GLSIP utilizes Voice over Internet Protocol (VoIP) technology to deliver quality business communication services. Traditionally, major service providers use Time Division Multiplexing (TDM) trunks to allow corporate PBXs to interface with the Public Switched Telephone Network (PSTN). However businesses are now eagerly embracing the convenience and cost savings of Session Initiated Protocol (SIP) as a unified solution for transmitting voice, data, and video signals consistently, securely, and effortlessly.