3Com Switch 8800 Configuration Guide Chapter 20 Integrated IS-IS Configuration
20-14
By default, the system disables route summarization.
20.2.11 Setting to Generate Default Route In the IS-IS route domain, the Level-1 router only has the LSDB of the local area, so it
can only generate the routes in the local areas. But the Level-2 router has the
backbone LSDB in the IS-IS route domains and generates the backbone network
routes only. If a Level-1 router in one area wants to forward the packets to other areas,
it needs to first forward the packets to the closest Level-1-2 router in the local area
along its default route. You do not need to configure the default Level-1 route, but need
to manually configure the default Level-2 route.
Perform the following configurations in IS-IS view.
Table 20-12 Set to generate default route
Operation Command
Set to generate default route default-route-advertise [ route-policy
route-policy-name ]
Set not to generate default route undo default-route-advertise
[ route-policy route-policy-name ]
The default route generated by this command will only be imported to the router at the
same level.
20.2.12 Setting the Preference of IS-IS Protocol In a router on which several routing protocols are concurrently operating, there is an
issue of sharing and selecting the routing information among all the routing protocols.
The system sets a preference for each routing protocol. When various routing protocols
find the route to the same destination, the protocol with the higher preference will take
effect.
Perform the following configuration in IS-IS view.
Table 20-13 Configure the preference of IS-IS protocol
Operation Command
Configure the preference of IS-IS protocol preference value
Restore the default preference of IS-IS protocol undo preference
By default, the preference of IS-IS route is 15.