vpn-instance-capability simple

Function

The vpn-instance-capability simple command enables OSPF to directly calculate routes without conducting the routing loop detection.

The undo vpn-instance-capability command detects the DN bit to prevent routing loops.

The vpn-instance-capability simple command enables the device to directly calculate routes instead of conducting routing loop detection.

The undo vpn-instance-capability command enables a device to check the DN bit in received summary LSAs (Type 5 and Type 7 LSAs) to prevent routing loops and check the DN bit and route tag in the received ASE LSAs to prevent routing loops.

By default, the routing loop detection is enabled.

Format

vpn-instance-capability simple

undo vpn-instance-capability

Parameters

None

Views

OSPFv3 view, OSPF view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
ospf	write

Usage Guidelines

Usage Scenario

When OSPF/OSPFv3 VPN multi-instance is deployed on a multi-VPN-instance CE (MCE), if the DN bit is set in Type 3, Type 5, or Type 7 LSAs or the route tag carried in Type 5 or Type 7 LSAs is the same as the locally configured route tag, these routes cannot be calculated because loop detection is performed during OSPF/OSPFv3 route calculation. In this case, you can run the vpn-instance-capability simple command to disable OSPF/OSPFv3 routing loop detection and enable the devce to calculate all OSPF/OSPFv3 routes without checking the DN bit or route tag.

If VPN multi-instance is supported on a multi-VPN-instance CE (MCE) device, routing loop detection must be disabled. The vpn-instance-capability simple command takes effect only in OSPF/OSPFv3 VPN instances.

Prerequisites

OSPF/OSPFv3 VPN multi-instance has been deployed on an MCE using the ospf vpn-instance command.

Configuration Impact

After the vpn-instance-capability simple command is run on an MCE, the MCE will not become an ABR if OSPF or OSPFv3 backbone area 0 is not configured.
If the import-route bgp command is run in the OSPF process bound to a VPN instance, IBGP routes will not be imported to the VPN process after the vpn-instance-capability simple command is run unless permit-ibgp is specified in the import-route bgp command.
After the vpn-instance-capability simple command is run, OSPF/OSPFv3 routes imported by BGP do not carry the OSPF/OSPFv3 domain ID, OSPF/OSPFv3 route type, or OSPF/OSPFv3 router ID.
By default, when BGP imports an OSPF or OSPFv3 route, the Multi_Exit Discriminator (MED) value (similar to the metric used in an IGP) is the OSPF cost plus 1. After the vpn-instance-capability simple command is run, the MED value is changed to the OSPF/OSPFv3 cost value. As a result, the MED values of the OSPF or OSPFv3 routes imported by BGP change, affecting BGP route selection.

Precautions

The undo vpn-instance-capability simple command cannot be used to enable OSPF/OSPFv3 routing loop detection in a scenario without MCEs.

Example

# Disable loop detection.

<HUAWEI> system-view
[~HUAWEI] ip vpn-instance huawei
[*HUAWEI-vpn-instance-huawei] ipv6-family
[*HUAWEI-vpn-instance-huawei-af-ipv6] quit
[*HUAWEI-vpn-instance-huawei] quit
[~HUAWEI] ospfv3 100 vpn-instance huawei
[*HUAWEI-ospfv3-100] vpn-instance-capability simple

# Disable routing loop detection.

<HUAWEI> system-view
[~HUAWEI] ip vpn-instance vrf1
[*HUAWEI-vpn-instance-vrf1] route-distinguisher 100:1
[*HUAWEI-vpn-instance-vrf1-af-ipv4] vpn-target 3:3 export-extcommunity
[*HUAWEI-vpn-instance-vrf1-af-ipv4] vpn-target 4:4 import-extcommunity
[*HUAWEI-vpn-instance-vrf1-af-ipv4] quit
[*HUAWEI-vpn-instance-vrf1] quit
[*HUAWEI] ospf 100 vpn-instance vrf1
[*HUAWEI-ospf-100] vpn-instance-capability simple