3Com Switch 8800 Advanced Software V5 Configuration Guide

332 CHAPTER 30: OSPF CONFIGURATION
n
■ The hello and dead intervals restore to default values after you change the
network type for an interface.
■ The dead interval should be at least four times the hello interval on an
interface.
■ The poll interval is at least four times the hello interval.
■ The retransmission interval should not be so small for avoidance of unnecessary
LSA retransmissions. In general, this value is bigger than the round-trip time of
a packet between two adjacencies.
Configuring the LSA
Transmission Delay
Since OSPF packets need time for traveling on links, extending LSA age time with
some delay time is necessary, especially for low speed links.
To configure the LSA transmission delay time on an interface, use the following
commands:
Configuring the SPF
Calculation Interval
Link State Database changes lead to SPF calculations. When an OSPF network
changes frequently, a large amount of network resources will be occupied,
reducing working efficiency of routers. You can adjust the SPF calculation interval
for the network to reduce negative influence. To do so, use the following
commands:
n
With this command configured, when network changes are not frequent, SPF
calculation applies at the minimum-interval. If network changes become frequent,
SPF calculation interval is incremented by incremental-interval¬²2
n-2
(n is the
number of calculation times) each time a calculation occurs, up to the
maximum-interval.
Specify the retransmission
interval
ospf timer retransmit
interval
Optional
The retransmission interval
defaults to 5 seconds.
To do... Use the command... Remarks
To do... Use the command... Remarks
Enter system view system-view -
Enter interface view interface interface-type
interface-number
-
Set the LSA transmission
delay time
ospf trans-delay seconds Optional
Set to 1 second by default
To do... Use the command... Remarks
Enter system view system-view -
Enter OSPF view ospf [ process-id | router-id
router-id | vpn-instance
instance-name ] *
-
Set the SPF calculation
interval
spf-schedule-interval
maximum-interval [
minimum-interval [
incremental-interval ] ]
Optional
By default, the interval is 5
seconds