H3C XE 200 IP, Руководство по эксплуатации

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Operation Manual – Process Server Configuration
H3C XE 200/2000 IP PBX
Chapter 2 H.323 Overview
2-3
set up in direct call mode, the H.245 media channel control signaling channel is
established between the calling gateway and the called gateway. Whereas if the call is
set up in routed call mode, the H.245 media channel control signaling channel is
established between the gateway and the gatekeeper.
An H.245 media control signaling channel is independent of the RAS channel and the
H.225.0 call control signaling channel. It is a reliable channel.
V. H.323 call modes
For networks containing gatekeepers, the H.323 call mode refers to the way to transmit
call control signaling and H.245 media channel control signaling. H.323 protocol suite
defines two call modes: direct call and routed call.
z
Direct call
XE IP PBX
(Gatekeeper)
H.323 Gateway
H.323 Gateway
RAS Signal RAS Signal
H.225.0 Signal
H.245 Signal
Figure 2-1 H.323 direct call
The process of a direct call is as follows.
1) The calling gateway gets authenticated at the gatekeeper through RAS signaling
exchange. It then obtains the call signaling address of the called gateway from the
gatekeeper if it passes the authentication.
2) The calling gateway establishes a call control channel between itself and the
called gateway using the call signaling address. Through this channel, the calling
gateway communicates with the called gateway with call control signaling to
exchange H.245 address information.
3) The calling gateway and the called gateway establish media control channel using
the H.245 address information they obtain to exchange multimedia channel
information.
In direct call mode, call control signaling and media channel control signaling are
exchanged between the calling gateway and the called gateway directly rather than
through the gatekeeper.
z
Routed call