Building Resiliency For AWS Direct Connect Maintenance Events To Mitigate Downtime

This article provides advanced guidance on building resilient AWS Direct Connect architectures to withstand planned and unplanned maintenance events.

• Resiliency differs from redundancy; true resilience includes preparation, detection, response, recovery, and learning.
• Planned maintenance uses AS-Path prepend (60-second wait) then route withdrawal; emergency maintenance causes abrupt termination.
• AWS performs pre-checks and post-checks during maintenance to ensure device state and traffic continuity.
• Maximum Resilience topology: dual connections across two Direct Connect locations with separate endpoints per location.
• Active/active configurations require careful capacity planning to prevent congestion during single-link failures.
• Enable Bidirectional Forwarding Detection (BFD) to reduce failure detection from minutes to sub-millisecond.
• Use BGP Local Preference communities to control traffic routing before planned maintenance.
• Quarterly failover testing validates redundant connections and route exchange functionality.
• CloudWatch alarms and Network Synthetic Monitor provide continuous monitoring of Direct Connect usage.

Implementing Maximum Resilience topology with BFD, regular testing, and capacity planning ensures business continuity during Direct Connect maintenance.