SMC Networks SMC6724L3 manual 196, 271

summary

route

CONFIGURING THE SWITCH

Console#show ip ospf		4-271
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#

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	area ABR area

these nodes, this wastes a lot of bandwidth and processor time. Instead, you can

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.

Command Usage

•Use the Area Range Configuration page to summarize the routes for an area. The summary route for an area is defined by an IP address and network mask. You therefore need to structure each area with a contiguous set of addresses so that all routes in the area fall within an easily specified range. This router also supports Variable Length Subnet Masks (VLSMs), so you can summarize an address range on any bit boundary in a network address.

•To summarize the external LSAs imported into your autonomous system (i.e., local routing domain), use the Summary Address Configuration screen (page 3-208).

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