Network Simulator – Teacher Worksheet (Scenes 0–6)

Scene 0 – Welcome

Teacher aim: introduce the simulator as a simplified model.

• Discuss device roles and expectations.
• Clarify that “sensible design” matters more than perfection.

Scene 1 – Basic Office

• PCs → Switch → Server.
• Connect all the PCs to a new switch (outside of the sever room)
• Connect a switch to the Server in the Server Room)
• Ensure all devices are connected together, including the 2 switches

Scene 2 – Office with Security & Services

• Add a server for shared services
  
• Add a firewall think about where it needs to go
  
• AEnsure all internal devices use Ethernet
  
• Use Fibre only for the external internet link
  
Goal:

• A secure office network with correct device placement.

Focus: security boundaries and client–server.

Scene 3 – Open Lab (Performance)

This is a sandbox.
• Experiment freely with devices, cables, and load.
  
• Explore what causes congestion and how it can be reduced.
• Stress-test networks using load.
• Redesign to remove bottlenecks.

Focus: congestion and trade-offs.

Scene 4 – Enterprise Network (each Floor is a Zone)

• Design a multi-floor enterprise network
  
• Place switches and WAPs logically within the building
  
• Use Ethernet and Fibre where appropriate
  
• Ensure all wireless demand is covered
  
• Assume 3 servers are required
  
  

Focus: structured layout and scale.

Scene 5 – Internal office IP Configuration (single LAN - switches have been placed for you)

• NOTE: You will find you do not need to configure the router for your internal network to work!
• Add a PC to every desk and set IP
  
• Add one Server
  
• Connect all devices using Ethernet
  
• Configure IP address for every device (Note: Router cannot use static routes in this Scene)
  
• Use Ping or Send Message to test connectivity via IP or Hostnames
  
• Fix issues such as missing IPs or conflicts
  
What to learn:

• Failure messages tell you what was wrong.

Scene 6 – Wide Area Network (Routing)

• I suggest School uses 192.168.10.x and Trust uses 192.168.20.x
• Configure IP addresses for all devices in both separate LANs
  
• Test connections without a default gateway (some tests should fail)
  
• Add the correct default gateway IP before - Adding static routes Using Static Routes section only
  
• Ensure default gateway IP's are added to PC's and servers
  
• Test again and confirm it now works both internally and externally
• Add more switches and PCs and observe the impact, can you communicate with the LAN
  
• Test traffic across the WAN (packet animation shows the hops) between all PC's, servers etc
  
• You can connect uses IP address or Host names
  
• Rules: No NAT, no dynamic routing, no DNS. GCSE-level routing only.

Focus: routing and why gateways matter.

Failure messages (what they mean)

• No IP configured → device cannot communicate.
• IP conflict → duplicate addresses cause failure.
• Different network, no gateway → routing required.
• Gateway not reachable → addressing alone is not enough.

Rules in place (and why)

The rules are designed to enforce common classroom “correct network” patterns and prevent unrealistic shortcuts that confuse beginners.

• PC / PC x5 ↔ Switch (Ethernet only) — encourages the standard access-layer pattern.
• Server ↔ Switch (Ethernet only) — reinforces servers as shared resources on the LAN.
• Switch ↔ Switch (Ethernet or Fibre) — introduces uplinks/backbone thinking.
• Router ↔ Switch (Ethernet only) — keeps the router as the LAN gateway device.
• Scene 2+: Firewall ↔ Cloud (Fibre only) — shows “internet edge” and security boundary.
• No direct PC↔PC, PC↔Server, Router↔PC/Server — blocks misleading direct links and forces proper structure.
• Scene 4: zones/floors matter — teaches physical layout constraints and sensible distribution.
• Scene 4: WAP ↔ Switch (Ethernet only) — reinforces that WAPs still need wired backhaul.
• Scene 4: CAT8 cables in server room — To keep it simple these are by default, also allows more load on the cable.
• Scene 5: PC, Switch and Server only, kept simple — Students to test connectivity using IP.
• Scene 6: All devices except WAP, simpification used but students can test across IP ranges using routers.

Where I simplified for learning

• Traffic/load model is intentionally approximate: it’s there to reveal patterns, not measure real throughput.
• The first number shows current load, the 2nd number is the max load of the cable
• Congestion cues are simplified to “over threshold = congested” to keep discussion focused.
• Wi-Fi demand points (phones/tablets) translate complexity into an easy planning problem.
• Unmanaged switches, basic Layer 2, more like those used in homes, Layer 3 outside of spec, and adding IP's possible confuse students
• No DNS configured at this point. This may be built in at a later stage