Polycom VS4000 User Manual

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Integrators’ Reference Manual for ViewStation EX, ViewStation FX, and VS4000
52
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LAN/WAN Considerations
You will need to develop a network topology checklist that includes 
the following information:
List of Networks:
 To take advantage of least cost routing and 
alternate routing, you must define the topology of the Local area 
networks (LANs) that each gatekeeper serves, as well as the 
LANs that are logically connected to these but served by other 
gatekeepers. This allows the gatekeeper to determine how IP 
traffic is routed from one endpoint to the next. PathNavigator 
uses the network topology to determine when resources are 
unavailable so that an alternate (ISDN) path can be determined. 
Subnets within each network and subnet IP address:
 A 
network address is the equivalent of a subnet. You will need to 
define all subnet addresses within your LAN. If this information 
is not available to the gatekeeper, calls may be rejected because 
no route can be determined.
WAN links:
 These are logical connections from one LAN to 
another LAN within the WAN cloud, or logical connections 
from one network to another network outside of the 
organization. The two types of WAN links are the dedicated 
WAN link, which is a logical connection via a dedicated link, 
leased line, frame relay or though an ATM network; and the 
WAN link to other networks through a VPN tunnel, which 
connects one network to another through a secure connection 
over the Internet.
Network Diagram
 describing how networks are connected and 
bandwidth capacity on each WAN link.
Each gatekeeper will need information about its neighbor 
gatekeepers to be able to communicate with them. Neighbor 
gatekeepers manage other H.323 zones within an organization and 
allow the network’s workload to be distributed across logical 
boundaries within the organization. This enables more efficient use 
of the network by limiting communication between zones (across 
WAN links). When a call originates with one gatekeeper's zone and 
that zone's gatekeeper is unable to resolve the dialed address, it will 
be forwarded to the neighbor gatekeepers for resolution. The port 
used for gatekeeper-to-gatekeeper communication is usually 1719.