Announcing zone-aware routing in Amazon ECS Service Connect

This article announces zone-aware routing in Amazon ECS Service Connect, which automatically routes traffic to healthy endpoints in the same Availability Zone as the client.

• Reduces cross-AZ data transfer costs by prioritizing 80%+ of traffic within the same AZ when endpoints are balanced
• Delivers approximately 24% reduction in median network latency in multi-AZ deployments
• Enabled by default for new and existing services with no application code changes required
• Uses Envoy sidecar proxy to discover endpoints, prioritize local AZ traffic, and gracefully fall back to other AZs if needed
• Requires minimum of 2× endpoints per Availability Zone to activate; automatically disables if threshold drops
• Works with existing Service Connect features including service discovery and cross-account connectivity

Zone-aware routing is available in all AWS Regions supporting ECS, requiring only a one-time redeployment of existing services to activate.