Now that you understand how to distribute traffic (Module 1), it’s time to understand how the underlying communication layers work and, critically, how they fail.

This module focuses on the network and protocol layer: the behavior of TCP vs QUIC, the complexities of HTTP/2 and gRPC, and the harsh reality of network partitions in distributed systems.

Key topics include:

  • Modern Networking Primitives: TCP tuning, BBR congestion control, and the shift to UDP-based QUIC/HTTP3.
  • Protocol-Level Complexities: HTTP/2 multiplexing, gRPC streaming, WebSockets, and how protocol choice affects load balancing and tail latency.
  • Network Partitions & Split-Brain: Quorum systems, fencing mechanisms, and operational recovery patterns when the network lies.

Unlike Module 1’s focus on “distributing requests across servers,” this module asks: “What happens on the wire between those servers, and what breaks?”

Module Chapters