domain-id (OSPF)
Function
The domain-id command sets an ID for an OSPF domain.
The undo domain-id command restores the default setting.
By default, the domain ID is null.
Format
domain-id { null | domain-id [ type type value value | secondary ] * }
undo domain-id [ domain-id [ type type value value ] ]
Parameters
| Parameter | Description | Value |
|---|---|---|
| domain-id | Specifies the ID of an OSPF domain. | The value can be an integer or in dotted decimal notation.
|
| null | Indicates that the OSPF domain ID is null. | - |
| type type | Specifies the type of the OSPF domain ID. | It can be 0005, 0105, 0205, or 8005. By default, it is 0005. |
| value value | Specifies the value of the type of the OSPF domain ID. | The value is a hexadecimal number that ranges from 0x0 to 0xffff, and the default value is 0x0. |
| secondary | Indicates the ID of a secondary domain. | The maximum number of domain-id secondary in each OSPF process is 1000. |
Usage Guidelines
Usage Scenario
Domain IDs are used to identify domains.
If the local OSPF area and an OSPF area of a remote VPN attempts to exchange Type 3 LSAs, the two areas must be in the same OSPF domain. You can run the domain-id command to configure the same domain ID for the two OSPF areas.
The routes that are imported from a PE switch are advertised using External-LSAs. The routes destined for different nodes in the same OSPF domain are advertised based on Type 3 LSAs. This requires that the nodes in the same OSPF domain be configured with the same domain ID.
If the undo domain-id command without any parameter is executed, the primary domain ID will be deleted.
Configuration Impact
Before sending routes to a remote CE switch, a PE switch sends Type 3 LSAs or Type 5 LSAs to the CE based on domain ID. If local domain IDs are the same as or compatible with remote domain IDs in BGP routes, the PE advertises Type 3 routes. If local domain IDs are different from or incompatible with remote domain IDs in BGP routes, the PE advertises Type 5 routes.
Precautions
- Each OSPF domain has one or multiple domain IDs. One of them is a primary ID and the others are secondary IDs.
- If an OSPF instance does not have a specific domain ID, its ID is considered as null.
- If the value of the domain ID is 0, secondary cannot be configured.
- The maximum number of domain-id secondary items configured in an OSPF process is 1000.
- The domain-id command is forbidden in public networks.