Information Technology Reference
In-Depth Information
As shown in Figure 14-21, for three gateways the number of logical connections is only
three but grows to ten connections when there are only five gateways. With a gatekeeper,
each gateway contains a simpler dial plan and connects only to the gatekeeper.
V
V
V
V
V
V
3 Gateways
3 Logical Connections
V
V
5 Gateways
10 Logical Connections
V
Gatekeeper
V
V
V
V
V
5 Gateways
5 Logical Connections to GK
Figure 14-21
A Gatekeeper Reduces the Number of Logical Gateway Connections
H.323 terminals must support the following standards:
H.245 call capability control
■
Q.931 c all setup sig naling
■
H.225 call signaling
■
RTP/RTCP voice streams
■
H.245 specifies messages for opening and closing channels for media streams and other
commands, requests, and indications. It is a control channel protocol.
Q.931 is a standard for c all sig naling used by H.323 w ithin the contex t of H.225. It is also
used by PRI links.
