Multiple Zones with Multiple Gatekeepers
Headquarters
Campus
Large
Site
Zone Seattle
T-1
384 K Frame Relay 256 K Frame Relay
Indianapolis Columbus
Zone Chicago
Zone
Indianapolis
128 K
Frame
Relay
256 K
Frame
Relay
Salt Lake City Phoenix
Zone
Salt Lake City
Zone
Columbus
Small offices, such as sales offices do not need their own gatekeepers.
Especially if there are a large number of small offices, assigning each their own
gatekeeper becomes unmanageable and expensive. Instead small offices can be
placed into their own zones, but can utilize a remote gatekeeper.The gatekeeper
at the major site can manage the zone at that site and zones for all smaller sites
that connect to that site.The gatekeeper limits the amount of bandwidth used by
calls into or out of each zone.
As shown in Figure 5.4, the Seattle gatekeeper can manage the Seattle, Salt
Lake City, and Phoenix zones. Placing each site in its own zone allows each site
(zone) to set its own limit on voice and video traffic.This is important since different
sites will have different size WAN connections as well as different traffic
patterns.
Chicago is a large enough site to warrant its own gatekeeper.The Chicago
gatekeeper can manage the Chicago, Indianapolis, and Columbus zones. It will
control how many voice and video calls are placed to and from Chicago, to and
from Indianapolis, and to and from Columbus.
If a call is placed from Phoenix to Columbus, the Seattle gatekeeper determines
whether the Phoenix endpoint can place the call.The Chicago gatekeeper,
meanwhile, determines whether the Columbus endpoint can receive it.