIP Trunking’ returns ~500k
references. From Wikipedia (replace ‘connection’ with Trunk) A
SIP (Session Initiation Protocol) connection is a service
offered by many ITSP (Internet Telephony Service Providers) that
connects a company’s PBX to the existing telephone system
infrastructure (PSTN) via Internet using the SIP VoIP standard.
This probably is the most common understanding of SIP Trunking –
that being, a SIP-based interconnection from a SIP-based IP-PBX
to a SIP Service Provider which facilitate communications to and
from the PSTN. Within this context, there’s ample evidence to
the value of SIP Trunking. The first, and probably most obvious
advantage is a reduction of costs by leveraging IP as the mode
of communications between the Enterprise and the Service
Provider. Historically, businesses had two distinct and separate
network infrastructures – one for data, and another for voice.
Maintaining one is easier (but a little bit more complicated at
times) than two. If do