Cisco Cisco IOS Software Release 12.0(15)S Livre blanc
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Cisco IOS Release 12.0(15)S
ABR Type 3 LSA Filtering
This feature module describes filtering interarea routes on an Area Border Router (ABR) with the Open
Shortest Path First (OSPF) protocol and includes the following sections:
Shortest Path First (OSPF) protocol and includes the following sections:
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Feature
Overview
The ABR Type 3 link-state advertisement (LSA) Filtering feature extends the capability of an ABR that
is running the OSPF protocol to filter type 3 LSAs between different OSPF areas. This feature allows
only specified prefixes to be sent from one area to another area and restricts all other prefixes. This type
of area filtering can be applied out of a specific OSPF area, into a specific OSPF area, or into and out
of the same OSPF areas at the same time. This feature is supported by the addition of the area filter-list
command.
is running the OSPF protocol to filter type 3 LSAs between different OSPF areas. This feature allows
only specified prefixes to be sent from one area to another area and restricts all other prefixes. This type
of area filtering can be applied out of a specific OSPF area, into a specific OSPF area, or into and out
of the same OSPF areas at the same time. This feature is supported by the addition of the area filter-list
command.
Benefits
The OSPF ABR Type 3 LSA Filtering feature gives the user improved control of route distribution
between OSPF areas.
between OSPF areas.
Restrictions
Only type-3 LSAs that originate from an ABR are filtered.