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Configuring SPF parameters
When the LSDB changes on a router, a route calculation starts. Frequent route calculations consume a lot
of system resources. You can set an appropriate interval for SPF calculations to improve efficiency.
Follow these steps to configure the SPF parameters:
To do…
Use the command...
Remarks
Enter system view
system-view
—
Enter IS-IS view
isis
[
process-id
] [
vpn-instance
vpn-instance-name
]
—
Configure the SPF calculation
interval
timer spf
maximum-interval
[
initial-interval
[
second-wait-interval
] ]
Optional
The default SPF calculation
interval is 10 seconds.
Assigning a high priority to IS-IS routes
An IS-IS topology change causes network convergence. By assigning a high priority to specific IS-IS
routes, you can achieve faster network convergence.
Follow these steps to assign a high priority to IS-IS routes:
To do…
Use the command…
Remarks
Enter system view
system-view
—
Enter IS-IS view
isis
[
process-id
] [
vpn-instance
vpn-instance-name
]
—
Assign a high priority to IS-IS routes
priority high
{
ip-prefix
prefix-name
|
tag
tag-value
}
Optional
Not assigned by default
If no IS-IS route is assigned a high
priority, IS-IS host routes are
processed first in network
convergence because they have
higher priority than other types of
IS-IS routes.
Setting the LSDB overload bit
By setting the overload bit in sent LSPs, a router informs other routers of a failure that makes it incapable
of routing and forwarding packets.
When an IS-IS router cannot record the complete LSDB due to running out of memory or some other
reasons, it will calculate wrong routes. To make troubleshooting easier, you can temporarily isolate the
router from the IS-IS network by setting the overload bit.
Follow these steps to set the LSDB overload bit:
To do…
Use the command…
Remarks
Enter system view
system-view
—
Enter IS-IS view
isis
[
process-id
] [
vpn-instance
vpn-instance-name
]
—
