User`s guide

6-1

8000-A2-GB21-10

June 1997

IP Routing

Overview

This chapter presents information regarding the theory behind the configuration

of static routes on the HotWire DSLAM, as well as examples. Both standard

destination-based routes as well as source-based routes are described.

Static Routes

The

routing table stores information about possible destinations for packets

being routed through the HotWire DSLAM and identifies the next hop address to

which to send the packet. A static route is a permanent entry into the routing

table that is manually entered. Although the HotWire DSLAM routing table

supports both destination-based routing and source-based routing, this section

discusses destination-based routing only. (Source-based routing is discussed

later in this chapter.)

The routing table is comprised of:

 Configured static routes

 Routes learned by implication of directly connected hosts/networks

 Routes learned by the MCC card from the DSL about its directly connected

hosts (RTUs)

With destination-based routing, the destination address of the packet being sent

is compared to the destination address entries in the routing table. The

destination address could possibly match one or more of three types of

addresses in the routing table. It could match a:

 Host route address (that is, a specific destination IP address) e.g., 135.1.3.5,

 Subnet route, e.g., 135.1.3.0, or

 Network route, e.g., 135.1.0.0