AP CSP Unit 2 Test Review (Part 2)

How is information sent across the internet?

1) Information is broken down into packets, or tiny chunks of data.

2) Each packet is sent to a different router that finds the best path for the packet to travel.

3) Once all the packets reach their destination, they reassemble.

Why do Internet Networks have multiple paths?

To ensure that data is traveled as quickly, efficiently, and safely as possible while avoiding faulty paths.

Fault Tolerant

Ensures that a system or network keeps working even if part of it fails by finding other ways to operate.

Do networks implement Fault Tolerance?

Yes, it allows for data to get sent to its intended destination even if some paths may not work.

Redundancy

Adding extra components to make sure a system continues to work even if parts of it fail.

How is Redundancy implemented in the Internet?

There are multiple paths between networks and routers that data can travel on, and many important companies/services have multiple DNS servers in many different locations.

Router

A type of special computer that forwards data across a network by choosing the best path based on speed, congestion, relationships between companies, etc.

Packet

A chunk of data sent over a network.

Do packets arrive at their destination in the exact same time and order?

No, it varies slightly.

What does the Transmission Control Protocol (TCP) do?

It manages the sending and receiving of all data as packets by scanning the packets you receive and ensures everything has arrived.

What happens if the sender doesn't send all the packets?

It keeps sending packets until the TCP verifies that all packets have arrived.

Are TCP & Routers scalable? What about DNS & Internet Protocols?

Yes, all of them are scalable.

Web Browser

The application you use to access web pages.

URL (Uniform Resource Locator)

The link of the website you want to visit.

What happens after you type in a URL into your browser and then press enter?

1) Your computer communicates with a DNS server to get the IP Address of the website.

2) The computer then uses the IP address of the website to talk to its web server, sending a GET Request asking for the website’s data.

3) The web server sends the website data back to the computer using HTTP (a protocol, not a language).

GET Requests

A HTTP request sent by a computer to a web server to ask for a webpage’s data.

HTTP (HyperText Transfer Protocol)

The protocol used for communication between a computer and a web-server (computer uses GET Requests).

How is a website page loaded?

The web-server returns data using the HTTP protocol in HTML, a language that tells the web-browser how the website’s supposed to look.

What are HTTP requests?

Message sent from browser to web-server using HTTP protocol.

ex: GET requests & POST requests

What website element (ie. text, image) is included in HTML, and which elements require additional HTTP requests?

The website’s text is included in the HTML language, but the computer needs to send more HTTP requests to get images and videos.

What type of request is sent after you type information into a website (ex: logging in, filling out an online form)?

HTTP POST request

What are Cookies?

An ID number that identifies you so that the next time you visit the same website, the browser sends a cookie with its web-server request, and the server will send back the data knowing you’re visiting the website again.

How do safe websites prevent hackers from snooping in on personal information sent over the internet?

They use a Secure Sockets Layer (SSL) and Transport Layer Security (TLS), which collectively act as a layer of security around communications that protect your data from being spied on.

What is the visual indicator for the SSL and TLS on the web-broswer?

A tiny lock symbol next to the ‘https://’ domain name.

What is HTTPS and how is it different from HTTP?

It’s a protocol similar to HTTP, but the difference is that HTTPS encrypts data so it can’t be easily read or tampered with by anyone else.

What are Digital Certificates?

Certificates provided by a Certificate Authority that verifies the identities of websites and ensures they’re legit.

What are the 3 layers of how information travels across the internet, from top to bottom?

1) HTTP & DNS - Manages sending/receiving of web files and websites.

2) TCP/UDP, IP, & Routing - Breaks information down into packets for travel and ensure they arrive correctly.

3) Wires, Cables, & WiFi - Physically transmits binary sequences that make up packets.

Datastream

 A continuous flow of data sent or received over a network.

Net Neutrality

The idea that all internet traffic should be treated equally by ISPs.

IP

A set of rules that control how data is sent and received over the internet.

Scalability

The ability of a system to grow and handle more work & users without breaking or slowing down.

Digital Divide

Refers to the gap between people who have access to technology & the internet versus those who do not, primarily due to income, location, education, or resources.

UDP

A communication protocol like TCP but differs in that it just sends data quickly without checking for errors or confirming if the data arrived at its destination.

Packet Metadata

Extra info added to each data packet that helps it get to the right place across the internet, and every packet must have metadata.

What are the 4 components of Packet Metadata?

1) Source Address (sender’s IP)

2) Destination Address (reciever’s IP)

3) Packet # to help with correct reassembly of packets

4) If it uses TCP or UDP protocols.

What is the difference between the Internet and the World Wide Web?

The internet broadly refers to the global network of computers, while the World Wide Web refers to the website and pages that you access over the internet using a web browser.

Internet Censorship

When governments, organizations, or companies restrict or control what people can see or do online.

What are Octets in an IP Address?

• They are each individual # in an IP address separated by dots.

• The first 3 octets are used to determine the network your device is in, while the last octet determines your specific device in the network.

Circuit Switching

A dedicated path between the sender and receiver where data travels continuously along the path, it’s reliable and provides consistent speed but it's also inefficient because no one else can use the path.

Packet Switching

When data is broken down into packets and travels through different paths to reach the destination, where the packets then reassemble into order once all the packets have arrived.