1.4 Relationship to Other Protocols
The Microsoft NetMeeting Protocol is implemented on top of the T.120 protocol set, as defined in [T120].
These extensions use the following ports and protocols:
Port 389 Internet Locator Server [Transmission Control Protocol] (TCP/IP)
Port 522 User Location Server (TCP/IP)
Port 1503 T.120 (TCP/IP and TPKT)
Port 1720 H.245/H.225/[ITU-Q.931] call setup (TCP/IP)
Note H.245 uses the default port (1720) for initial call setup, and can use a different (dynamic) port for subsequent communication.
Port 1731 Audio call control (TCP/IP)