Understanding Cloud Networking: VPCs, Subnets, and Routing
Network architecture patterns, VPC design, and connectivity between cloud and on-premises.
Cloud networking is software-defined but the fundamentals persist: IP addressing, routing, firewalls, and DNS. VPCs are your private network boundaries in the cloud.
VPC Design Principles
Segment by environment and tier: public subnets for load balancers, private subnets for applications and data. Avoid overlapping CIDR blocks across VPCs and on-premises networks. Plan for growth.
Connectivity Patterns
VPN for quick hybrid links. Dedicated interconnect for production throughput. Transit gateways and hub-spoke topologies simplify multi-VPC routing. DNS resolution across boundaries needs explicit design.
Security Layers
Security groups are stateful firewalls at the instance level. NACLs for subnet boundaries. Private endpoints keep traffic off the public internet. Network policies in Kubernetes add another layer for pods.
Solid VPC design prevents the networking surprises that derail migrations and scale-out efforts.
Subnet Design Patterns
Use /24 subnets per availability zone for application tiers unless you have a documented reason to go smaller or larger. Reserve IP space for load balancers, NAT gateways, and future growth. Plan pod CIDR ranges separately when using Kubernetes with VPC-native networking to avoid overlap with node subnets.
Hybrid Connectivity
Site-to-site VPN is fast to set up but limited in throughput. Dedicated interconnect suits steady, high-volume traffic between on-premises data centers and cloud. Always design failover: a single VPN tunnel is a single point of failure.
Common Pitfalls
Adopting tools before defining outcomes leads to expensive experiments without business value. Copying another organization's architecture without understanding your constraints creates fragile systems. Skipping documentation means every new team member relearns lessons the hard way.
Getting Started
Define success metrics before implementation. Start with the smallest scope that proves value. Review results with stakeholders weekly during the first month. Iterate based on evidence, not assumptions.