Network Layer

What is an IP address?

Claimed By: Thames, Tamako

Answer: Internet Protocol address. It is the unique identifying number assigned to every device connected to a computer network that uses the Internet Protocol for communication. The network layer assigns IP addresses.

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(Internet Protocol is the set of rules governing the format of data sent via the internet or the local network.)

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The changes to your IP address usually only happen when you connect to a different network (like going from home to a coffee shop) or when your Internet Service Provider needs to assign you a new address.

Network Layer

What happens if there are multiple possible paths to a destination? How does the network choose the best one?

Claimed By: Jimin Yim and Melanie Jiménez

Answer:

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1. Internet as Roads: The internet is like a giant network of roads, and data (like emails or videos) are cars traveling to specific destinations.
2. Routers as Traffic Cops: Each router acts like a traffic cop, checking a map to decide which road (path) the data should take next.
3. Best Path Selection: The router picks the best road based on rules, like the shortest route, fastest road, or the one with the least traffic.
4. Handling Multiple Routes: If there are several good roads, the data cars might take different routes or switch if one road gets blocked.
5. Always Moving: If a road breaks or gets jammed, the routers automatically redirect the cars onto new roads to ensure the data still reaches its destination.

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Network Layer

How does data find its way to a server at the other end of the world?

Claimed By: Emmy , Zuka

Answer: A server first uses DNS to resolve a domain name into an IP address. Then, using the data that you send it, the data is then broken into packets and routed through a series of interconnected routers and networks across the world until it reaches the server. After the server processes the data, the response follows the same path back to your device, often in milliseconds, due to the optimized infrastructure of the internet.

Network Layer

Transport Layer

How does your computer know which app should receive incoming data, like a website in your browser or a video call app? Hint: PORTs

Claimed By: Shashi, Safi

Answer: Ports are like "mailboxes" on a computer. Incoming data arrives at the computer's "address" (IP address), and the port number determines which application the data belongs to. This system ensures the right app receives the right data, whether it's for browsing, video calls, or any other service. When multiple applications use the same port, typically only one application can bind to a specific port at a time on the same IP address.

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Transport Layer

When you send a message, how do you ensure it arrives at the correct destination, in the right order, and without errors?

Claimed By: Enxian Fu, Eleonore Wen

Answer:

• Correct Destination TCP/IP addressing ensures messages reach the right destination through:
• IP addresses that uniquely identify each device on the network
• Port numbers that specify which application should receive the data
• The TCP handshake process (SYN, SYN-ACK, ACK) that establishes a connection between specific endpoints

Transport Layer

Session Layer

When you log in to a website, how does the server remember that you’re logged in while you browse different pages?

Claimed By: Lydia and Yash

Answer: Imagine you're at an amusement park, and you get a special wristband when you enter.

Getting In: When you show your ticket and get your wristband, it's like logging into a website with your username and password.

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Unique Wristband: This wristband has a special number, just for you. It's like the server giving you a "session ID" when you log in to the website.

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Wristband Tracks You: As you walk around the park, everyone who sees your wristband knows you have a ticket, so you don't need to show your ticket again. On a website, this is like the website knowing you’re logged in every time you visit a new page, without asking for your password again.

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Staying Logged In: As long as you keep wearing your wristband, you can enjoy all the rides. On a website, as long as your "session" is active, you can browse the site without needing to log in again.

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Logging Out: When you leave the park and take off your wristband, it's like logging out of the website. You can't use it again until you get a new one (log in again).

Session Layer

How do we maintain a conversation between computers? What are cookies?

Claimed By: Bhavani and Gerald

Answer: When two computers want to communicate, a “meeting” is set up between the two - this involves setting up rules (how long the connection will last, etc.) and has checkpoints to make sure that if connection is lost, it can be picked up from the last checkpoint. Essentially, it starts the conversation smoothly and ensures it also terminates smoothly.

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Cookies are bits of information about the user that the website saves and uses it when user moves from page to page or returns the website later to help enhance web experience

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Session Layer

Presentation Layer

Do you think the way data is stored in a computer is the same as how it is sent over the Internet?

Claimed By: Brandon and Roberto

Answer: The Presentation Layer bridges the gap between stored data and transmitted data. It ensures that the data's format, structure, and security are preserved and properly handled during communication. It is like the "translator" that prepares data for network transmission and ensures it's ready for use upon receipt.

Presentation Layer

Have you ever opened a file on your computer that looked like random symbols? Why do you think that happens?

Claimed By:

Answer:

Presentation Layer

Part 2

Your browser displays unreadable text on a website. What could be causing this issue?

Claimed By:

Answer:

Application Layer

Presentation Layer

Session Layer

Transport Layer

Data-Link Layer

Network Layer

Physical Layer

You keep getting logged out of a website even though you signed in. Where might the problem lie?

Claimed By:

Answer:

Application Layer

Presentation Layer

Session Layer

Transport Layer

Data-Link Layer

Network Layer

Physical Layer

A fiber optic link between two offices is damaged. What are the consequences, and which layer is affected?

Claimed By:

Answer:

Application Layer

Presentation Layer

Session Layer

Transport Layer

Data-Link Layer

Network Layer

Physical Layer

In a crowded location with many devices connected to the same Wi-Fi network, users experience frequent disconnections and slow performance. Which layer of the OSI model is primarily responsible for this issue, and why?

Claimed By:

Answer:

Application Layer

Presentation Layer

Session Layer

Transport Layer

Data-Link Layer

Network Layer

Physical Layer

During a video call, sometimes the quality is poor with occasional glitches or delays, even when the connection remains stable. This happens because some packets are lost between the sender and receiver. Which layer is responsible for managing packet loss, and why might this issue occur during a video call?

Claimed By:

Answer:

Application Layer

Presentation Layer

Session Layer

Transport Layer

Data-Link Layer

Network Layer

Physical Layer

Explain why you are getting the error below and which layer deals with it?

Claimed By:

Answer:

Application Layer

Presentation Layer

Session Layer

Transport Layer

Data-Link Layer

Network Layer

Physical Layer

Your computer can access other devices on the same network, but it cannot connect to devices on a different network. Which layer of the OSI model is responsible for routing this traffic, and what might be the problem?

Claimed By:

Answer:

Application Layer

Presentation Layer

Session Layer

Transport Layer

Data-Link Layer

Network Layer

Physical Layer