Garmin HM210DP/DI manual Configuring IP Routes, Overview of IP Routes

Configuring IP Routes

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.

6.1Overview 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

38 EN/LZT 108 6492 R2 - October 2003