3Com Switch 8800 Advanced Software V5 Configuration Guide

26
STATIC ROUTING CONFIGURATION
When configuring a static route, go to the following sections for information you
are interested in:
■ “Introduction” on page 259
■ “Configuring a Static Route” on page 260
■ “Displaying and Maintaining Static Routes” on page 262
■ “Configuration Example” on page 262
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The term "router" in this document refers to a router in a generic sense or an
Ethernet switch running routing protocols.
Introduction
Static Route A static route is a special route that is manually configured by the network
administrator. If a network’s topology is simple, you only need configure static
routes for the network to work normally. The proper configuration and usage of
static routes can improve a network’s performance and ensure bandwidth for
important network applications.
The disadvantage of using a static route is that, if a fault or a topological change
occurs to the network, the routes will be unavailable and the network breaks. In
this case, the network administrator has to modify the static routes manually.
Default Route A router selects the default route only when it cannot find any matching entry in
the routing table.
If the destination address of a packet fails to match any entry in the routing table,
the router selects the default route to forward the packet.
If there is no default route and the destination address of the packet fails to match
any entry in the routing table, the packet will be discarded and an ICMP packet
will be sent to the source to report that the destination or the network is
unreachable.
You can create the default route with both destination and mask being 0.0.0.0,
and some dynamic routing protocols, such as OSPF, RIP and IS-IS, can also
generate the default route.