Low Latency EC2 Network Configurations

SAA-C03 By islever Editorial Last updated

Determine high-performing and/or scalable network architectures.

Short answer

AC Enable Enhanced Networking and run instances in a Cluster Placement Group to minimize inter-instance latency.

Question

A company is deploying an application that processes streaming data in near-real time. The company plans to use Amazon EC2 instances for the workload. The network architecture must be configurable to provide the lowest possible latency between nodes. Which combination of network solutions will meet these requirements? (Choose two.)
  1. Enable and configure enhanced networking on each EC2 instance. Correct Answer
  2. Group the EC2 instances in separate accounts.
  3. Run the EC2 instances in a cluster placement group. Correct Answer
  4. Attach multiple elastic network interfaces to each EC2 instance.
  5. Use Amazon Elastic Block Store (Amazon EBS) optimized instance types.

Key Takeaways

The question tests knowledge of network performance optimization, specifically identifying that physical proximity (Cluster Placement Group) and virtual packet efficiency (Enhanced Networking) are required together for minimal latency.

This question explores how to achieve the lowest possible latency between Amazon EC2 instances for near-real-time streaming data processing. It establishes that combining Cluster Placement Groups with Enhanced Networking is the standard solution.

Common mistake: Candidates often select EBS Optimized (E) because it relates to storage performance, or Multiple ENIs (D) assuming more interfaces equal better throughput, failing to distinguish between storage I/O and inter-instance network latency.

Expert Analysis

Why the Answer Is Correct

To achieve the lowest possible latency between nodes, you must address both the physical location of the hardware and the efficiency of the network stack. Option C, running instances in a Cluster Placement Group, ensures that all instances are physically located close to each other within a single Availability Zone, minimizing the distance data travels. Option A, enabling Enhanced Networking, utilizes Single Root I/O Virtualization (SR-IOV) to provide higher bandwidth and consistently lower inter-instance latencies by offloading networking tasks from the CPU. Together, these two solutions directly target the requirement for low-latency communication.

Why the Other Options Are Wrong

Option B (separate accounts) introduces no latency benefits and complicates management without improving network performance. Option D (multiple ENIs) allows for multiple IP addresses but does not inherently reduce latency between instances; it is primarily used for network segmentation or high availability. Option E (EBS Optimized) is designed to guarantee dedicated bandwidth for storage I/O between the instance and the EBS service, not for inter-instance network communication. While important for storage-heavy workloads, it does not address the specific requirement of low latency between compute nodes.

Community Comment Notes

The community consensus strongly supports AC, noting that cluster placement groups place instances physically close to reduce travel time for data. As user mestule noted, enhanced networking provides "higher bandwidth, higher packet per second (PPS) performance, and consistently lower inter-instance latencies." Some users debated option E, but the official guidance clarifies that EBS optimization is for storage, not network-to-network latency. User Andy_09 suggested CD, but this is incorrect as multiple ENIs do not guarantee lower latency than a single optimized interface in a cluster group.

Official Reference

These links open the official vendor documentation in a new tab.

Exam Strategy

Always pair physical placement strategies (like Cluster Placement Groups) with software/network optimizations (like Enhanced Networking) when the goal is maximum performance or lowest latency. Remember that 'EBS Optimized' is strictly for storage traffic, not general network traffic between instances.

Frequently Asked Questions

Why isn't EBS Optimized correct for low latency?

EBS Optimized guarantees bandwidth for storage I/O between the instance and EBS, not for network traffic between EC2 instances.

Can I use separate accounts for low latency?

No, separate accounts add administrative overhead and do not influence the physical network path or latency between instances.

More SAA-C03 FAQ →

Community Votes

AC
100%

100% of anonymous learners picked answer AC. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 7 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 7

  1. mestule 👍 12
    A. Enable and configure enhanced networking on each EC2 instance. Enhanced networking provides higher bandwidth, higher packet per second (PPS) performance, and consistently lower inter-instance latencies. C. Run the EC2 instances in a cluster placement group. A cluster placement group is a logical grouping of instances within a single Availability Zone. This configuration is recommended for applications that need low network latency, high network throughput, or both.
  2. AmirBe 👍 4
    AC Use of Placement Groups: Utilize EC2 Placement Groups to ensure that instances are physically located close to each other within the same Availability Zone. This reduces the latency between instances by minimizing the distance data needs to travel. Selection of EC2 Instance Types: Choose EC2 instance types optimized for low-latency networking, such as instances with enhanced networking capabilities like Elastic Network Adapter (ENA) or instances that support Amazon EC2 Nitro System. These instances provide high throughput and low latency networking performance.
  3. Sivaeas 👍 4
    To reach speeds up to 10 Gbps between instances, launch your instances in a cluster placement group with the enhanced networking instance type. These instance types are placed physically close to each other. Instance types that are close to each other further reduces latency and improves transfer speeds.
  4. FlyingHawk 👍 1
    A: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/enhanced-networking.html C: https://aws.amazon.com/ec2/instance-types/#Instance_Features Select EC2 instances support cluster networking when launched into a common cluster placement group. A cluster placement group provides low-latency networking between all instances in the cluster. The bandwidth an EC2 instance can utilize depends on the instance type and its networking performance specification.
  5. jaswantn 👍 1
    option C & E. Option A is not viable as ..EC2 provides enhanced networking capabilities using single root I/O virtualization (SR-IOV) only on supported instance types.
Show 2 more comments
  1. Andy_09 👍 1
    Correct option should be CD
  2. osmk 👍 1
    what's AM?

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