ospf
Function
The ospf command creates and runs an OSPF process.
The undo ospf command terminates an OSPF process.
By default, OSPF is disabled, that is, no OSPF process runs.
Format
ospf [ process-id | router-id router-id ] *
undo ospf process-id [ flush-waiting-timer time ]
Parameters
| Parameter | Description | Value |
|---|---|---|
| process-id | Specifies the ID of an OSPF process. | The value is an integer ranging from 1 to 65535. By default, it is 1. |
| router-id router-id | Specifies a router ID. | It is in dotted decimal notation. |
| flush-waiting-timer time | Indicates the interval for generating aged LSAs. The parameter takes effect only when it is set. | The value is an integer that ranges from 1 to 40, in seconds. |
Usage Guidelines
Usage Scenario
You can set OSPF parameters only after creating an OSPF process.
OSPF supports multi-process. More than one OSPF process can run on the same device, and is independent of each other. Route interaction between different OSPF processes is similar to route interaction between different routing protocols.
The ID of an OSPF device can be configured manually. If no ID is specified through a command for an OSPF device, the system automatically selects an IP address of the interface as the router ID. The second largest IP address in loopback addresses is taken as the router ID. If no loopback interface is configured, the second largest IP address configured on the interface is selected as the router ID.
- The ospf command is used to re-configure an OSPF router ID.
- The system router ID is re-configured, and then the OSPF process is restarted.
- The IP address of the original system router ID is deleted, and then the OSPF process is restarted.
Configuration Impact
After an OSPF process is disabled by using undo ospf command, the receive end still maintains the LSAs generated by this OSPF process. These invalid LSAs occupy the system memory and are deleted only when the LS age field (aging time) reaches 3600 seconds. When the undo ospf process-id flush-waiting-timer time command is used to stop an OSPF process, the wireless access controller regenerates an LSA in the set time and sets the LS age field to 3600 seconds. After other wireless access controllers receive the LSA with the LS age field as 3600 seconds, they delete the LSA immediately. If the host does not send all the LSAs in the set time, other wireless access controllers still reserve invalid LSAs.
When the LS age field (aging time) in the LSA header reaches 3600 seconds, this LSA is deleted.
Precautions
An interface on a device belongs to only one OSPF process.
The router ID of each OSPF process must be unique on the entire network; otherwise, the OSPF neighbor relationship cannot be set up and routing information is incorrect. Configuring a unique router ID for each OSPF process on each OSPF device is recommended.
