vpn-instance-capability simple (OSPF)

Usage Scenario

If OSPF VPN multi-instance is deployed on a Multi-VPN-Instance CE (MCE), routes cannot be calculated based on Type3, Type5, or Type7 LSAs with the DN bit. Therefore, OSPF detects routing loops when calculating routes. In this case, the vpn-instance-capability simple command is used to disable OSPF routing loop detection and enable OSPF to calculate routes based on received LSAs without checking the DN bit and route-tag in the LSAs. The route-tag is restored to the default value 1.

Prerequisites

OSPF VPN multi-instance has been deployed on an MCE using the ospf process-id vpn-instance vpn-instance-name command.

Configuration Impact

• If there is no ABR and the vpn-instance-capability simple command is run on an MCE, the MEC cannot become an ABR.

• After the vpn-instance-capability simple command is run, OSPF routes that have been imported by BGP do not carry any OSPF domain ID, route tag, or router ID.

• By default, when BGP imports an OSPF route, it uses the cost of the OSPF route plus 1 as the MED value. The MED in BGP is similar to the cost in an IGP in terms of functions. After the vpn-instance-capability simple command is run, BGP uses the cost of an OSPF route as the MED when it imports the OSPF route. Therefore, MED values change after the command is run, which may affect the route selection result.

Precautions

The undo vpn-instance-capability command cannot be used to enable OSPF routing loop detection in a scenario without MCEs.