Networking

TCP/IP protocols, routing, and modern network architecture

Every web page, message, and video travels through an intricate network of connections. This hub follows a single packet’s journey, then descends into the layers beneath it: the protocol stack, addressing and routing, queueing and congestion control, performance and security, and finally modern architecture (edge, 5G, and software-defined networking). Start with the end-to-end packet story below, then work through the pages in the order suggested at the bottom.

The Journey of a Network Packet

Let’s start with something familiar: what happens when you type a URL and press Enter? This simple action triggers a cascade of network operations that this guide uses to explore fundamental concepts.

First, your browser needs to find the server. It sends a DNS query to translate the domain name into an IP address. This query itself is a network packet that must navigate through routers, switches, and servers to reach its destination. Along the way, it encounters the same challenges that all network traffic faces: congestion, routing decisions, and potential delays.

sequenceDiagram
    participant B as Browser
    participant D as DNS Resolver
    participant S as Web Server
    B->>D: DNS query: example.com?
    D-->>B: 93.184.216.34
    B->>S: TCP SYN (open connection)
    S-->>B: SYN-ACK
    B->>S: ACK + TLS handshake
    B->>S: HTTP GET /
    S-->>B: 200 OK + HTML
    Note over B,S: Each arrow is one or more packets routed hop-by-hop

Each arrow in that diagram unpacks into a whole subject. The DNS lookup and TLS handshake are application and transport protocols; “routed hop-by-hop” is routing and switching; the layered headers that wrap the data are the stack and addressing; and how fast it all completes is a performance question. The pages below follow that progression.

Explore Networking

Page What it covers
Layers & Addressing OSI and TCP/IP models, encapsulation, IPv4/IPv6, CIDR subnetting
Transport & Application Protocols TCP congestion control, TCP vs UDP, HTTP/DNS/DHCP/SSH, well-known ports
Routing & Switching Shortest-path and max-flow algorithms, BGP, OSPF, static/dynamic routing, NAT, VLANs
Performance, QoS & Security Queueing models, firewalls, VPNs, ACLs, QoS, troubleshooting, SNMP/NetFlow
Modern & Future Networking Hub: how networks evolve, plus research frontiers (ICN, quantum, 6G)
Programmable Networks SDN, NFV, P4, MPLS, and segment routing (SR/SRv6)
Cloud Networking VPCs, subnets, route tables, load balancers, CDNs, NAT, shared responsibility
Wireless & Mobile Wi-Fi (802.11), 4G/5G, the 5G core, spectrum, modulation, mobility

Suggested reading order

Read Layers & Addressing first to fix the vocabulary, then Transport & Application Protocols and Routing & Switching for how data actually moves, followed by Performance, QoS & Security. With those foundations, start the Modern & Future Networking hub, then dive into its three deep dives — Programmable Networks, Cloud Networking, and Wireless & Mobile — in any order.

Key Takeaways

  • Layers separate concerns. The OSI/TCP-IP stack lets each layer evolve independently — the same browser works over Wi-Fi, fiber, or cellular.
  • IP routes, TCP/UDP deliver. IP gets packets to the right host hop-by-hop; transport-layer ports and reliability decide which app gets them and how.
  • Performance is a queueing problem. Latency, jitter, and loss come from queues filling at bottleneck links — congestion control exists to keep them stable.
  • Congestion control keeps the net alive. Algorithms like Reno (loss-based) and BBR (model-based) continuously match sending rate to available capacity.
  • Routing scales hierarchically. OSPF optimizes paths inside an organization; BGP exchanges policy-driven routes between the internet’s autonomous systems.
  • Networks are becoming software. SDN, NFV, P4, and eBPF move forwarding logic into programmable software, enabling 5G slicing and in-network computing.

See Also

  • Cybersecurity — network security and zero-trust architecture
  • AWS — cloud networking, VPC, and Direct Connect
  • Docker — container networking and overlay networks
  • Kubernetes — cluster networking and CNI plugins
  • Quantum Computing — quantum networking and QKD