The prefix-priority command sets the convergence priority for IS-IS routes.
The undo prefix-priority command restores the default convergence priority of IS-IS routes.
By default, the convergence priority of 32-bit IS-IS host routes is medium and that 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 | Specifies the convergence priority of IS-IS routes to critical. | - |
| high | Specifies the convergence priority of IS-IS routes to high. | - |
| medium | Specifies the convergence priority of IS-IS routes to medium. | - |
| ip-prefix prefix-name | Specifies the name of the IP prefix list for filtering routes. It is case-sensitive. You can set the convergence priority of IS-IS routes which prefix list matches the specified IP prefix list. | The name is a string of 1 to 169 case-sensitive characters, with spaces not supported. When double quotation marks are used around the string, spaces are allowed in the string. |
| tag tag-value | Specifies the tag value for filtering routes. The cost-style of the IS-IS that needs to send packets should not be narrow and the IS-IS route must carry the tag value. You can set the convergence priority of IS-IS routes with the specified tag value. | The value is an integer ranging from 1 to 4294967295. This parameter has no default value. |
Usage Scenario
When a routing table has a large number of routing entries on an IS-IS device, the router takes a long time to implement the SPF calculation. To implement the SPF calculation for some key routes first, run the prefix-priority command to set convergence priorities for specified routes.
The convergence priority of existing IS-IS routes is re-set according to the configuration of the prefix-priority command.
The convergence priority of new IS-IS routes is set according to the filtering result of the prefix-priority command.
If an IS-IS route meets the matching rules specified in multiple commands that are used to configure convergence priorities, this IS-IS route is of top convergence priority among the set convergence priorities.
If no level is specified, the convergence priority is set for both Level-1 routes and Level-2 routes according to the configuration of the prefix-priority command.
The prefix-priority command is only applicable to the public network.
Prerequisites
Before running the prefix-priority command, run the isis command to create an IS-IS process and enter the IS-IS view.
Precautions
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 configuration of the prefix-priority command, 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 the Level-1 IS-IS routes with the tag value being 3 to critical.
<sysname> system-view
[sysname] isis 1
[sysname-isis-1] prefix-priority level-1 critical tag 3
# Set the convergence priority of the IS-IS routes with prefix-name as p1 to medium.
<sysname> system-view
[sysname] ip ip-prefix p1 permit 192.168.0.1 24
[sysname] isis 1
[sysname-isis-1] prefix-priority medium ip-prefix p1