Bob’s Bicycles recently implemented a H.323 videoconferencing solution, and wishes to conduct videoconferences with the main supplier over the extranet using the existing four-digit numbering plan at each company. Due to overlapping dial plans, the called digits must be manipulated to allow the video calls to be completed. Which solution can support this?

A.
H.323 proxy

B.
gatekeeper

C.
directory gatekeeper

D.
IP-to-IP gateway