In the central networking mode of the converged conference MCU, what is correct about the traversal of public and private networks? () (Multiple selected)
A . TE/RP/TP access MCU through SC proxy signaling and media stream
B . eSpace Mobile accesses MCU C through SBC proxy audio and video media.
C . External web client access MCU through MS proxy audio and video
D . eSpace PC connects to MCU through SC proxy signaling and media stream
Answer: A,B,C