How to use SIP over TCP

UDP Versus TCP for VoIP - OnSIP Why UDP and TCP Matter for VoIP. UDP and TCP protocols come into play with VoIP because they structure the way web traffic travels through the Internet. TCP and UDP packets are sent from a source to your phone or computer, and if any of these packets are dropped, it will affect the quality of your call. with SIP, when to use TCP not UDP? - Stack Overflow SIP over TCP has a significant advantage over UDP for mobile devices. The reason is due to the use of NAT, and how NAT table entries in a wireless router or a cell providers' router are generally timed out much quicker for UDP vs TCP. SIP Port udp or tcp - Cisco Community

Apr 29, 2014

Guaranteed communication over TCP port 5061 is the main difference between TCP and UDP. UDP port 5061 would not have guaranteed communication as TCP. UDP on port 5061 provides an unreliable service and datagrams may arrive duplicated, out of order, or missing without notice.

Port 5061 (tcp/udp) - Online TCP UDP port finder

Ports Used by 3CX Phone System - A complete list