The SIP task extensions support SIP (Session Initiation Protocol), as defined by IETF. The tasks supports sending/receiving of SIP messages as described in the protocol support page.
Transport protocols supported are TCP, UDP and TLS.
The SIP tasks are typically used to simulate a User Agent Server (UAS) or User Agent Client (UAC), but in later versions other kind of nodes can also be simulated (by using Shared SIP Stack support).
Installation, Loading and Using Custom Tasks
SIP Tasks Reference