The prefix-priority command sets the convergence priority of IS-IS routes.
The undo prefix-priority command restores the default convergence priority of IS-IS routes.
By default, the convergence priority of IS-IS host routes and default routes is medium, and the convergence priority of other IS-IS routes is low.
prefix-priority [ level-1 | level-2 ] { critical | high | medium } { ip-prefix prefix-name | tag tag-value }
undo prefix-priority [ level-1 | level-2 ] { critical | high | medium }
| Parameter | Description | Value |
|---|---|---|
| level-1 | Specifies the convergence priority of Level-1 IS-IS routes. | - |
| level-2 | Specifies the convergence priority of Level-2 IS-IS routes. | - |
| critical | Sets the convergence priority of IS-IS routes to critical. | - |
| high | Sets the convergence priority of IS-IS routes to high. | - |
| medium | Sets the convergence priority of IS-IS routes to medium. | - |
| ip-prefix prefix-name | Sets the convergence priority of the IS-IS routes matching the specified IP prefix. | The value is a string of 1 to 169 case-sensitive characters without spaces. |
| tag tag-value | Sets the convergence priority of the IS-IS routes with the specified tag value. To use the tag value to filter the IPv4 routes for which convergence priorities need to be set, ensure that the IS-IS cost style of sent packets is not narrow and the routes carry the tag value. | The value is an integer that ranges from 1 to 4294967295. |
When a routing table has a large number of routing entries on an IS-IS device, the device needs to spend much time performing SPF calculation. To enable some key routes to be calculated first, run the prefix-priority command to set the convergence priority for these routes.
The convergence priorities of IS-IS routes are classified as critical, high, medium, and low in descending order.
Existing IS-IS routes are converged based on the priorities set using the prefix-priority command.
New IS-IS routes are converged based on the priorities set using the prefix-priority command.
If an IS-IS route conforms to the matching rules of multiple convergence priorities, the highest convergence priority is used.
If the route level is not specified, the prefix-priority command configuration takes effect for both Level-1 and Level-2 IS-IS routes.
The prefix-priority command applies only to the public network.
After the prefix-priority command is run to set the convergence priority for IS-IS routes (including IS-IS host routes and default routes), the convergence priority of all the IS-IS routes that meet the matching rules is changed according to the command configuration, and the convergence priority of the IS-IS routes that do not meet the matching rules is changed to low.
# Set the convergence priority of Level-1 routes with tag value 3 to critical.
<HUAWEI> system-view
[HUAWEI] isis 1
[HUAWEI-isis-1] prefix-priority level-1 critical tag 3
# Set the convergence priority of the routes matching IP prefix p1 to medium.
<HUAWEI> system-view
[HUAWEI] ip ip-prefix p1 permit 192.168.0.1 24
[HUAWEI] isis 1
[HUAWEI-isis-1] prefix-priority medium ip-prefix p1