Networking

AWS provides different types of network interfaces to optimize networking performance based on use cases. The three main network interfaces are Elastic Network Interface (ENI), Elastic Network Adapter (ENA), and Elastic Fabric Adapter (EFA). Here’s a comparison:

Feature	ENI (Elastic Network Interface)	ENA (Elastic Network Adapter)	EFA (Elastic Fabric Adapter)
Purpose	General-purpose networking	High-performance networking for EC2 instances	High-performance networking for HPC and ML workloads
Bandwidth	Up to 100 Gbps (depends on instance type)	Up to 200 Gbps (depends on instance type)	Similar to ENA but optimized for HPC and ML workloads
Traffic Type	Standard TCP/IP, IPv4 & IPv6	Standard TCP/IP, IPv4 & IPv6	Standard TCP/IP, SRD (Scalable Reliable Datagram)
Use Case	Basic networking, multi-interface setups	High-bandwidth applications, low-latency workloads	HPC (High-Performance Computing), ML training, tightly coupled workloads
Instance Support	Most EC2 instances	High-speed instance types (e.g., C5n, M5n, P4d)	Limited to specific HPC instances (e.g., p4d, c5n, dl1)
Enhanced Networking	No	Yes	Yes
SR-IOV Support	No	Yes	Yes
Latency	Moderate	Low	Ultra-low

Summary:

• ENI: A standard network interface used for general-purpose networking and multi-interface EC2 configurations.
• ENA: Provides enhanced networking with higher bandwidth and lower latency.
• EFA: Extends ENA with Scalable Reliable Datagram (SRD), which improves inter-node communication for HPC and ML workloads.

Feature	ENI (Elastic Network Interface)	ENA (Elastic Network Adapter)	EFA (Elastic Fabric Adapter)
Max Throughput	Up to 5 Gbps	Up to 200 Gbps	Up to 400 Gbps
Max Packets Per Second (PPS)	~100,000 PPS	Millions of PPS	Millions of PPS
Latency	Higher latency	Low latency	Ultra-low latency
Use Case	General-purpose networking	High-performance networking	HPC, ML, tightly coupled workloads
OS Bypass	No	No	Yes (for MPI-based workloads)