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1Cisco IOS Release 12.2(4)T3OSPF Update Packet-Pacing Configurable TimersFeature HistoryThis feature module describes the OSPF Update Packet-Pacing Configurable Timers feature. It includes the following sections:Feature Overview, page 1Benefits, page 2Related Features and Technologies, page 2Supported Platforms, page 2Supported Standards, MIBs, and RFCs, page 3Configuration Tasks, page 4Monitoring and Maintaining OSPF Packet-Pacing Timers, page 6Configuration Examples, page 6Command Reference, page 7Feature OverviewIn rare situations, you might need to change Open Shortest Path First (OSPF) packet-pacing default timers to mitigate CPU or buffer utilization issues associated with flooding very large numbers of link-state advertisements (LSAs). The OSPF Update Packet-Pacing Configurable Timers feature allows you to configure the rate at which OSPF LSA flood pacing, retransmission pacing, and group pacing updates occur.ReleaseModification12.2(4)TThis feature was introduced.12.2(4)T3Support for the Cisco 7500 series was added in Cisco IOS Release 12.2(4)T3.12.2(8)TSupport for the Cisco 1710, 3631, 3725, 3745, and URM was added in Cisco IOS Release 12.2(8)T.12.2(8)T1Support for the Cisco 2691 was added in Cisco IOS Release 12.2(8)T1.OSPF Update Packet-Pacing Configurable Timers Supported Platforms2Cisco IOS Release 12.2(4)T3Configuring OSPF flood pacing timers allows you to control interpacket spacing between consecutive link-state update packets in the OSPF transmission queue. Configuring OSPF retransmission pacing timers allows you to control interpacket spacing between consecutive link-state update packets in the OSPF retransmission queue. Cisco IOS software groups the periodic refresh of LSAs to improve the LSA packing density for the refreshes in large topologies. The group timer controls the interval used for group LSA refreshment; however, this timer does not change the frequency that individual LSAs are refreshed (the default refresh occurs every 30 minutes).NoteThe default settings for OSPF packet pacing timers are suitable for the majority of OSPF deployments. You should change the default timers only as a last resort.BenefitsThe OSPF Update Packet-Pacing Configurable Timers feature provides the administrator with a mechanism to control the rate at which LSA updates occur in order to reduce high CPU or buffer utilization that can occur when an area is flooded with a very large number of LSAs.RestrictionsDo not change the packet pacing timers unless all other options to meet OSPF packet flooding requirements have been exhausted. Specifically, network operators should prefer summarization, stub area usage, queue tuning, and buffer tuning before changing the default timers. Furthermore, there are no guidelines for changing timer values; each OSPF deployment is unique and should be considered on a case-by-case basis. The network operator assumes risks associated with changing the default timer values.Related Features and TechnologiesThe OSPF Update Packet-Pacing Configurable Timers feature is an extension of the OSPF routing protocol. For more information about configuring OSPF, packet pacing, area border router (ABR) and autonomous system boundary router (ASBR) summarization, and stub router configuration, refer to the Release 12.2 Cisco IOS IP Routing Configuration Guide and the Cisco IOS IP Command Reference, Volume 2 of 3: Routing Protocols.Supported PlatformsThe OSPF Update Packet-Pacing Configurable Timers feature is supported by the following platforms in Cisco IOS Release 12.2(4)T that support OSPF:Cisco 1710 (Supported in Release 12.2(8)T and above.)Cisco 2500 seriesCisco 2600 seriesCisco 2691 (Supported in Release 12.2(8)T1 and above.)Cisco 3620Cisco 3631 (Supported in Release 12.2(8)T and above.)OSPF Update Packet-Pacing Configurable Timers Supported Standards, MIBs, and RFCs3Cisco IOS Release 12.2(4)T3Cisco 3640Cisco 3725 (Supported in Release 12.2(8)T and above.)Cisco 3745 (Supported in Release 12.2(8)T and above.)Cisco 7200 seriesCisco 7500 series (Supported in Release 12.2(4)T3 and above.)Universal Router Module (Supported in Release 12.2(8)T and above.)Determining Platform Support Through Feature Navigator Cisco IOS software is packaged in feature sets that support specific platforms. To get updated information regarding platform support for this feature, access Feature Navigator. Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image.To access Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmithcisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is s
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