Public vs private subnet?

Public subnets have direct internet access via Internet Gateway. Private subnets access internet only through NAT Gateway for outbound traffic.

How do I size my subnets?

Use CIDR notation. /24 gives 256 IPs (251 usable), /20 gives 4096 IPs. Plan for growth - it's hard to resize subnets later.

Subnet

Definition

A subdivision of a virtual network that segments resources by IP range for security, organization, routing control, and efficient management.

Use Cases

Stripe: PCI-Compliant Architecture — Uses private subnets to isolate payment processing from public traffic (Maintains PCI DSS Level 1 compliance for billions in transactions)

Provider Equivalents

AWS: Subnet
Azure: Subnet
GCP: Subnetwork
OCI: Subnet

Frequently Asked Questions

Public vs private subnet?: Public subnets have direct internet access via Internet Gateway. Private subnets access internet only through NAT Gateway for outbound traffic.
How do I size my subnets?: Use CIDR notation. /24 gives 256 IPs (251 usable), /20 gives 4096 IPs. Plan for growth - it's hard to resize subnets later.

Subnet in Cloud Architecture

Understanding Subnet is important for cloud engineers and developers with foundational cloud experience. Cloud architects encounter this concept when designing systems for reliability, scalability, security, and cost-efficiency across Amazon Web Services (AWS), Microsoft Azure, Google Cloud Platform (GCP), and Oracle Cloud Infrastructure (OCI).

In cloud Networking, Subnet is one of several foundational concepts that practitioners must master to design production-ready systems. Related concepts in the same domain include the terms listed in the See Also section below.

Canvas Cloud AI provides an AI-powered designer for cloud architecture diagrams where practitioners can visualise how Subnet fits into a broader system. Users describe their architecture in plain English and receive a diagram, Terraform export, and Learning Guide — all without leaving the browser.

Category: networking

Difficulty: intermediate