---
title: Routers and Redundancy
units: [The Internet]
summary: Not all messages take the same path to get to their destination.
weight: 170
---

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## Today's Objectives
- Describe how the redundant nature of networks can lead to dynamic, fault tolerant routes.
- Explain how data is routed through the Internet.

## Lesson Overview
### Routers, redundancy, and fault tolerance, oh my...
{{% define "Router" %}}
{{% define "Redundancy" %}}
{{% define "Fault Tolerant" %}}

## Assignment
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### Internet Simulator
Get in a group of 4-6, as you did in the previous lesson.

Use the updated version of the Internet Simulator on Code.org to send a message saying hello to everyone in your group.

Notice everyone now has an IP address.

Open the Log Browser.

Look at the messages.

View all messages (including other routers).

Use the Router Logs to choose an IP address from each of the other routers.

Send each person a message asking who they are and choose one of the following questions:

- What is your favorite food?
- What is your favorite type of animal?
- What is your favorite color?

_Be sure to also respond to questions you get from people on other routers!_

Open the Router Logs again. You should see a lot more messages now.

Pick someone on a different router and send three separate messages with your top three favorite movies or TV shows.

After you send the messages, open the router logs and find these same messages in the logs. Notice how these messages traveled through the network. Did they always take the same path from your router to the other router?

Look at other messages that are being sent. Are there any patterns in the paths they take?

Record your answer to the following question in complete sentences:

- What did you notice about the messages you sent in the router logs?

{{% unit-journal-define-terms "Router" "Redundancy" "Fault Tolerant" %}}
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