Configuring OSPF route redistribution
On a router running OSPF and other routing protocols, you can configure OSPF to redistribute static routes, direct routes, or routes from other protocols, such as RIP, IS-IS, and BGP. OSPF advertises the routes in Type-5 LSAs or Type-7 LSAs. In addition, you can configure OSPF to filter redistributed routes so that OSPF advertises only permitted routes.
![[IMPORTANT: ]](images/important.png) | IMPORTANT: The import-route bgp command redistributes only EBGP routes. Because the import-route bgp allow-ibgp command redistributes both EBGP and IBGP routes, and might cause routing loops, use it with caution. | |
Redistributing routes from another routing protocol
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter OSPF view. | ospf [ process-id | router-id router-id | vpn-instance vpn-instance-name ] * | N/A |
3. Configure OSPF to redistribute routes from another routing protocol. | import-route protocol [ as-number ] [ process-id | all-processes | allow-ibgp ] [ allow-direct | cost cost-value | nssa-only | route-policy route-policy-name | tag tag | type type ] * | By default, no route redistribution is configured. This command redistributes only active routes. To view information about active routes, use the display ip routing-table protocol command. |
4. (Optional.) Configure OSPF to filter redistributed routes. | filter-policy { ipv4-acl-number | prefix-list prefix-list-name } export [ protocol [ process-id ] ] | By default, OSPF accepts all redistributed routes. |
Redistributing a default route
The import-route command cannot redistribute a default external route. Perform this task to redistribute a default route.
To redistribute a default route:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter OSPF view. | ospf [ process-id | router-id router-id | vpn-instance vpn-instance-name ] * | N/A |
3. Redistribute a default route. | default-route-advertise [ [ always | permit-calculate-other ] | cost cost-value | route-policy route-policy-name | type type ] * default-route-advertise [ summary cost cost-value ] | By default, no default route is redistributed. This command is applicable only to VPNs. The PE router advertises a default route in a Type-3 LSA to a CE router. |
Configuring default parameters for redistributed routes
Perform this task to configure default parameters for redistributed routes, including cost, tag, and type. Tags identify information about protocols. For example, when redistributing BGP routes, OSPF uses tags to identify AS IDs.
To configure the default parameters for redistributed routes:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Enter OSPF view. | ospf [ process-id | router-id router-id | vpn-instance vpn-instance-name ] * | N/A |
3. Configure the default parameters for redistributed routes (cost, upper limit, tag, and type). | default { cost cost-value | tag tag | type type } * | By default, the cost is 1, the tag is 1, and the type is Type-2. |