Assigning a high priority to is-is routes, Setting the lsdb overload bit – H3C Technologies H3C S12500 Series Switches User Manual

Page 175

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Step Command

Remarks

2.

Enter IS-IS view.

isis [ process-id ] [ vpn-instance
vpn-instance-name ]

N/A

3.

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.
To assign a high priority to IS-IS routes:

Step Command

Remarks

1.

Enter system view.

system-view

N/A

2.

Enter IS-IS view.

isis [ process-id ] [ vpn-instance
vpn-instance-name ]

N/A

3.

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 LSDP due to running out of memory or some other

reasons, it will calculate wrong routes. To make troubleshooting easier in this case, temporarily isolate

the router from the IS-IS network by setting the overload bit.
To set the LSDB overload bit:

Step Command

Remarks

1.

Enter system view.

system-view

N/A

2.

Enter IS-IS view.

isis [ process-id ] [ vpn-instance vpn-instance-name ]

N/A

3.

Set the overload bit.

set-overload [ on-startup [ [ start-from-nbr system-id
[ timeout1 [ nbr-timeout ] ] ] | timeout2 ] [ allow { external
| interlevel } * ]

Not set by default.

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