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Area range – Enterasys Networks X-Pedition XSR CLI User Manual

Page 162

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OSPF Commands

5-86 Configuring the Internet Protocol

Default

No NSSA defined

Example

The following example configures area 10 as a NSSA area:

XSR(config)#interface fastethernet 1
XSR(config-if)#ip address 172.16.10.5 255.255.255.252
XSR(config)#router ospf 1
XSR(config-router)#network 172.16.10.5 0.0.0.0 area 10
XSR(config-router)#area 10 nssa default-information-originate

area range

This command defines the range of addresses to be used by Area Boundary Routers (ABRs) when 
they communicate routes to other areas. ABRs summarize an area’s intra‐area routes into inter
area routes which are then injected into other areas. The metric used is the highest metric of the 
included intra‐area routes. The forwarding address is 0.

Other actions implemented by this command include:

A summary range becomes active if it includes at least one intra‐area route being leaked into 
the area.

A discard route is installed for an active summary range. Conversely, when it becomes 
inactive, the discard route is removed.

The cost of the summary range is the highest cost among all leaked intra‐area routes.

SNMP supports area range via MIB object ospfAreaRangeTable as defined in RFC‐1850.

Syntax

area area-id range ip-address mask [advertise][not-advertise]

Syntax of the “no” Form

The no form of this command bars routes from being summarized:

no area area-id range address mask

Note: You should avoid needless reorigination of Type-3 Link-State Advertisements (LSAs). For
example, leaking intra-area routes which do not change the cost of a summary will re-origination the
summary LSA.

area-id

Area at the boundary of which routes will be summarized. Valid values 
are decimals or IP addresses.

ip-address

Common prefix of summarized networks.

mask

Length of the common prefix.

advertise

Broadcasts a single Type‐3 LSA for all intra‐area routes leaked into this 
area and included in the summary range.

not

-

advertise

Suppresses Type‐3 LSA generation for all routes in the summary range.