3com DUA1750-2BAA01 Manual De Usuario

3Com Switch 8800 Configuration Guide 

Chapter 17  Static Route Configuration

 

17-1 

A static route is a special route configured manually by an administrator. You can set up 

an interconnecting network with the static route configuration. The problem for such 

configuration is when a fault occurs to the network, the static route cannot change 

automatically to steer away from the node causing the fault, if without the help of an 

administrator. 

In a relatively simple network, you only need to configure the static routes to make the 

router work normally. The proper configuration and usage of the static route can 

improve the network performance and ensure the bandwidth of the important 

applications.  

All the following routes are static routes: 

z 

Reachable route: A normal route is of this type. That is, the IP packet is sent to the 

next hop via the route marked by the destination. It is a common type of static 

routes. 

z 

Unreachable route: When a static route to a destination has the "reject" attribute, 

all the IP packets to this destination will be discarded, and the source host will be 

informed that the destination is unreachable. 

z 

Blackhole route: If a static route to a destination has the “blackhole” attribute, the 

outgoing interface of this route is the Null 0 interface regardless of the next hop 

address, and any IP packets addressed to this destination are dropped without 

notifying the source host. 

The attributes "reject" and "blackhole" are usually used to control the range of 

reachable destinations of this router, and help troubleshooting the network. 

A default route is a special route. You can configure a default route using a static route. 

Some dynamic routing protocols can also generate default routes, such as OSPF and 

IS-IS. 

In brief, a default route is used only when no suitable routing table entry is matched. 

That is, when no proper route is found, the default route is used. In a routing table, the 

default route is in the form of the route to the network 0.0.0.0 (with the mask 0.0.0.0). 

You can see whether the default route has been set by executing the display ip 

routing-table  command. If the destination address of a packet fails in matching any 

entry of the routing table, the router will select the default route to forward this packet. If