Networking Fundamentals for Modern Applications

Networks are the backbone of modern applications. From mobile apps to cloud services, data travels across machines and networks every moment. A clear view of networking helps you design faster, safer, and more reliable software.

Core concepts you should know

  • TCP/IP basics: TCP provides reliable delivery; IP routes packets to the right host. Together they move data across the Internet.
  • DNS and routing: Names map to addresses, and routers guide packets. Caching reduces delay and speeds up startup.
  • Client-server and microservices patterns: Many apps split work into services. Each call adds latency, so design for clear interfaces and idempotence.

Protocols to know

  • HTTP/2 and HTTP/3: Multiplexing reduces round-trips and improves performance for web traffic.
  • TLS encryption: Encrypts data in transit, protects privacy, and builds trust.
  • API design and streaming: Different interactions suit different needs; choose the right pattern for your data.

Service discovery and load balancing

  • Service discovery lets services find each other without fixed addresses.
  • Load balancing spreads requests across healthy instances, boosting throughput and resilience.
  • In practice, an API gateway or a service mesh can manage access, security, and routing decisions.

Performance, reliability, and security

  • Caching at edges or inside services lowers load and speeds responses.
  • Backoff, retries, and idempotent operations reduce duplicate work after failures.
  • CDNs bring content closer to users for fast static assets.
  • TLS by default, certificate management, and regular rotation help keep connections secure.
  • Observability with metrics, logs, and traces helps spot bottlenecks and failures.
  • Define simple reliability targets (SLIs/SLOs) to guide improvements.

Practical example

A small web app with a frontend, an API, and a user service: a user visits the site, TLS ends at the API gateway, which authenticates and routes to the user service via service discovery. The response travels back through the gateway, with static assets served from a CDN.

Key Takeaways

  • Networking design affects performance and reliability.
  • Use clear, scalable patterns like DNS-based load balancing and TLS.
  • Observe, measure, and improve with simple SLIs.