avoid-microloop frr-protected (OSPF view)

Function

The avoid-microloop frr-protected command enables OSPF anti-microloop.

The undo avoid-microloop frr-protected command disables OSPF anti-microloop.

By default, OSPF anti-microloop is disabled.

Format

avoid-microloop frr-protected

undo avoid-microloop frr-protected

Parameters

None

Views

OSPF view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
ospf	write

Usage Guidelines

Usage Scenario

OSPF remote LFA FRR is enabled, the primary link is PE1 -> P1 -> P2 -> PE2, and the backup link is PE1 -> P1 -> P3 -> P4 -> P2 -> PE2, and the link P1 -> P3 -> P4 is an LDP tunnel. If the primary link fails, traffic is switched to the backup link, and then another round of the new primary link calculation begins. Specifically, after P1 completes route convergence, its next hop becomes P3. However, the route convergence on P3 is slower than that on P1, and P3's next hop is still P1. As a result, a temporary loop occurs between P1 and P3. OSPF anti-microloop can address this problem by delaying P1 from switching its next hop until the next hop of P3 becomes P4. Then traffic is switched to the new primary link (PE1 -> P1 -> P3 -> P4 -> P2 -> PE2), and on the link P1 -> P3 -> P4, traffic is forwarded based on IP routes.

OSPF anti-microloop applies only to OSPF remote LFA FRR.

Prerequisites

OSPF has been enabled using the ospf command.

Example

# Enable OSPF anti-microloop.

<HUAWEI> system-view
[~HUAWEI] ospf
[*HUAWEI-ospf-1] avoid-microloop frr-protected