This curriculum spans the technical breadth of a multi-workshop program on CDN load balancing, covering the same depth of configuration, automation, and operational trade-offs practiced in large-scale internal capability builds for global content delivery.
Module 1: Fundamentals of Traffic Distribution in CDNs
- Configure DNS-based load balancing to route user requests to the nearest Point of Presence (PoP) using geolocation data from authoritative DNS servers.
- Implement Anycast routing in conjunction with BGP to direct traffic to the topologically closest CDN node, balancing load across multiple regions.
- Decide between client-side and server-side load balancing based on application requirements for session persistence and failover behavior.
- Establish health check intervals and thresholds for edge nodes to prevent routing traffic to degraded or unreachable servers.
- Integrate real-time traffic telemetry into load distribution algorithms to respond dynamically to sudden traffic spikes or node outages.
- Design TTL values for DNS records to balance between rapid failover capability and DNS caching efficiency across recursive resolvers.
Module 2: Global Server Load Balancing (GSLB) Architectures
- Deploy GSLB appliances or cloud-based services to evaluate server availability, latency, and capacity across globally distributed data centers.
- Configure weighted load distribution policies to shift traffic proportionally based on node capacity, such as CPU utilization or bandwidth availability.
- Implement failover policies that redirect traffic from a failed region using DNS response manipulation or Anycast rerouting.
- Balance consistency and performance in GSLB state synchronization by choosing between active-active and active-passive configurations.
- Integrate third-party latency measurement services to augment internal metrics when determining optimal server selection.
- Manage DNS delegation and subdomain authority to ensure GSLB systems can respond authoritatively for CDN endpoints.
Module 3: Layer 4 vs. Layer 7 Load Balancing in CDN Edge Nodes
- Select Layer 4 (transport layer) load balancing for high-throughput TCP/UDP traffic where packet inspection overhead must be minimized.
- Implement Layer 7 (application layer) load balancers to inspect HTTP headers, cookies, and URL paths for intelligent content routing.
- Configure connection splicing in Layer 4 to reduce latency by forwarding traffic without full TLS termination at the edge.
- Deploy TLS offloading at Layer 7 to decrypt traffic at the edge, enabling content-aware routing and WAF integration.
- Assess trade-offs between connection pooling efficiency and client identity preservation when using Layer 7 reverse proxies.
- Mitigate head-of-line blocking in HTTP/1.x environments by tuning connection reuse and concurrency limits on Layer 7 balancers.
Module 4: Session Persistence and State Management
- Implement cookie-based session persistence when backend applications require user affinity, balancing stickiness with cache efficiency.
- Use IP hashing for stateless persistence in UDP-based services where cookies are not applicable.
- Design session replication or external state stores (e.g., Redis) to maintain user context across failover events.
- Evaluate the impact of sticky sessions on load distribution skew and plan capacity accordingly.
- Configure session timeout thresholds to release persistent mappings and allow rebalancing during traffic lulls.
- Encrypt session identifiers in cookies to prevent tampering while maintaining load balancer ability to route based on session data.
Module 5: Health Monitoring and Failover Automation
- Define multi-metric health checks combining HTTP status codes, response time, and server resource utilization to avoid false positives.
- Implement passive health monitoring by analyzing real user traffic patterns to detect node degradation without synthetic probes.
- Configure circuit breaker patterns to prevent cascading failures during backend service outages.
- Automate DNS TTL reduction during failover events to accelerate propagation of updated routing information.
- Integrate with incident management systems to trigger alerts and rollback procedures when health thresholds are breached.
- Test failover paths regularly using controlled traffic diversion to validate routing logic and recovery time objectives.
Module 6: Scalability and Capacity Planning for CDN Load Balancers
- Size virtual IP (VIP) capacity based on concurrent connections, throughput, and SSL/TLS handshake rates per load balancer instance.
- Implement horizontal scaling of load balancer clusters using auto-scaling groups tied to CPU, memory, and connection metrics.
- Design capacity buffers to absorb flash crowd events without triggering emergency scaling or performance degradation.
- Use predictive analytics on historical traffic patterns to schedule capacity increases before known peak periods.
- Optimize SSL session resumption and TLS cipher suite selection to reduce computational load on edge balancers.
- Monitor connection churn rates to identify potential DDoS indicators or misconfigured clients affecting balancer stability.
Module 7: Security and DDoS Mitigation in Load Distribution
- Deploy rate limiting at the load balancer level to mitigate Layer 7 DDoS attacks targeting specific URLs or endpoints.
- Integrate with Web Application Firewalls (WAF) to filter malicious payloads before they reach origin servers.
- Implement SYN flood protection using connection throttling and SYN cookies on Layer 4 load balancers.
- Use IP reputation feeds to dynamically block or challenge requests from known malicious networks.
- Configure geo-based access controls to restrict traffic from regions not served by the CDN, reducing attack surface.
- Enable detailed logging and audit trails for load balancer decisions to support forensic analysis during security incidents.
Module 8: Observability, Logging, and Performance Tuning
- Aggregate load balancer access logs with centralized monitoring tools to correlate request patterns with backend performance.
- Instrument custom metrics such as request queuing time, backend response latency, and retry rates for performance analysis.
- Configure distributed tracing across CDN nodes to identify latency bottlenecks in request routing paths.
- Use real user monitoring (RUM) data to validate that load balancing decisions improve end-user experience.
- Tune TCP stack parameters (e.g., buffer sizes, keepalive intervals) on load balancer instances to optimize connection handling.
- Conduct A/B testing of routing algorithms by directing subsets of traffic through different load balancing policies.