SIP Overview
Implementing an IP PABX with SIP trunks can offer significant cost-savings for most enterprises by eliminating the need for ISDN BRIs (Basic Rate Interfaces) or PRIs (Primary Rate Interfaces). For a successful deployment of SIP trunks there are three components necessary: a telephone system (PBX) with a SIP-enabled trunk side, an enterprise edge device understanding SIP and an Internet telephony or SIP trunking service provider.