Garmin HM210DP/DI - Manual (Page 46)

Configuring IP Routes
38 EN/LZT 108 6492 R2 - October 2003
6 Configuring IP Routes
You can use the Configuration Manager to define specific routes for your
Internet and network data. This chapter provides instructions for creating
routes.
Most users do not need to define IP routes. On a typical small home or
office LAN, the existing routes that set up the default gateways for your
LAN computers and for the HM210dp/di provide the most appropriate path
for all your Internet traffic. You may need to define routes if:
Your network setup includes two or more networks or subnets.
You connect to two or more ISP services.
You connect to a remote corporate LAN.
6.1 Overview of IP Routes
The essential challenge of a router is: when it receives data intended for a
particular destination, which next device should it send that data to? When
you define IP routes, you provide the rules that a computer uses to make
these decisions.
Each time Internet data is passed from one Internet address to another, it is
said to take a hop. A hop can be a handoff to a different port on the same
device, to a different device on the same network, or to a device on an
entirely different network.
When a hop passes data from one type of network to another, it uses a
gateway. A gateway is an IP address that provides initial access to a
network, just as a switchboard serves as a gateway to a specific set of
phone numbers. For example, when a computer on your LAN requests
access to a company’s web site, your ISP serves as a gateway to the
Internet. As your request reaches its destination, another gateway provides
access to the company’s web servers.
IP routes are defined on computers, routers, and other IP-enabled devices
to instruct them which hop to take, or which gateway to use, to help forward
data along to its specified destination.
If no IP route is defined for a destination, then IP data is passed to a
predetermined default gateway. The default gateway serves like a higher-
level telephone switchboard; it may not be able to connect directly to the
destination, but it will know a set of other devices that can help pass the