Prerequisites for OSPF LSA Throttling
It is presumed that you have OSPF configured in your network.
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The OSPF Link-State Advertisement Throttling feature provides a dynamic mechanism to slow down link-state advertisement (LSA) updates in Open Shortest Path First (OSPF) during times of network instability. It also allows faster OSPF convergence by providing LSA rate limiting in milliseconds.
It is presumed that you have OSPF configured in your network.
Prior to the OSPF LSA Throttling feature, LSA generation was rate-limited for 5 seconds. That meant that changes in an LSA could not be propagated in milliseconds, so the OSPF network could not achieve millisecond convergence.
The OSPF LSA Throttling feature is enabled by default and allows faster OSPF convergence (in milliseconds). This feature can be customized. One command controls the generation (sending) of LSAs, and another command controls the receiving interval. This feature also provides a dynamic mechanism to slow down the frequency of LSA updates in OSPF during times of network instability.
The timers throttle lsa all command controls the generation (sending) of LSAs. The first LSA is always generated immediately upon an OSPF topology change, and the next LSA generated is controlled by the minimum start interval. The subsequent LSAs generated for the same LSA are rate-limited until the maximum interval is reached. The "same LSA" is defined as an LSA instance that contains the same LSA ID number, LSA type, and advertising router ID.
The timers lsa arrival command controls the minimum interval for accepting the same LSA. If an instance of the same LSA arrives sooner than the interval that is set, the LSA is dropped. It is recommended that the arrival interval be less than or equal to the hold-time interval of the timers throttle lsa all command.
Command or Action | Purpose | |
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Step 1 |
enable Example:
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Enables privileged EXEC mode.
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Step 2 |
configure terminal Example:
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Enters global configuration mode. |
Step 3 |
router ospf process-id Example:
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Configures an OSPF routing process. |
Step 4 |
timers throttle lsa all start-interval hold-interval max-interval Example:
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(Optional) Sets the rate-limiting values (in milliseconds) for LSA generation.
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Step 5 |
timers lsa arrival milliseconds Example:
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(Optional) Sets the minimum interval (in milliseconds) between instances of receiving the same LSA.
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Step 6 |
end Example:
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Exits router configuration mode. |
Step 7 |
show ip ospf timers rate-limit Example:
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(Optional) Displays a list of the LSAs in the rate limit queue (about to be generated).
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Step 8 |
show ip ospf Example:
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(Optional) Displays information about OSPF.
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This example customizes OSPF LSA throttling so that the start interval is 200 milliseconds, the hold interval is 10,000 milliseconds, and the maximum interval is 45,000 milliseconds. The minimum interval between instances of receiving the same LSA is 2000 milliseconds.
router ospf 1
log-adjacency-changes
timers throttle lsa all 200 10000 45000
timers lsa arrival 2000
network 10.10.4.0 0.0.0.255 area 24
network 10.10.24.0 0.0.0.255 area 24
The following sections provide references related to OSPF LSA throttling.
Related Topic |
Document Title |
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Cisco IOS commands |
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OSPF commands |
Cisco IOS IP Routing: OSPF Command Reference |
Configuring OSPF |
"Configuring OSPF" |
OSPFv3 Fast Convergence: LSA and SPF Throttling |
“OSPFv3 Fast Convergence: LSA and SPF Throttling” module |
OSPFv3 Max-Metric Router LSA |
“OSPFv3 Max-Metric Router LSA” module |
Standard |
Title |
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None |
-- |
MIB |
MIBs Link |
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No new or modified MIBs are supported by this feature, and support for existing MIBs has not been modified by this feature. |
To locate and download MIBs for selected platforms, Cisco IOS XE releases, and feature sets, use Cisco MIB Locator found at the following URL: |
RFC |
Title |
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None |
-- |
Description |
Link |
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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. |
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 www.cisco.com/go/cfn. An account on Cisco.com is not required.
Feature Name |
Releases |
Feature Information |
---|---|---|
OSPF Link-State Advertisement Throttling |
Cisco IOS XE Release 2.1 Cisco IOS XE Release 2.6 |
The OSPF Link-State Advertisement Throttling feature provides a dynamic mechanism to slow down link-state advertisement (LSA) updates in OSPF during times of network instability. It also allows faster OSPF convergence by providing LSA rate limiting in milliseconds. The following commands are introduced or modified in the feature documented in this module:
|
Feature Name |
Releases |
Feature Information |
---|---|---|
OSPF Link-State Advertisement Throttling |
Cisco IOS XE Release 17.4 |
This feature was introduced. |