Networking

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 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, EVPN intro
10 Fabrics & multi-area	Clos, multi-area OSPF, FRR fabric, multi-NOS

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

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

Related books

Book	Overlap
Linux	Host networking commands (ip, ss, tcpdump, firewalls)
NixOS	Declarative network config on NixOS hosts
Go	net/http, probes, and load-test projects
VCS	Lab-as-code repos and CI for topology files

Formats

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