I intend to follow my diagram because when setting connect both client and SIP server by IP local, I test make SIP video call does not have freeze frame. I tried to connect to wss of SIP server Asterisk to make SIP video call, it work betters.
The opposite setup connects both client and SIP server by IP public it has often freeze frame.
I tried to change to TCP transport, setting webrtc_cc_max_bitrate, constraints.video.maxBitrate is lower than the default it still suffers.
Below is bandwidth testing with the client:
Bandwitdth with SIP server: