OSPFv3 timers
Timers in OSPFv3 include the following:
OSPFv3 packet timer
LSA delay timer
SPF timer
GR timer
OSPFv3 packet timer
Hello packets are sent periodically between neighboring routers for finding and maintaining neighbor relationships, or for DR or BDR election. The hello interval must be identical on neighboring interfaces. The smaller the hello interval, the faster the network convergence speed and the bigger the network load.
If a router does not receive a hello packet from a neighbor within a given period—dead interval, it then declares the peer down.
After sending an LSA to its adjacency, a router waits for an acknowledgment from the adjacency. If no response is received after the retransmission interval elapses, the router will send the LSA again. The retransmission interval must be longer than the round-trip time of the LSA.
LSA delay time
Each LSA has an age in the local LSDB (incremented by one per second), but an LSA does not age on transmission. You must add an LSA delay time into the age time before transmission, which is important for low-speed networks.
SPF timer
Whenever the LSDB changes, an SPF calculation occurs. If recalculations become frequent, a large amount of resources will be occupied. You can adjust the SPF calculation interval and delay time to protect networks from being overloaded by frequent changes.
GR timer
If a failure to establish adjacencies occurs during a GR, the device will be in the GR process for a long time. To avoid this, configure the GR timer for the device to exit the GR process when the timer expires.