Grading Checklist

• Checked /proc/net/bonding/bond0 to verify bond mode, slave status, and link detection settings
• Identified that miimon is set to 0 (disabled), meaning no link monitoring is active
• Recognized that without link monitoring, the bond cannot detect a link failure
• Checked ethtool on both interfaces to see if link detection at the NIC level works
• Investigated the switch port configuration for consistency with the bond mode
• Proposed setting miimon=100 (100ms polling) to enable link failure detection
• Considered arp_interval as an alternative or complement to miimon for upper-layer validation
• Verified both interfaces are properly enslaved and the bond mode is active-backup (mode 1)
• Tested the fix by shutting down the switch port again after applying miimon
• Recommended adding failover testing to regular maintenance procedures
• Addressed why the interface shows "UP" (kernel link state vs. bond link monitoring are independent)