Optimizing Call Routing On The H.323 Network - RADVision L2W-323 User Manual

Distance between Neighbor Gatekeepers
You can define a distance between zones in a network to give you more management
control over endpoint calling privileges and restrictions. The distance is a logical range
assigned between zones in the network. The distance between zones is defined by the
Neighbor Distance parameter. This parameter works together with the Max. Distance
parameter of a predefined endpoint and Default Distance of a dynamically registered
endpoint.
When you define predefined properties for an endpoint with the Gatekeeper, you can assign
it a Max. Distance value. This value is any number from 0 to 255 and represents a logical
distance that means, "this is the distance a call can travel for this endpoint." The Default
Distance is the Max. Distance for dynamically registered endpoints.
When an endpoint for which you have defined the Max. Distance or the Default Distance
parameter requests to make a call to an endpoint in another zone, the Gatekeeper compares
the Max. Distance (or the Default Distance) parameter to the Neighbor Distance parameter.
The call is completed if the Max. Distance or Default Distance of the endpoint is equal to or
larger than the Neighbor Distance parameter.
Note: To avoid distance limitations across the network you can set all distance parameters
to 0.

Optimizing Call Routing on the H.323 Network

You can divide the network into islands allowing the Gatekeeper to direct calls through
optimal routes and to avoid slow network connections or bottlenecks caused by routers. An
island is a cluster of 'subnets' characterized by homogenous and fast videoconferencing
LAN connectivity. Islands are LAN portions connected to other LAN portions via routers.
The use of the term 'subnet' helps define islands but it may be different from the regular
usage of the network term subnets. It is possible to define a single host as a 'subnet' by
using a mask of 255.255.255.255. A 'subnet' in this context is actually an 'island portion.'
Note: The Gatekeeper identifies an island by an island code. All of the 'subnets' that have
been defined with a specific island code belong to that island.
The following figure illustrates service call routing using an island scheme. If you use
islands, the Gatekeeper routes service calls first to the Gateways or terminal that provides
the requested service that belongs to the same island, and only if these are unavailable, to
Gateways or terminals in other islands.
Understanding the Internal Gatekeeper
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