Multi-Region Cloud Network Architecture

A comprehensive guide for designing and implementing production-ready cloud network architecture focusing on AWS infrastructure.

Author

Ditah Kumbong

This documentation was initially generated using Claude AI and has been thoroughly reviewed, adjusted, and enhanced based on my professional experience in cloud infrastructure and network design.

Documentation Structure

• Networking Fundamentals - Core networking concepts and principles
• VPC Registry - CIDR allocation tracking (submit PR to claim VPCs)
• Diagrams - Visual architecture representations

Network Design Overview

Private IP Range Allocation (10.x.x.x)

• Canada (Primary): 10.0.0.0/12 (10.0.0.0 - 10.15.255.255)
• USA: 10.16.0.0/12 (10.16.0.0 - 10.31.255.255)
• Frankfurt: 10.32.0.0/12 (10.32.0.0 - 10.47.255.255)
• Singapore: 10.48.0.0/12 (10.48.0.0 - 10.63.255.255)

Environment Segmentation (per region)

Development:  10.{r}.0.0/16  - 10.{r}.3.0/16   (4 VPCs)
Staging:      10.{r}.4.0/16  - 10.{r}.7.0/16   (4 VPCs)
Production:   10.{r}.8.0/16  - 10.{r}.11.0/16  (4 VPCs)
Reserved:     10.{r}.12.0/16 - 10.{r}.15.0/16  (4 VPCs)

where {r} = region offset:
  0 for Canada, 16 for USA, 32 for Frankfurt, 48 for Singapore

Tier Segmentation (per VPC)

Example: Canada Production VPC (10.0.8.0/16)

Web Tier:     10.0.8.0/24 (AZ1), 10.0.9.0/24 (AZ2)
App Tier:     10.0.10.0/24 (AZ1), 10.0.11.0/24 (AZ2)
Database:     10.0.12.0/24 (AZ1), 10.0.13.0/24 (AZ2)
Management:   10.0.14.0/24 (AZ1), 10.0.15.0/24 (AZ2)

Design Principles

1. IP Address Pattern

Example: 10.0.12.25 breakdown:

• 10.0: Canada Region (/12 block)
• 12: Database subnet in Production VPC
• 25: Host number within subnet

2. Network Security Design

• Public subnets: Web tier with internet access
• Private subnets: App and DB tiers
• Protected subnets: Management and monitoring
• Each tier has dedicated security groups and NACLs

3. High Availability Design

• Minimum two AZs per region
• Active-Active configuration for web/app tiers
• Active-Standby for database tier
• Cross-AZ load balancing

4. Resource Distribution

Per Availability Zone:

• Web servers in public subnets
• Application servers in private subnets
• Database instances in protected subnets
• NAT Gateways in public subnets
• Load Balancers spanning all AZs

Network Architecture Diagrams

1. Global Network Design

   • Multi-region network structure
   • Regional connectivity
   • Transit Gateway design

2. Regional Network Design

   • VPC structure
   • Environment segmentation
   • CIDR allocation

3. Availability Zones Design

   • Multi-AZ layout
   • Subnet distribution
   • HA components

Implementation Best Practices

1. VPC Components

• One Internet Gateway per VPC
• NAT Gateway per AZ
• VPC Endpoints for AWS services
• Transit Gateway for inter-VPC routing

2. Security Implementation

Security Group Chain:

Web Tier SG:
- Inbound: 80/443 from Internet
- Outbound: To App Tier ports

App Tier SG:
- Inbound: From Web Tier only
- Outbound: To DB Tier ports

DB Tier SG:
- Inbound: From App Tier only
- Outbound: Updates only

3. Connectivity

• VPC Peering for direct connections
• Transit Gateway for hub-and-spoke
• Direct Connect for on-premises
• Site-to-Site VPN for backup

4. Monitoring

• VPC Flow Logs enabled
• CloudWatch metrics
• Network monitoring
• Security monitoring

Growth Considerations

1. Subnet Expansion

Initial Subnets (Canada Production VPC 10.0.8.0/16):
Web: 10.0.8.0/24 (AZ1), 10.0.9.0/24 (AZ2)
App: 10.0.10.0/24 (AZ1), 10.0.11.0/24 (AZ2)
DB:  10.0.12.0/24 (AZ1), 10.0.13.0/24 (AZ2)

Growth Subnets (additional capacity):
Web: 10.0.16.0/24 (AZ1), 10.0.17.0/24 (AZ2)
App: 10.0.18.0/24 (AZ1), 10.0.19.0/24 (AZ2)
DB:  10.0.20.0/24 (AZ1), 10.0.21.0/24 (AZ2)

2. Regional Expansion

• Keep consistent naming
• Use standard CIDR blocks
• Maintain security patterns
• Replicate monitoring setup

Quick Start Guide

1. Start with primary region setup
2. Implement basic networking components
3. Set up security groups and NACLs
4. Configure monitoring and logging
5. Expand to additional regions as needed

License

MIT