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Network Lab Topology with Namespaces and netem

Run the Network Lab Topology with Namespaces and netem MicroSim Fullscreen

About This MicroSim

s:

This MicroSim is built with p5.js and is width-responsive, so it adapts to the width of the page or container it is embedded in.

How to Use

Use the controls in the panel below the drawing area to explore the concept. Adjust the sliders, toggle the options, and step through the stages to see how each change affects what is shown.

Specification

The full specification below is extracted from Chapter 15: Network Operations and Measurement.

Type: microsim
**sim-id:** virtual-network-lab<br/>
**Library:** p5.js<br/>
**Status:** Specified

Build an interactive MicroSim that visualizes a small Linux-host virtual network lab and lets students apply impairments to specific interfaces.

Canvas: 960 px wide by 600 px tall, responsive down to 360 px. A 120 px control panel sits below.

Topology:

- A single host containing 4 network namespaces: client, router, server-east, server-west.
- A Linux bridge `br0` connects client to router; another bridge `br1` connects router to both servers.
- veth pairs are drawn explicitly between namespaces and bridges.

Animation:

- A traffic source in `client` sends test packets to `server-east` or `server-west`. Packet animations show traffic flowing through the bridges and router.
- When tc netem is applied (via the controls), a small "impairment" badge appears on the affected interface, and packets visibly slow, get dropped, or reorder.
- A real-time stats panel shows RTT, throughput, and loss observed by the client.

Controls panel:

- Per-interface dropdowns to apply netem impairments: latency (0–500 ms), jitter (0–100 ms), loss (0–10%), reorder (0–10%).
- Test buttons: ping (send ICMP), iperf-style throughput, http GET (large file).
- Reset all impairments.
- Toggle: "Show command line" displays the equivalent `tc netem` and `ip netns` commands the simulation is emulating.

Visual style:

- Namespaces: rounded rectangles with namespace icons.
- Bridges: hexagons.
- veth pairs: dashed amber edges.
- Impairment badges: red for loss, blue for delay, green for reorder.
- Packets: small dots animated along edges.

Learning objectives:

- (Bloom — Understanding) Students explain how Linux namespaces and bridges build a virtual network on one host.
- (Bloom — Applying) Students choose and apply tc netem impairments to test specific application behaviors.
- (Bloom — Analyzing) Students decompose observed application behavior under impairment into its causes (delay, loss, reorder).

Implement in pure p5.js with the existing MicroSim CSS theme.

Iframe Embed Code

You can add this MicroSim to any web page by adding this HTML:

<iframe src="https://dmccreary.github.io/networking/sims/virtual-network-lab/main.html"
        height="502px"
        width="100%"
        scrolling="no"></iframe>

Lesson Plan

Learning Objective

s:

Bloom Taxonomy Level

Understand

Suggested Classroom Use

  1. Predict — Ask students to predict the behavior before they interact.
  2. Explore — Have students manipulate the controls and observe the results.
  3. Explain — Ask students to explain, in their own words, what they observed and how it connects to network operations and measurement.

References