Calling Through A Network Router - Polycom V500 Administrator's Manual

Administrator's Guide for the V500 System

Calling Through a Network Router

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Network routers let you connect more than one computer, video conferencing
system, or other device to your cable modem or DSL modem so that they all
can share the same high-speed network connection. This is accomplished by
using Network Address Translation (NAT) services. Routers also often offer
firewall protection.
In a typical IP network, each device within the network has its own unique IP
address, which is available for everyone in or outside the network to access.
With a NAT, each device within the network retains its own IP address, but
the NAT presents a single IP address to the outside world. This provides an
extra level of security because devices inside the network are masked behind
that single, external IP address.
A firewall acts as a security barrier between one network and another. For
example, you might set up a firewall between the network at your home or
business and the Internet. The firewall prevents unsolicited external network
traffic from accessing your internal network.
Because NATs and firewalls provide security for your network, they limit
outside access to your internal network. Some access, however, is necessary
for video communications. To enable your V500 system to place and receive
calls with the outside world, while still maintaining protection for your
network, you must open ports in the firewall. This is called port forwarding or
pinholing.
The following sections describe the steps you need to take to place video calls
through a network router, including:
• Configuring router port forwarding
• Configuring firewall and NAT properties on the V500 system