H3C Technologies H3C S12500 Series Switches - Manual (Page 103)

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Configuring OSPF packet timers
You can configure the following timers on OSPF interfaces as needed:
• Hello timer—Interval for sending hello packets. It must be identical on OSPF neighbors. The longer
the interval, the lower the convergence speed and the smaller the network load.
• Poll timer—Interval for sending hello packets to a neighbor that is down on the NBMA network. The
poll interval is at least four times the hello interval.
• Dead timer—Interval within which if the interface receives no hello packet from the neighbor, it
declares the neighbor is down. The dead interval should be at least four times the hello interval on
an interface.
• LSA retransmission timer—Interval within which if the interface receives no acknowledgement
packets after sending a LSA to the neighbor, it retransmits the LSA. An interval setting that is too
small can cause unnecessary LSA retransmissions. This interval is typically set bigger than the
round-trip time of a packet between two neighbors.
To configure timers for OSPF packets:
Step Command Remarks
1. Enter system view. system-view N/A
2. Enter interface
view. interface interface-type
interface-number
N/A
3. Specify the hello
interval.
ospf timer hello seconds
Optional.
The hello interval defaults to 10 seconds on P2P
and broadcast interfaces, and defaults to 30
seconds on P2MP and NBMA interfaces.
The default hello interval is restored when the
network type for an interface is changed.
4. Specify the poll
interval.
ospf timer poll seconds
Optional.
The poll interval defaults to 120 seconds.
5. Specify the dead
interval.
ospf timer dead seconds
Optional.
The default dead interval is 40 seconds on P2P
and broadcast interfaces and 120 seconds on
P2MP and NBMA interfaces.
The default dead interval is restored when the
network type for an interface is changed.
6. Specify the
retransmission
interval.
ospf timer retransmit interval
Optional.
The retransmission interval defaults to 5
seconds.
Specifying an LSA transmission delay
Each LSA in the LSDB has an age that is incremented by 1 every second, but the age does not change
during transmission. It is necessary to add a transmission delay into the age time especially for low-speed
links.
To specify the LSA transmission delay on an interface: