International Network Hardware User Manual

9-2 Introduction to Routing
Introduction to Routing
This section provides some introductory information on routing.
What is Routing
Routing is the method, employed by IP software, of choosing a path over which to send packets
between systems on different physical networks. When Digi One/PortServer TS 2/4 is configured as
a router, it performs this service.
Types of Routing
Digi One/PortServer TS 2/4 can be configured to perform the following types of routing:
• Static routing. When you use static routing, you manually configure routes to other networks for
Digi One/PortServer TS 2/4. Static routing works fine for small, stable networks. Maintaining
static routes is difficult on larger networks and on networks that experience a lot of changes.
• Dynamic routing. When you use dynamic routing, routes are not manually configured but are
automatically established and maintained using information provided by routing information
protocol (RIP). Route maintenance is obviously easier using RIP, but RIP has some shortcom-
ings that are discussed later in this chapter. Digi One/PortServer TS 2/4 supports the RIP 1 stan-
dard.
• Proxy ARP, which is a technique in which a router answers ARP requests intended for another
system. Typically, you use proxy ARP to move packets between physical networks that use the
same IP network address. By pretending to be the other system, the Digi One/PortServer TS 2/4
accepts responsibility for forwarding packets to that system. Proxy ARP makes routing decisions
based on either static routes or on routing information provided by RIP.