This figure shows the call flow between a client application, the Signaling Engine, and a SIP server. The client application first starts a WebRTC JSON Session/WebSocket connection with the Signaling Engine with a handshake connect and response. It then sends a connect message which causes the Signaling Engine to open an SIP session with the SIP Server.
The messages include:
Client to Signaling Engine: connect
Signaling Engine to SIP Server: REGISTER
SIP Server to Signaling Engine: 200
/OK.
Signaling Engine to Client: connect
/response.
Client to Signaling Engine: start
. This starts a new subsession and corresponding SIP session.
Signaling Engine to SIP Server: INVITE
.
SIP Server to Signaling Engine: 100
/trying and then 200
/ringing.
Signaling Engine to Client: start
/initial response.
SIP Server to Signaling Engine: 200/OK
Signaling Engine to Client: start/final response
.
Client to Signaling Engine: complete
.
Signaling Engine to SIP Server: ACK
.
Then the media sesison happens between the Client and an unpictured entity.
SIP Server to Signaling Engine: BYE
.
SIP Server to Client: BYE
.
Signaling Engine to SIP Server: 200/OK