Changing the standby-only interface parameter causes a link flap

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Article ID: 168061

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Updated On:

Products

XOS

Issue/Introduction

Explains why adding or removing the standby-only parameter for an interface on the NPM-8200 or NPM-8210 can result in a short interface flap, and how to avoid an unexpected interface failover.Unexpected interface failover after adding or removing the interface parameter standby-only.

Cause

Problem: The parameter standby-only configures an interface to be used as a backup interface. When changing this parameter on the NPM-8200 or NPM-8210, the interface will go down briefly, as shown below:
 
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Feb 24 17:35:44 Xbeam cli: USER: admin, COMMAND: CBS# configure interface gigabitethernet > configure interface gigabitethernet 1/8 standby-on
 
Feb 24 17:35:46 npm1 tPhyTimerProc: [I] ethsw_port_down: 1.8: down
Feb 24 17:35:50 npm1 tPhyTimerProc: [I] ethsw_port_up: 1.8: up.
 
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Feb 24 17:36:08 Xbeam cli: USER: admin, COMMAND: CBS# configure interface gigabitethernet > configure interface gigabitethernet 1/8 no standby
 
Feb 24 17:36:10 npm1 tPhyTimerProc: [I] ethsw_port_down: 1.8: down
Feb 24 17:36:14 npm1 tPhyTimerProc: [I] ethsw_port_up: 1.8: up.
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Resolution

To avoid an unexpected interface failover:

Be careful when changing the standby-only parameter for an interface that is configured as a redundant interface and is currently active in the redundant interface pair. The resulting link flap will cause an unexpected interface failover.

Before changing the parameter, verify which interface is active with the CLI command show redundancy-interface.

Workaround

N/A