Networking

Author

K19G

Published

October 31, 2026

Updated

October 31, 2026

Networking

Personal notes on learning computer networking from first principles to expert NetOps, with labs built as code in Containerlab using open-source and free network images only (FRR, Linux, optional SR Linux / SONiC / VyOS).

Note

This book is vendor-agnostic. CLIs differ; protocols do not. Start with the lab platform (macOS/Linux + Containerlab), then a deep networking foundations pass (TCP/IP, addressing, core protocols), then L2 → L3 → routing → edge → policy → overlays → fabrics → ops. Topology figures are illustrated SVGs under images/.

Distribution layer switch with four multi-homed host racks and /31 uplinks

Distribution switch with multi-homed servers

Curriculum map

Part Focus
01 Lab platform macOS/Linux host setup, Containerlab, free images, host networking, hygiene
02 Networking foundations TCP/IP stack, packets, Ethernet intro, IPv4/IPv6, ARP/ND, ICMP, TCP/UDP, common apps, host routing, planes
03 Layer 2 Ethernet/MAC deep, VLANs, loops, LAG, failure drills
04 Layer 3 Advanced addressing/routing labs, statics, ICMP/PMTU in multi-hop designs
05 Interior routing OSPF, BGP, policy & filters
06 Ops & automation Observability, lab-as-code, capstone outline
07 Edge & services First-hop HA, DHCP/NAT in edge designs, hygiene, dual-home lab
08 Policy, QoS, hardening ACLs, CoPP, QoS vocabulary, hardening
09 Overlays & tunnels Encap, site tunnels, VXLAN, Tailscale underlay between offices, EVPN intro
10 Fabrics & multi-area Clos, multi-area OSPF, FRR fabric, multi-NOS
11 BGP security A deep dive into BGP, RPKI, routing attacks, and global Internet defense
12 Network forensics Cyber-behavioral analysis, forensic telemetry, ML/AI detection, SIEM pipelines, and incident response

Journey map

Lab platform (macOS / Linux + Containerlab)
  → Networking foundations (TCP/IP, addressing, protocols)
  → Layer 2 depth
  → Layer 3 / routing depth
  → Interior routing (OSPF, BGP)
  → Edge & services
  → Policy / QoS / hardening
  → Overlays & tunnels
  → Fabrics
  → Ops & automation
  → BGP security at production scale
  → Network forensics & cyber-behavioral science

What “done” looks like

  • Design multi-site L2/L3 networks with clear underlay vs overlay roles
  • Implement them in Containerlab with free images
  • Prove behavior with tables, neighbors, and packet captures
  • Break links and policies on purpose; restore and document
  • Automate lab lifecycle

Lab ground rules

  • Prefer free/open node kinds (Containerlab + FRR + Alpine/Debian)
  • Every serious lab: topology file + addressing plan + failure scenario
  • Capture evidence when it teaches something tables do not

Formats

HTML, PDF, and EPUB via the monorepo portal when built.