$
1
1
1
1
1
$
1
1
1
1
1
$
1
1
1
1
1
Composite Model
Figure 2 - 1
$
1
1
1
1
1
$
1
1
1
1
1
PSTN
ISDN
Qos
Enabled
IP WAN
Headquarters with one or
more zones, and
local PSTN and MCU
access
Large Branch
With one or more zones,
local PSTN, and MCU
Access
H.323 to H.320
Gateway
Small Branch
With no local gatekeeper,
PSTN or MCU services, all
services will be handled at
Headquarters site
$
1
1
1
1
1
H.320 Endpoints
MCU
H.320 MCU
Gatekeeper
Proxy
Gatekeeper
Proxy
`
Gatekeeper
MCU
Gateway
Video intrastructure
Campus single zone
Figure 2- 2
$
1
1
1
1
1
$
1
1
1
1
1
$
1
1
1
1
1
$
1
1
1
1
1
$
1
1
1
1
1
$
1
1
1
1
1
Campus Backbone
Bidg 2
Gatekeeper
MCU
Gateway
Video intrastructure
Campus single zone
Figure 2- 2
Video intrastructure
Gatekeeper
zone 1
MCU’S
Campus single zone
Figure 2- 2
$
1
1
1
1
1
$
1
1
1
1
1
$
1
1
1
1
1
$
1
1
1
1
1
$
1
1
1
1
1
$
1
1
1
1
1
Campus Backbone
Bidg 2
Gatekeeper
zone 2
Gateway
Campus single zone
Figure 2- 3
P
S
T
N
I
S
D
N
Video intrastructure