- Configuring OSPF
- IPv6 Routing: OSPFv3
- IPv6 Routing: OSPFv3 Authentication Support with IPsec
- OSPFv2 Cryptographic Authentication
- OSPFv3 IPSec ESP Encryption and Authentication
- OSPF ABR Type 3 LSA Filtering
- OSPF Stub Router Advertisement
- OSPF Update Packet-Pacing Configurable Timers
- OSPF Sham-Link Support for MPLS VPN
- OSPF Retransmissions Limit
- OSPF Support for Multi-VRF on CE Routers
- OSPFv2 Multiarea Adjacency
- OSPFv2 Autoroute Exclude
- OSPFv3 Multiarea Adjacency
- OSPFv3 Authentication Trailer
- OSPFv3 Autoroute Exclude
- OSPFv2-OSPF Live-Live
- OSPFv3 Address Families
- OSPF Forwarding Address Suppression in Translated Type-5 LSAs
- OSPF Inbound Filtering Using Route Maps with a Distribute List
- OSPFv3 Fast Convergence: LSA and SPF Throttling
- OSPF Shortest Path First Throttling
- OSPF Support for Fast Hello Packets
- OSPF Incremental SPF
- OSPF Limit on Number of Redistributed Routes
- OSPFv3 Max-Metric Router LSA
- OSPF Link-State Advertisement Throttling
- OSPF Support for Unlimited Software VRFs per PE Router
- OSPF Area Transit Capability
- OSPF Per-Interface Link-Local Signaling
- OSPF Link-State Database Overload Protection
- OSPF Enhanced Traffic Statistics for OSPFv2 and OSPFv3
- OSPF MIB Support of RFC 1850 and Latest Extensions
- SNMP ifIndex Value for Interface ID in OSPFv2 and OSPFv3 Data Fields
- OSPFv3 Graceful Restart
- OSPF RFC 3623 Graceful Restart Helper Mode
- OSPF Mechanism to Exclude Connected IP Prefixes from LSA Advertisements
- OSPFv2 Local RIB
- OSPFv3 MIB
- TTL Security Support for OSPFv3 on IPv6
- OSPFv3 VRF-Lite/PE-CE
- Graceful Shutdown Support for OSPFv3
- Prefix Suppression Support for OSPFv3
- OSPFv3 ABR Type 3 LSA Filtering
OSPF ABR Type 3 LSA Filtering
The OSPF ABR Type 3 LSA Filtering feature extends the ability of an ABR that is running the OSPF protocol to filter type 3 link-state advertisements (LSAs) that are sent between different OSPF areas. This feature allows only packets with specified prefixes to be sent from one area to another area and restricts all packets with 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.
- Finding Feature Information
- Benefits
- Restrictions
- Configuration Tasks
- Configuration Examples
- Additional References
- Feature Information for the OSPF ABR Type 3 LSA Filtering
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Benefits
The OSPF ABR Type 3 LSA Filtering feature gives the administrator improved control of route distribution between OSPF areas.
Restrictions
Only type 3 LSAs that originate from an ABR are filtered.
Related Features and Technologies
This feature is an extension of the OSPF routing protocol. For more information about configuring OSPF and configuring route summarization and filtering, refer to the "OSPF" module of the Cisco IOS IP Configuration Guide, Release 12.4 and the Cisco IOS IP Routing Protocols Command Reference, Release 12.4T.
Configuration Tasks
See the following sections for configuration tasks for the OSPF ABR Type 3 LSA Filtering feature. Each task in the list is identified as either required or optional:
- Configuring OSPF ABR Type 3 LSA Filtering
- Configuring OSPF ABR Type 3 LSA Filtering
- Verifying OSPF ABR Type 3 LSA Filtering
- Monitoring and Maintaining OSPF ABR Type 3 LSA Filtering
Configuring OSPF ABR Type 3 LSA Filtering
1. Router(config)# router ospf process-id
2. Router(config-router)# area area-id filter-list prefix prefix-list-name in
3. Router(config-router)# exit
4. Router(config)# ip prefix-list list-name [seq seq-value] deny | permit network/len [ge ge-value] [le le-value]
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 | Router(config)# router ospf process-id |
Configures the router to run an OSPF process. |
Step 2 | Router(config-router)# area area-id filter-list prefix prefix-list-name in |
Configures the router to filter interarea routes into the specified area. |
Step 3 | Router(config-router)# exit |
Exits router configuration mode and returns to global configuration mode. |
Step 4 | Router(config)# ip prefix-list list-name [seq seq-value] deny | permit network/len [ge ge-value] [le le-value] |
Creates a prefix list with the name specified for the list-name argument. |
Configuring OSPF ABR Type 3 LSA Filtering
To filter interarea routes out of a specified area, use the following commands beginning in router configuration mode:
1. Router(config)# router ospf process-id
2. Router(config-router)# area area-id filter-list prefix prefix-list-name out
3. Router(config-router)# exit
4. Router(config)# ip prefix-list list-name [seq seq-value] deny | permit network/len [ge ge-value] [le le-value]
DETAILED STEPS
Command or Action | Purpose | |
---|---|---|
Step 1 | Router(config)# router ospf process-id |
Configures the router to run an OSPF process. |
Step 2 | Router(config-router)# area area-id filter-list prefix prefix-list-name out |
Configures the router to filter interarea routes out of the specified area. |
Step 3 | Router(config-router)# exit |
Exits router configuration mode and returns to global configuration mode. |
Step 4 | Router(config)# ip prefix-list list-name [seq seq-value] deny | permit network/len [ge ge-value] [le le-value] |
Creates a prefix list with the name specified for the list-name argument. |
Verifying OSPF ABR Type 3 LSA Filtering
To verify that the OSPF ABR Type 3 LSA Filtering feature has been configured, use the show ip ospf command in the EXEC mode. The show ip ospf command will show that this feature has been enabled by listing the area filter as "in" or "out." The following is sample output from the show ip ospf command:
router# show ip ospf 1 Routing Process "ospf 1" with ID 172.16.0.1 Supports only single TOS(TOS0) routes Supports opaque LSA It is an area border router SPF schedule delay 5 secs, Hold time between two SPFs 10 secs Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs Number of external LSA 0. Checksum Sum 0x0 Number of opaque AS LSA 0. Checksum Sum 0x0 Number of DCbitless external and opaque AS LSA 0 Number of DoNotAge external and opaque AS LSA 0 Number of areas in this router is 2. 2 normal 0 stub 0 nssa External flood list length 0 Area BACKBONE(0) Number of interfaces in this area is 2 Area has no authentication SPF algorithm executed 6 times Area ranges are 10.0.0.0/8 Passive Advertise Area-filter AREA_0_IN in Area-filter AREA_0_OUT out Number of LSA 5. Checksum Sum 0x29450 Number of opaque link LSA 0. Checksum Sum 0x0 Number of DCbitless LSA 0 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0 Area 1 Number of interfaces in this area is 1 Area has no authentication SPF algorithm executed 4 times Area ranges are Area-filter AREA_1_IN in Area-filter AREA_1_OUT out Number of LSA 6. Checksum Sum 0x30100 Number of opaque link LSA 0. Checksum Sum 0x0 Number of DCbitless LSA 0 Number of indication LSA 0 Number of DoNotAge LSA 0 Flood list length 0
Monitoring and Maintaining OSPF ABR Type 3 LSA Filtering
Command |
Purpose |
---|---|
Router# show ip prefix-list
|
Displays information about a prefix list or prefix list entries. |
Configuration Examples
The following configuration example output shows interarea filtering that is applied to both incoming and outgoing routes:
Router(config)# router ospf 1 log-adjacency-changes area 1 filter-list prefix AREA_1_OUT out area 3 filter-list prefix AREA_3_IN in network 10.0.0.0 0.255.255.255 area 3 network 172.16.1.0 0.0.0.255 area 0 network 192.168.0.0 0.255.255.255 area 1 ! ip prefix-list AREA_1_OUT seq 10 permit 10.25.0.0/8 ge 16 ip prefix-list AREA_1_OUT seq 20 permit 172.20.20.0/24 ! ip prefix-list AREA_3_IN seq 10 permit 172.31.0.0/16 !
Additional References
The following sections provide references related to OSPF ABR Type 3 LSA Filtering.
Related Documents
Related Topic |
Document Title |
---|---|
Configuring OSPF ABR Type 3 LSA Filtering |
Configuring OSPF ABR Type 3 LSA Filtering |
OSPF commands: complete command syntax, command mode, command history, command defaults, usage guidelines, and examples |
Cisco IOS IP Routing: OSPF Command Reference |
Standards
Standard |
Title |
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None |
-- |
MIBs
MIB |
MIBs Link |
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None |
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL: |
RFCs
RFC |
Title |
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None |
-- |
Technical Assistance
Description |
Link |
---|---|
The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
Feature Information for the OSPF ABR Type 3 LSA Filtering
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to . An account on Cisco.com is not required.
Feature Name |
Releases |
Feature Informatoin |
---|---|---|
OSPF ABR Type 3 LSA Filtering |
12.2(4)T |
This feature was integrated into Cisco IOS Release 12.2(4)T. |
OSPF ABR Type 3 LSA Filtering |
12.2(4)T3 |
Support for the Cisco 7500 series was added in Cisco IOS Release 12.2(4)T3. |
OSPF ABR Type 3 LSA Filtering |
12.2(8)T |
Support for the Cisco 1710, 1721, 3631, 3725, 3745 and IGX 8400 series URM was added in Cisco IOS Release 12.2(8)T. |
OSPF ABR Type 3 LSA Filtering |
12.2(11)T |
Support for the Cisco AS5300, AS5400, and AS5800 series was integrated into Cisco IOS Release 12.2(11)T. |