Code.org Unit 2

Which of the following best describes the protocols used on the Internet?

• The protocols of the Internet are secret to maintain the privacy and security of people using them

• The protocols of the Internet are designed by government agencies to ensure they remain free to us

• The protocols of the Internet are open and used by all devices connected to the network

Answer explanation

One of the most important ideas behind protocols is the idea that they agreed upon by everyone using a given system, in this case the internet.

Juan purchases a new smartphone and is immediately able to use it to send a photo over the Internet to a friend who lives in a different country. Which of the following is NOT necessary to make this possible?

• Both devices are directly connected to at least one part of the Internet

• The data of the image is routed through a sequence of directly connected devices before arriving at its destination.

• A single direct connection is established between any two devices connected to the Internet

Answer explanation

A path between two devices connected to the internet is a sequence of directly connected devices, not one single direct connection.

Which of the following is true of how the Internet has responded to the increasing number of devices now using the network?

• The Internet protocols are changed every year to adapt to the new devices that have been connected to the network

• The protocols of the Internet are no longer necessary thanks to the large number of devices now connected to the network

• The protocols of the Internet were designed to scale as new devices are added

Answer explanation

These protocols improve the reliability of sending and receiving data no matter how many devices are connected to the network

7.

Which of the following is true of how packets are sent through the Internet?

• Packet metadata is only included on important packets to indicate they should get access to faster paths through the network

• Information sent through the internet is split into two packets, one which contains the message and another which contains the metadata

• Packet metadata is used to route and reassemble information travelling through the Internet

Answer explanation

The metadata for a packet includes information about where it came from, where it's going, and how it fits in with the rest of the packets it's associated with.

Eva is watching an online video. The video is being sent to her laptop by a server over the Internet which splits the video into packets and sends them in the order they appear in the video. Which of the following is true about how the packets will arrive at her computer?

• The packets may arrive out of order

• Either every packet will reach her computer or none of them will.

• Packets that arrive out of order will be sent back to the server.

Answer explanation

Because each of the packets may take different routes to Emilee's computer and these routes may be slower or faster compared with the others, the packets may arrive in a different order from how they were sent.

Which of the following best describes the purpose of an IP address?

• IP addresses indicate how many times an individual packet has been requested by a router

• IP addresses provide a unique number for identifying devices that send and receive information on the Internet

Answer explanation

IP addresses are similar to phone numbers or street addresses in that each device has a unique one and knowing this address will allow you to send a message to that location.

Which of the following Internet protocols is MOST important in reassembling packets and requesting missing packets to form complete messages?

• Internet Protocol (IP)

• Transmission Control Protocol (TCP)

• User Datagram Protocol (UDP)

Answer explanation

While both TCP and UDP both involve the sending and receiving of packets, TCP is the protocol used when the accuracy or completeness of a message is a priority.

Which of the following Internet protocols is used to request and send pages and files on the World Wide Web?

• Internet Protocol (IP)

• User Datagram Protocol (UDP)

• HyperText Transfer Protocol (HTTP)

Two devices are connected to the Internet and communicating with one another. A squirrel chews through one of the wires in the network that is currently being used by the devices to communicate. The network immediately begins using a different path through the network and communication continues as normal.   This situation best exemplifies which principle?

• pathing

•   fault-tolerance

• scalability

Answer explanation

Building networks with redundancy, multiple paths between any two connected devices, allows for them to be fault tolerant and in this case when the squirrel chews through one of the wires, the network can use one of the other paths that connects these two devices.

An Internet Service Provider (ISP) is a company that builds the routers and wired connections that allow individuals to access the Internet.   An ISP is considering adding additional redundant connections to its network. Which of the following best describes why the company would choose to do so?

• It costs less to design a network that is redundant

• Redundant networks are more reliable

• Adding additional connections reduces the fault-tolerance of the network

Answer explanation

When a network contains redundant connections, the network can continue to function in the event of slow downs or disconnections in specific parts of the network.