Level 2 · Associate

Cisco Certified Network Associate (CCNA · 200-301)

The classic foundation of networking. The CCNA teaches the underlying logic of how the entire internet works — which is why it's valued even by cloud giants like Amazon and Microsoft. This is the level that makes me job-ready: every topic below gets learned, labbed, broken and proven.

# Syllabus — The 6 Official Domains

Official 200-301 exam blueprint with Cisco's exact domain weightings. This is the single most important checklist on this site — the CCNA is the foundation everything else builds on.

My CCNA progress0 / 0
1. Network Fundamentals 20%
2. Network Access 20%
3. IP Connectivity 25%
4. IP Services 10%
5. Security Fundamentals 15%
6. Automation & Programmability 10%

# Hands-On Labs

These build on each other into one growing "company network" — exactly how real enterprises evolve. All lab files get committed to this repo.

LAB 01 — VLAN & Trunking: Segment the Office

3 switches, 3 departments (Sales, Engineering, Guest). Create VLANs, configure access & trunk ports, verify isolation, then add inter-VLAN routing (router-on-a-stick, then SVIs on a L3 switch).

Real-world case: HR demands their traffic be isolated from the guest Wi-Fi for compliance — the most common segmentation request in any company.
Packet TracerCompliance segmentation

LAB 02 — Spanning Tree & EtherChannel: Survive a Cable Loop

Build a redundant switch triangle. Identify the root bridge, predict blocked ports, fail a link and watch reconvergence. Bundle links with LACP EtherChannel.

Real-world case: Someone plugs both ends of a cable into the same switch and the floor goes down — STP knowledge is why it doesn't.
Packet Tracer / GNS3Loop prevention

LAB 03 — Subnetting a Real Company

Given 172.16.0.0/16 and a brief (4 sites, different host counts, room to grow), design a VLSM addressing plan, document it, and implement it across the topology.

Real-world case: Your company acquires a smaller firm — you must design address space that won't collide and won't run out. Architects do this for a living.
Spreadsheet + Packet TracerIP plan design

LAB 04 — OSPF: Connect Three Branches

3 routers in single-area OSPF. Verify adjacencies, influence DR/BDR election, advertise a default route, break an adjacency (mismatched timers) and troubleshoot it back.

Real-world case: A branch office drops off the network after a change window — "show ip ospf neighbor" is your first command, and you'll know why.
GNS3 / Packet TracerBranch outage

LAB 05 — Internet Edge: NAT, ACLs & DHCP

One edge router: PAT to a simulated ISP, DHCP pools for internal VLANs, extended ACLs blocking guest VLAN from internal subnets while allowing internet.

Real-world case: This is, almost line for line, the config of every small/medium business internet edge in production today.
Packet TracerInternet edge build

LAB 06 — HSRP: Kill a Router, Stay Online

Two gateways running HSRP. Ping continuously from a client, power off the active router, measure the failover. Tune priority and preemption.

Real-world case: A core router dies at 2 PM on a Tuesday. With FHRP done right, users never notice. That's the job.
GNS3Redundancy / failover

LAB 07 — Harden the Network

SSH-only management, port security on access ports, DHCP snooping, dynamic ARP inspection. Then attack your own lab: plug in a rogue DHCP server and watch snooping block it.

Real-world case: An intern's home router (plugged in for "more ports") starts handing out wrong IP addresses to the whole floor. DHCP snooping is the fix.
Packet Tracer / GNS3Rogue device defense

LAB 08 — First Automation: Python Meets the Network

Use Python + Netmiko to SSH into your GNS3 routers: back up all configs, push a banner to 5 devices at once, and parse "show" output into JSON.

Real-world case: "Change the SNMP community on 200 switches by Friday." Manually: a week. Scripted: 10 minutes. This is the skill that separates 2026 engineers.
Python + NetmikoGNS3 / DevNet SandboxBulk config change

# Tools & Simulators for This Level

Cisco Packet Tracer

Covers ~90% of CCNA topics and includes wireless controller simulation. Start here.

Free

GNS3

Graduate here for OSPF/HSRP/automation labs — real IOS behavior, real SSH for your Python scripts.

Free

Boson ExSim / NetSim

The gold-standard practice exams — harder than the real thing. If you pass Boson, you pass the CCNA.

Jeremy's IT Lab (YouTube)

The best free complete CCNA course — full video series with free Packet Tracer labs for every lesson.

Free

Anki (flashcards)

Spaced repetition for port numbers, AD values, STP states, OSPF timers. 15 min/day.

Free

subnettingpractice.com

Daily subnetting drills until sub-15-second answers. The exam is time-pressured; this is how you bank time.

Free
Reality check: plan 3–6 months at 1–2 hrs/day. The #1 reason people fail is skipping labs and only watching videos. Hands-on time should be ≥40% of total study time.

# Growth Check — After This Level

Skills I Now Own

  • Design an IP addressing plan (VLSM) for a multi-site network and implement inter-VLAN routing across it.
  • Deploy and troubleshoot OSPF — including diagnosing broken adjacencies under pressure.
  • Build a complete internet edge: NAT, ACLs, DHCP, and HSRP redundancy with measured failover.
  • Automate with Python + Netmiko — config backups and bulk changes across many devices.

Self-Check Before the Exam

  • Can I subnet any question in under 15 seconds?
  • Given an STP topology, can I predict the root bridge and blocked ports before checking?
  • Can I read any line of show ip route and explain every field?
  • If an OSPF adjacency is stuck, do I know the 6 mismatches to check, in order?

My Next Growth Step

  • Rebuild Labs 01–07 from blank configs without looking at notes — proof it's learned, not memorized.
  • Add Linux fundamentals and deepen Python — they multiply everything at CCNP level.
  • Start reading the ENCOR Official Cert Guide casually before formally beginning Level 3.
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