Simple AWS Network Cost Saving Tips But Most People Miss

 

Here is the key scenarios you have to remember:
 

Scenario	Cost Behavior
EC2 → EC2 in same AZ, private IP	Free
EC2 → EC2 in different AZs	$0.01/GB (intra-region data transfer)
EC2 → EC2 in different Regions	$0.02/GB (Inter-region data transfer)
EC2 → Internet via public IP	$0.09/GB (data transfer out to internet)
EC2 → S3 or other services	Varies, often incurs cross-service charges

These charges can quietly accumulate, especially in high-throughput architectures or data-intensive pipelines.

 

💡Tip 1: Use Private IPs for Internal Communication

Using a public IP between AWS resources — even in the same region — routes traffic out through the internet gateway and back in. That incurs public data transfer charges.

Instead:

• • Configure your EC2 instances, containers, or services (like RDS or ElastiCache) to use private IPs or DNS names resolving to private IPs.

• • Place your resources in private subnets and use VPC peering or Transit Gateway when needed — both support private routing.

Savings: Avoid the $0.09/GB outbound charge when you don’t need public exposure.

Bonus: It also improves latency and security by keeping traffic within AWS’s private backbone.

 

💡 Tip 2: Deploy Services in the Same Availability Zone (AZ)

Even within the same VPC and region, cross-AZ traffic is not free. AWS charges $0.01/GB for data transferred between AZs.

Here’s how to optimize:

• • Place tightly-coupled services (e.g., EC2 + RDS, EC2 + Elasticsearch) in the same AZ when high data exchange is expected.

• • Use placement groups if needed to keep compute instances in close proximity.

• • Be cautious with autoscaling and multi-AZ deployments — great for availability, but may increase cross-AZ traffic if not managed carefully.

Example: A microservice-based architecture with chatty inter-service communication can rack up significant intra-region fees when containers span multiple AZs.

 

📉 FinOps Wins: Simple Choices, Compounding Results

Let’s look at a quick cost example:

Scenario	Data Transfer	Monthly Cost (at 10 TB)
EC2 to EC2 in same AZ, private IP	10 TB	$0
EC2 to EC2 across AZs	10 TB	$100
EC2 to Internet (public IP)	10 TB	$900

That’s a 9× difference between private and public IP usage for the same amount of traffic.

 

🛠️ Implementation Checklist

• • Use private DNS names or IPs for all internal traffic

• • Configure VPCs to prioritize private subnets

• • Audit services communicating across AZs

• • Use placement groups or AZ-aware service discovery

• • Educate dev teams: cross-AZ ≠ free

 

📊 Monitor and Visualize: Add It to Your FinOps Dashboard

Include networking cost metrics in tools like:

• • Grafana (via Athena + CUR)

• • Looker Studio (via BigQuery or GCS exports)

• • AWS Cost Explorer → Use filters for “Data Transfer”

Track KPIs like:

• • Cost per GB transferred

• • Cross-AZ data transfer volume

• • Public IP egress cost trends

 

🧭 Final Thoughts

AWS networking costs are predictable and avoidable — but only if you design with awareness. By defaulting to private IPs and same AZ placement, you can significantly reduce spend while improving speed and security.

This is low-hanging FinOps fruit that every team should pick.

 

📣 Call to Actons

Ready to make smarter networking choices? Start by analyzing your VPC flow logs and CUR data to identify public IP or cross-AZ patterns. Then, refactor deployments or automate placement strategies to optimize for cost and performance.