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Saloni Singh
Saloni Singh

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Learning AWS Day by Day — Day 75 — Elastic Network Interface

Exploring AWS !!

Day 75

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Elastic Network Interface

Logical networking component in a VPC that represents virtual network card.
When we move a network instance from one instance to another, network traffic is redirected to new instance.

Why do we need a network interface?
We will need to attach multiple network interfaces when:

  1. creating a management network
  2. Using network and security appliances in VPC
  3. Creating dual-homed instances with workloads/roles on distinct subnets
  4. Creating low-budget high availability solution.

Let’s walk through a scenario:
Using network interfaces, we can create a management network. Here, the primary network interface on the instance handles public traffic, and secondary network interface handles backend management traffic and is connected to separate subnet in our VPC which has more restrictive access controls.

Elastic Network Adapter:
EC2 provides enhanced networking capabilities through network adapter. It supports 100 Gbps network speed for supported instance types.

Elastic Fabric Adapter:
Network device that can be attached to EC2 to accelerate High Performance Computing (HPC) and Machine Learning applications.
In short, EFA is an ENA with more functionalities, providing an additional OS-bypass function, allowing HPC and ML apps to communicate directly over a network interface to achieve low latency.

Limitations of EFA:
Only one EFA per instance can be attached.
EFA traffic cannot be sent from one subnet to another. Only normal IP traffic can be sent. OS-bypass traffic is limited to single subnet.
EFA OS-bypass traffic cannot be routed , only IP traffic from EFA can be routed.
Security group needs to be attached to EFA that managed inbound and outbound traffic from security group itself.

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