BJC Unit 4 Review (AP CSP - Internet)

Over July 13–16, 1863, rioters killed 100-1200 people, mostly black, and razed 50 buildings to the ground. Property damages are estimated at tens of millions of dollars in today's terms.

Two main grievances were that wealthier people could buy out of looming drafts for the Civil War, and fears that jobs would be taken by black Americans. Which city did this happen in?

• New York City

• Gettysburg

• Richmond

• Baltimore

• New Orleans

Answer explanation

Look up "New York City draft riots"

What best describes the protocols used on the Internet?

• they are designed and maintained by government agencies

• the protocols are different and depend on the manufacturer of the device

• the protocols are secret - no one knows how they work

• the protocols are open and used by all connected devices

Answer explanation

Anyone can write a program or create a device that can connect to the Internet, simply by following the public protocols to communicate.

T/F? In order to send a file over the Internet between 2 devices, there needs to be a direct connection b/t them.

• True

• False

• Depends

Answer explanation

False. Unlike landline telephones, which use a circuit-switched network where two phones/people talking to each other cannot talk to anyone else, the Internet uses a packet-based network where connections are temporary for transmitting small packets. Everything from a web page to a video is divided into thousands of packets to be sent via different routes and reassembled at the destination.

What is the MINIMUM number of paths that would need to be cut to prevent device G communicating with device A?

• 1

• 2

• 3

• 4

Answer explanation

Both devices A & G are connected to the rest of the network via 3 connections. Cut all three for one of them and they can't talk to each other.

When a message is sent from device B to device F, which of the following is true?

• The message will not get there

• The message could be routed using any possible path through nodes.

• It will always take the shortest path between the nodes

• The sender gets to decide the path the message will take

Answer explanation

This is the job of the IP layer. Things like "political" considerations (company policies, interconnection costs, etc.) will factor into routing.

ASCII standard for translating characters to binary code actually started out with 7 bits per character. This was quickly found to be insufficient so it was expanded to 8 bits, where it stayed. How many more characters did this improvement allow for?

• 1 more

• 1 time more (twice as many as before)

• 2 more

• 2 times more

• 2^8 times more

Answer explanation

Each additional bit doubles the number of items (like colors) that can be stored.

How many connections can fail before A & G cannot communicate?

• 3

• 8

• 10

• None of the above

Answer explanation

The shortest path is A-D-G. You can cut every other connection.

How does the Internet cope with increasing scale of continually added connected devices?

• Every year there are new Internet protocols that are developed

• The existing Internet protocols have been designed to scale

• Each connected device is responsible for updating the Internet protocols

• There really hasn't been that many more devices added

Answer explanation

The protocols are open so everyone can use them in their software or hardware. The Internet is a network of networks (Tech has a network, your home router creates a network, etc. They connect to an ISP like Verizon or Spectrum, which connects to other networks.), so you can connect to any subnetwork and access the wider Internet.

What best describes metadata for packets?

• It's part of the package that carries routing info and reassembling info

• There is no metadata with packets

• The metadata contains the content of the message

• It is the name of the process for hacking an Internet message

Answer explanation

Metadata is data about data. Metadata in packets may provide a checksum for the data transmitted to enable error checking or correction, origin & destination IP addresses, etc. They help with routing and integrity checks of the data in the packet.

T/F: Packets can arrive in any order.

• True

• False

• Depends

Answer explanation

Remember the analogy of shipping a space shuttle by using trucks to transport its parts?