Lab 24: OSPF Multiple Area Routing, Authentication, Path Manipulation, Default Routing-Part I

Tuning OSPF

OSPF has several parameters for tuning timers, controlling broadcasts, and controlling routes and link-state propagation. The following list shows the syntax of the more common parameters adjustable for OSPF, explained in the text that follows .

 Router(config-if)  ip ospf hello-interval   interval_in_seconds  Router(config-if)  ip ospf dead-interval   dead_interval_in_seconds  Router(config-if)  ip ospf retransmit-interval  

Use the ip ospf hello-interval interface command to change the hello timer for OSPF. The default value of this command is interface-dependent. By default, hello packets are sent every 10 seconds on broadcast and point-to-point networks, and 30 seconds on NBMA networks. All neighbors residing on a network and area should have equal hello timers. The dead-interval and wait timer automatically are changed when the hello interval is changed.

Use the ip ospf dead-interval command to change the dead interval received by this interface. The timer has a default vault of four times that of the hello timer, 40 seconds for broadcast and point-to-point networks, and 120 seconds for NBMA networks. Recall that the dead interval is the time that has to pass before a neighbor receives a hello before declaring it "dead."

Use the ip ospf retransmit-interval command to change OSPF retransmission interval. All routers in the area should have the time set to the same value.