The prefix-priority command sets a convergence priority for OSPF routes.
The undo prefix-priority command restores the default convergence priority of OSPF routes.
By default, the convergence priority of public 32-bit host routes is medium, and the convergence of other OSPF routes is low.
prefix-priority { critical | high | medium } ip-prefix ip-prefix-name
undo prefix-priority { critical | high | medium }
| Parameter | Description | Value |
|---|---|---|
| critical | Sets the convergence priority of OSPF routes to critical. | - |
| high | Sets the convergence priority of OSPF routes to high. | - |
| medium | Sets the convergence priority of OSPF routes to medium. | - |
| ip-prefix ip-prefix-name | Specifies the name of an 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. |
Usage Scenario
The prefix-priority command sets a convergence priority for OSPF routes according to a specified IP prefix list name. It takes effect on the public network only.
After the prefix-priority command is run in the OSPF view, OSPF route calculation, link-state advertisement (LSA) flooding, and LSDB synchronization can be implemented according to the configured priority, which accelerates route convergence.
Prerequisites
An IP prefix list has been created using the ip ip-prefix command in the system view.
Configuration Impact
When an LSA meets multiple priorities, the highest priority takes effect.
With the prefix-priority command, OSPF can calculate and flood LSAs, and synchronize LSDBs according to priorities. This speeds up route convergence. OSPF calculates LSAs in the sequence of intra-area routes, inter-area routes, and AS external routes. This command makes OSPF calculate the three types of routes separately according to the specified route calculation priorities. Convergence priorities are critical, high, medium, and low. To speed up the processing of LSAs with the higher priority, during LSA flooding, the LSAs need to be placed into the corresponding critical, high, medium, and low queues according to priorities.
Precautions
By default, the convergence priorities of public OSPF host routes, direct routes, static routes, and other protocol (such as BGP and RIP) routes are medium, high, medium, and low respectively. In the public network, OSPF 32-bit host routes are uniformly identified as medium.