ENA Express leverages the Scalable Reliable Datagram protocol to deliver enhanced networking performance, including advanced congestion control and multi-path routing, between EC2 instances in different Availability Zones within a region. This upgrade addresses limitations of previous 5 Gbps single-flow bandwidth between zones.
By detecting ENA Express compatibility, it establishes reliable connections that avoid head-of-line blocking and transparently improve TCP and UDP traffic throughput for applications requiring resilience across multiple Availability Zones, such as distributed storage and databases. This feature is available at no additional cost across many global AWS regions.
Source & further reading
ENA Express for Amazon EC2 instances now supports traffic between Availability Zones ↗Source published 2026-05-11. This report was prepared with AI assistance from the linked primary-source material. Claims and limitations should be checked against the original announcement or research.