What is a SIP?

SIP stands for Session Initiation Protocol and is used for internet telephony signalling including desk phones connected via Ethernet RJ-45 connections. SIP is also supported by most mobile Apps for making calls over a data connection and can be used over Ethernet or WiFi. The advantages of the SIP protocol is its simplicity. SOP uses the UDP port 5060 as standard but can also work on TCP/5060. See RFC3261 for more information on the protocol.