Configuring the ECN330-switch
446 1553-KDU 137 365 Uen D 2006-06-16
CLI - This example configures area 0.0.0.1 as a normal area, area 0.0.0.2 as a
stub, and area 0.0.0.3 as an NSSA. It also configures the router to propagate a
default summary route into the stub and sets the cost for this default route to 10.
6.20.10.3 Configuring Area Ranges (Route Summarization for ABRs)
An OSPF area can include a large number of nodes. If the Area Border Router
(ABR) has to advertise route information for each of these nodes, this wastes a
lot of bandwidth and processor time. Instead, configure an ABR to advertise a
single summary route that covers all the individual networks within its area.
When using route summaries, local changes do not have to be propagated to
other area routers. This allows OSPF to be easily scaled for larger networks, and
provides a more stable network topology.
Figure 200 Route Summarization for ABRs
Console(config-router)#network 10.1.1.0 255.255.255.0
area 0.0.0.1
Console(config-router)#area 0.0.0.2 stub summary
Console(config-router)#area 0.0.0.2 default-cost 10
Console(config-router)#area 0.0.0.3 nssa
Console(config-router)#end
Console#show ip ospf
Routing Process with ID 192.168.1.253
Supports only single TOS(TOS0) route
Number of area in this router is 3
Area 0.0.0.0 (BACKBONE)
Number of interfaces in this area is 1
SPF algorithm executed 40 times
Area 0.0.0.2 (STUB)
Number of interfaces in this area is 1
SPF algorithm executed 8 times
Area 0.0.0.3 (NSSA)
Number of interfaces in this area is 1
SPF algorithm executed 40 times
Console#
areaarea
ABR
summary
route
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