PacketShaper input interface of a NIC pair goes down but the corresponding output interface remains up

Products

• PS-S500

Issue/Introduction

This article explains why a PacketShaper output interface may remain in an 'up' state even when its paired input interface has gone down. This behavior occurs when link state mirroring is not enabled.

Environment

PacketShaper S-Series (PS-S500, PS-S200, PS-S400)

Cause

The mirrorLinks system variable is disabled. When link state mirroring is disabled, the PacketShaper does not automatically bring down the second port of a NIC pair if the first port fails.

Resolution

Verify and enable the mirrorLinks setting using the PacketShaper CLI.

1. Log in to the PacketShaper CLI.
2. Check the current setting of the mirrorLinks variable: setup variable mirrorLinks
3. If the 'Current ' value is 0, enable it by running: setup variable mirrorLinks 1
4. Verify the change by running the command in step 2 again.

Additional Information

When mirrorLinks is enabled, the appliance ensures that both ports in a pair maintain the same link state. This is critical for network topologies that rely on link-loss detection to trigger failover.