Posted On: Nov 28, 2022

AWS announces the general availability of Elastic Network Adapter (ENA) Express for Amazon Elastic Compute Cloud (EC2) instances. All current generation EC2 instances use ENA, a purpose-built network interface, to deliver an enhanced networking experience. ENA Express is a new ENA feature that uses the AWS Scalable Reliable Datagram (SRD) protocol to improve network performance in two key ways: higher single flow bandwidth and lower tail latency for network traffic between EC2 instances.

Workloads such as distributed storage systems and live media encoding require large flows and are sensitive to variance in latency. Before today, customers could use multipath TCP to increase bandwidth, but this adds complexity and at times, it maybe incompatible with the application layer. TCP is also not equipped to handle congestion when your server is overloaded with requests. SRD is a proprietary protocol that delivers these improvements through advanced congestion control, multi-pathing, and packet reordering directly from the Nitro card. Enabling ENA Express is a simple configuration that makes enabling SRD as easy as a single command or console toggle for your EC2 instances. Using the SRD protocol, ENA Express increases the maximum single flow bandwidth of EC2 instances from 5 Gbps up to 25 Gbps, and it can provide up to 85% improvement in P99.9 latency for high throughput workloads. ENA Express works transparently to your applications with TCP and UDP protocols. When configured, ENA Express works between any two supported instances in an Availability Zone. ENA Express detects compatibility between your EC2 instances and establishes an SRD connection when both communicating instances have ENA Express enabled. Once a connection is established, your traffic takes advantage of SRD and its performance benefits. Detailed monitoring for these SRD connections is also available through new ethtool metrics available in the latest Amazon Linux AMI.

ENA Express is now available in all AWS Commercial Regions and It will initially be supported with the C6gn.16xl instance with more coming soon. ENA Express comes at no additional cost. To learn more and get started, please read our blog and review the latest EC2 documentation.