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5. Routed Mode and Proxy Configuration

5.1 Section [RoutedMode]

Call signaling messages may be passed in two ways: The first method is Direct Endpoint Call Signaling, in which case the call signaling messages are passed directly between the endpoints. The second method is Gatekeeper Routed Call Signaling. With this method, the call signaling messages are routed through the gatekeeper. The choice of which methods is used is made in the gatekeeper configuration.

When Gatekeeper Routed call signaling is used, the gatekeeper may choose whether to route the H.245 control channel and media channels.

Case I.

The gatekeeper doesn't route them. The H.245 control channel and media channels are established directly between the endpoints.

Case II.

The H.245 control channel is routed through the gatekeeper, while the media channels are established directly between the endpoints.

Case III.

The gatekeeper routes the H.245 control channel, as well as all media channels, including RTP/RTCP for audio and video, and T.120 channel for data. In this case, no traffic is passed directly between the endpoints. This is usually called an H.323 Proxy, which can be regarded as an H.323-H.323 gateway.

This section defines the gatekeeper routed mode options (case I & II). The proxy feature is defined in the next section. All settings in this section are affected by reloading the configuration at runtime.

5.2 Section [Proxy]

The section defines the H.323 proxy features. It means the gatekeeper will route all the traffic between the calling and called endpoints, so there is no traffic between the two endpoints directly. Thus it is very useful if you have some endpoints using private IP behind an NAT box and some endpoints using public IP outside the box.

The gatekeeper can do proxy for logical channels of RTP/RTCP (audio and video) and T.120 (data). Logical channels opened by fast-connect procedures or H.245 tunneling are also supported.

Note to make proxy work, the gatekeeper must have direct connection to both networks of the caller and callee.


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