1-2 
Figure 1-1 A sample routing table 
Switch A
Switch B
Switch H
Switch E
16.0.0.2
17.0.0.3
15.0.0.0
12.0.0.0
17.0.0.0
11.0.0.016.0.0.0
13.0.0.0
14.0.0.0
Switch C
Switch D
Switch F
Switch G
11.0.0.1
12.0.0.1
12.0.0.2
15.0.0.1
15.0.0.2
17.0.0.1
16.0.0.1
13.0.0.1
13.0.0.2
14.0.0.1
14.0.0.2
14.0.0.3
14.0.0.4
17.0.0.2
11.0.0.2
13.0.0.3
 
Destination Network  Nexthop  Interface 
11.0.0.0 11.0.0.1 2 
12.0.0.0 12.0.0.1 1 
13.0.0.0 12.0.0.2 1 
14.0.0.0 14.0.0.4 3 
15.0.0.0 14.0.0.2 3 
16.0.0.0 14.0.0.2 3 
17.0.0.0 11.0.0.2 2 
 
Static Route 
A static route is a manually configured. If a network’s topology is simple, you only need to configure 
static routes for the network to work normally. The proper configuration and usage of static routes can 
improve network performance and ensure bandwidth for important network applications.  
The disadvantage of using static routes is that they cannot adapt to network topology changes. If a fault 
or a topological change occurs in the network, the routes will be unreachable and the network breaks. In 
this case, the network administrator has to modify the static routes manually.  
Default Route 
If the destination address of a packet fails to match any entry in the routing table, the packet will be 
discarded. 
After a default route is configured on a switch, any packet whose destination IP address matches no 
entry in the routing table can be forwarded to a designated upstream switch.  
A switch selects the default route only when it cannot find any matching entry in the routing table. 
z  If the destination address of a packet fails to match any entry in the routing table, the switch selects 
the default route to forward the packet.