3Com Switch 7750 Configuration Guide

IS-IS Basic Configuration 337
Configuring Route
Leaking
Through route leaking, a Level-2 router can send the Level-1 area routing
information and Level-2 area routing information that it knows to a Level-1 router.
Configuring Route
Summarization
You can configure the routes having the same IP prefix as one summarized route.
Configuring Default
Route Generation
In an IS-IS routing domain, a Level-1 router maintains the LSDB for the local area
only and generates the routes within the local area only. A Level-2 router
maintains the LSDB for the backbone within the IS-IS routing domain and
generates the routes for the backbone only. To transfer packets to another area, a
Level-1 router in an area needs to first transfer the packets to the nearest Level-1-2
router within the local area. This requires the default route at Level-1.
Configuring Protocol
Priority
For a router running multiple routing protocols, routing information needs to be
shared and selected by the routing protocols. The system assigns a priority for
each routing protocol. When multiple routing protocols discover a route to the
same destination, the protocol with the highest priority will dominate.
Table 261 Configure route leaking
Operation Command Description
Enter system view system-view -
Enter IS-IS view isis [ tag ] Required
Enable route leaking import-route isis level-2 into
level-1 [ acl acl-number ]
Optional
By default, a Level-2 router sends
no routing information to a Level-1
area.
Table 262 Configure route summarization
Operation Command Description
Enter system view system-view -
Enter IS-IS view isis [ tag ] Required
Configure route
summarization
summary ip-address ip-mask
[ level-1 | level-1-2 | level-2 ]
Optional
By default, the system performs no
route summarization.
Table 263 Configure default route generation
Operation Command Description
Enter system view system-view -
Enter IS-IS view isis [ tag ] Required
Configure default route
generation
default-route-advertise
[ route-policy
route-policy-name ]
Optional
The default route is advertised to
only the routers at the same level.
Table 264 Configure protocol priority
Operation Command Description
Enter system view system-view -
Enter IS-IS view isis [ tag ] Required