The H.323 Signaling Group (H323-SGR) MO supports a signaling channel (D-Channel) for H.323 Trunk connections. The G4xx Media Gateways and Avaya Aura® Media Server provides audio connectivity, working in concert with a PROCR that provides control signaling to support an H.323 connection.

H323-SGR is a signaling channel that physically resides on a PROCR port (socket) and the IP network. Unlike ISDN D-channels, the H.323 channel may actually come up and down on a call by call basis. The H.323 channel is actually a TCP/IP signaling channel. Layers 1 and 2 of this signaling channel are monitored by IP PING testing.