Lesson 13: Geographic Distribution Strategy
Building Global Twitter Architecture That Actually Works
What We're Building Today
Today we transform our single-region Twitter MVP into a globally distributed system spanning three continents. You'll implement intelligent traffic routing, tackle real-world latency challenges, and understand why Instagram loads instantly in Tokyo but your app might not.
Key Deliverables:
Multi-region deployment across US, Europe, and Asia-Pacific
Intelligent traffic routing based on user location
CDN integration for static assets and timeline caching
Compliance-aware data placement for GDPR and regional laws
Real-time latency monitoring and automatic failover
Core Concepts: The Physics of Global Communication
The Speed of Light Problem
Network packets travel at roughly 200,000 km/second through fiber optic cables. From New York to Tokyo (10,800 km), that's a minimum 54ms each way - before any processing delays. This physical reality shapes every decision in global system design.
Geographic Distribution Patterns
Edge Locations: Serve static content (images, videos, CSS) from locations closest to users
Regional Data Centers: Host application logic and regional user data
Global Coordination: Synchronize critical data across regions while respecting data sovereignty
Latency Impact on User Experience
Research shows 100ms latency increase causes 1% revenue drop for e-commerce. For social media, where engagement drives everything, sub-200ms response times across all regions become critical for user retention.
Context in Distributed Systems: Twitter's Global Challenge
Real-World Scale Reference
Twitter serves 450+ million monthly active users across 190+ countries. A single tweet from a celebrity can generate millions of interactions within minutes, requiring coordination across dozens of data centers.
Component Integration
Our geographic distribution layer sits between the load balancer (previous lesson) and application servers, making intelligent routing decisions before requests reach our business logic.
Week 2 Scale Target
We're targeting 10,000 concurrent users distributed globally, with 90% experiencing sub-200ms response times regardless of their geographic location.
Architecture: Three-Layer Global Distribution
