Assume endpoints T1 and T2 are registered with the same SC node zone.

Inthis process, the H.225 RAS signalinginteraction between T1 and T2 must pass through the SC.

In this process, the H.225 call signaling interaction between T1 and T2 must pass through the SC.

In this process, the media stream must be directly transmitted between T1 and T2.

Endpoint control signaling involved in this process mainly includes H.225 RAS, H.225 Call Signaling, and H.245.