interfaces <interface> <interface-name> ip ospf retransmit-interval <interval>
Sets the OSPF retransmission interval for an interface.
Unacknowledged LSAs are retransmitted at five-second intervals.
- interface
- A type of interface. For detailed keywords and arguments that can be specified as interface types, refer to Supported Interface Types.
- interface-name
- The name of an interface.
- interval
- The time, in seconds, to wait for an acknowledgment after which the system retransmits an LSA packet to its neighbors. The interval ranges from 5 to 65535. The default interval is 5 seconds.
Configuration mode
interfaces {
interfaces interface-name {
ip {
ospf {
retransmit-interval interval
}
}
}
}Use this command to specify how long an interface will wait for an acknowledgment of a link-state update before resending the update.
The LSU packet is part of the exchange of topology databases between routers. When the initial database description (DD) packet is sent, it contains only the headers of the link-state advertisements (LSAs). If the receiving router determines that it requires that piece of the OSPF topology, it sends a link-state request packet to request the complete LSA from the sending router.
After the update packet is sent, the sending router waits for an acknowledgement, either implicit or explicit, from the receiving router. In an explicit acknowledgement, the receiving router sends a link-state acknowledge (LS-Ack) packet to the router that sent the update. In an implicit acknowledgement, the router that sent the update receives an LSA from the receiving router that contains the update information.
If the retransmission interval passes with neither an explicit nor an implicit acknowledgement, the sending router retransmits the LSU packet.
Too high an interval slows network convergence. Too small an interval causes unnecessary retransmission.
Use the set form of this command to set the OSPF retransmission interval for an interface.
Use the delete form of this command to restore the default OSPF retransmission interval, which is 5 seconds, for an interface.
Use the show form of this command to display the OSPF retransmission level for an interface.