3com 3800 ユーザーズマニュアル

Dynamic routes are typically learned by way of RIP. Routers using RIP 
exchange information in their routing tables in the form of RIP 
advertisements. Using dynamic routes, the routing table contains only 
networks that are reachable. 

Dynamic routes are aged out of the table when a RIP update for the 
network is not received for a period of time. 

Static routes are manually entered into the routing table. Static routes 
are used to reach networks not advertised by routers. You can 
configure up to 64 static unicast routes on the Switch 3800. 

Static routes can also be used for security reasons, to control which 
routes you want advertised by the router. You can decide if you want 
all static routes to be advertised by using the following command:

[enable | disable] rip exportstatic

The default setting is enabled. Static routes are never aged out of the 
routing table.

When there are multiple, conflicting choices of a route to a particular 
destination, the router picks the route with the longest matching 
network mask. If these are still equal, the router picks the route using 
the following criteria (in the order specified):

■

Directly attached network interfaces

■

ICMP redirects (refer to Table 8-4)

■

Static routes

■

RIP

■

Directly attached network interfaces that are not active.

You can also configure blackhole routes—traffic to these destinations 
is silently dropped.

SW3800.BK  Page 3  Tuesday, May 5, 1998  5:20 PM