What is SIP?
Session Initiation Protocol (SIP) is the set of rules that allows you to initiate and terminate a communication session, whether it’s a voice call between 2 people or multiple calls between a whole team, using an IP address.
SIP is generally the best alternative to ISDN since the announcement of the phase-out as it is cheaper on a per line basis. SIP offers control over your phone numbers and it is quicker to install.
What is SIP Trunking?
SIP trunking (also commonly referred to as a SIP Phone Line) is the service that allows you to put the SIP protocol (a set of rules that allows you to initiate and terminate a communication session) into use on a public network.