Imagine you and your friends are routers in a network. Each of you can only talk directly to three other routers, even though there are eight routers in total. Your goal is to figure out the best paths to reach all the other routers by sharing information with the three routers you can talk to. This activity helps you understand how real routers communicate and learn about paths in a network.
To make things clearer, let’s look at two example conversations between routers. These conversations show how routers exchange information to find the best paths to other routers.
Router F: Hi, I’m Router F.
Router C: I’m Router C. Let’s see if you have any paths to other routers. Do you know how to get to Router A?
Router F: I don’t have a connection to Router A yet.
Router C: Me neither. How about Router B?
Router F: Yes, I can reach Router B with a cost of 10.
Router C: Great! It costs me 2 to reach you, and 10 more to reach B through you. So, it costs me 12 to get to B. What about Router D?
Router F: I can reach D with a cost of 5.
Router C: And Router E?
Router F: No paths to E yet.
Router C: I can reach E with a cost of 1, so through you, it would be 3. What about Router G?
Router F: I have a path to G with a cost of 8.
Router C: So, it costs 10 to get to G through you. What about Router H?
Router F: I don’t have a path to H.
Router C: Hi, I’m Router C.
Router D: I’m Router D. Do you have a path to A?
Router C: No, I don’t.
Router D: I can get to A with a cost of 4.
Router C: So, it costs me 9 to get to A through you. What about B?
Router D: I can reach B with a cost of 10.
Router C: It costs me 15 to get to B through you, but I have a direct path that costs 6.
Router D: I can reach B through you with a cost of 11. What about E?
Router D: I have a path to E with a cost of 3.
Router C: That’s cheaper than my current path. It costs me 8 through you. What about F?
Router C: I can reach F with a cost of 2.
Router D: So, it costs me 7 to get to F through you. Do you have a path to G?
Router C: Yes, it costs 10.
Router D: And H?
Router C: No path to H.
Router D: I can reach H with a cost of 12, so it would be 17 through you.
Remember, you can only talk to the three routers you’re directly connected to. But if you talk to them again later, they might have new information about shorter paths they’ve learned. Keep sharing and learning to find the best routes. Enjoy the activity!
Pair up with a classmate and act out the conversations between routers, just like in the examples. Take turns being different routers and practice sharing path information. This will help you understand how routers communicate and learn about network paths.
Create a visual map of the network using paper and markers. Draw the routers and the connections between them. As you learn about new paths from your classmates, update your map to reflect the shortest paths. This activity will help you visualize how routers find the best routes.
Work in small groups to calculate the cost of different paths between routers. Use the information from your role-playing conversations to determine the shortest path to each router. This game will reinforce your understanding of how routers calculate path costs.
Challenge yourself to connect all eight routers using the fewest number of connections. Discuss with your classmates how different configurations affect the path costs and the efficiency of the network. This challenge will help you think critically about network design.
Reflect on what you learned about router communication and pathfinding. Discuss with your classmates how these principles apply to real-world networks. This discussion will deepen your understanding of how routers work in the internet.
In this activity, you and your classmates will be acting as routers in a connected network of eight routers. However, you’ll only have direct paths to three of the other seven routers. During the activity, you can only communicate with those three routers. You will engage in a series of conversations with the three routers you are connected to in order to exchange information about paths to other routers in the network. These conversations simulate how real routers learn about paths to other routers in the network that they are not directly connected to.
Often, it’s easier to understand an activity by seeing a demonstration rather than reading about it. You are about to see a set of two conversations: one between routers C and F, and then a conversation between routers C and D.
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**Conversation 1:**
**Router F:** Hi, I’m Router F.
**Router C:** I’m Router C. Since you’re F, I’m going to fill out the third column of my sheet to see your best paths to the other routers in the network. Do you have any connections to Router A?
**Router F:** I do not yet have any connections to Router A.
**Router C:** Neither do I. What about Router B?
**Router F:** I have a connection of 10 to Router B.
**Router C:** Okay, I’m going to write that down. So it costs me 2 to get to you, and it costs you 10 to get to B. So it costs me 12 to get to B going through you. What about Router D? Do you have a connection?
**Router F:** I do. My shortest connection is 5, which means I can get to D with a cost of 7.
**Router C:** What about Router E? Do you have a path?
**Router F:** I have no paths to E yet.
**Router C:** Okay, I do, with a cost of 1. So I can get to E through you with a cost of 3. Perfect!
**Router F:** I’m Router F, and I know how to get to myself, but what about Router G? Do you have a path?
**Router C:** I do not have a path to G.
**Router F:** Okay, I have a path to G with a cost of 8. So that’s 10 to get to G through you. Perfect! What about Router H?
**Router C:** I have no paths to H either.
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**Conversation 2:**
**Router C:** Hi, I’m Router C.
**Router D:** I’m Router D. Do you have a path to A?
**Router C:** I still do not have a path to A.
**Router D:** Well, I can get there at a cost of 4.
**Router C:** Okay, so through D, it costs me 5 to get to you, plus 4 to get to A. So that’s 9 to get to A through you. Do you have a path to B?
**Router D:** I do, and it’s a cost of 10.
**Router C:** So it costs me 5 to get to you, plus 10, which is 15. I also have a path to B, and it costs me 6.
**Router D:** So it takes me 5 to get to you, plus 6, which is 11. That’s not my cheapest, but I do have it through you now.
**Router C:** So I know how to get to you, and I am C. What about E?
**Router D:** I have a route to E at a cost of 3.
**Router C:** So that’s 5 plus 3, which is 8. That is cheaper than my current one; I can get there at a cost of 10.
**Router D:** So through you, I could get to E with a cost of 15, but that’s not cheaper than my current one. Do you have a path to F?
**Router C:** I do, and it’s a cost of 2.
**Router D:** So that’s 5 plus 2, which is 7 for me. What about a path to G?
**Router C:** I have a path to G, and it’s a cost of 10.
**Router D:** Then do you have a path to H?
**Router C:** I have no path to H.
**Router D:** All right, I can get to H at a cost of 12. So it costs you 12, and it takes me 5 to get to you, which is 17 to get to H.
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Remember that in the activity, you can only talk to your three connected routers, but you may find that if you go back to a router a second time, they’ll have new information about a shortest path that they’ve learned about. Have fun!
Routers – Devices that forward data packets between computer networks, directing the data along the most efficient paths. – Example sentence: The routers in our school ensure that all students can access the internet quickly and efficiently.
Network – A group of interconnected computers and devices that can share resources and communicate with each other. – Example sentence: Our school’s computer network allows us to access shared files and printers from any classroom.
Paths – Routes that data packets take through a network to reach their destination. – Example sentence: The software calculates the best paths for data to travel to minimize delays.
Communicate – To exchange information between devices or systems in a network. – Example sentence: Computers communicate with each other using specific protocols to ensure data is sent and received correctly.
Information – Data that is processed and organized in a meaningful way for communication or analysis. – Example sentence: The database stores information about all the students, including their grades and attendance records.
Cost – The amount of resources, such as time or data, required to perform a task or operation in computing. – Example sentence: Optimizing the code reduced the cost of running the program on our servers.
Reach – The ability of a network or device to connect and communicate with other networks or devices. – Example sentence: Expanding the Wi-Fi coverage increased the network’s reach to include the entire campus.
Activity – Any operation or process performed by a computer or network, such as data transfer or program execution. – Example sentence: Monitoring network activity helps identify potential security threats.
Sharing – The act of allowing multiple users or devices to access and use resources like files or printers in a network. – Example sentence: File sharing on the network makes it easy for students to collaborate on group projects.
Learning – The process of acquiring knowledge or skills through study or experience, often enhanced by technology and online resources. – Example sentence: Online coding platforms provide interactive learning experiences for students interested in programming.
