4.1 The Internet

Enduring Understanding

Computer systems and networks facilitate the transfer of data.

Learning Objective

Explain how computing devices work together in a network.

Essential Knowledge

A computing device is a physical artifact that can run a program. Some examples include computers, tablets, servers, routers, and smart sensors.

A computing system is a group of computing devices and programs working together for a common purpose.

A computer network is a group of interconnected computing devices capable of sending or receiving data.

A computer network is a type of computing system.

A path between two computing devices on a computer network (a sender and a receiver) is a sequence of directly connected computing devices that begins at the sender and ends at the receiver.

Routing is the process of finding a path from sender to receiver.

The bandwidth of a computer network is the maximum amount of data that can be sent in a fixed amount of time.

Bandwidth is usually measured in bits per second.

Learning Objective

Explain how the Internet works.

Essential Knowledge

The Internet is a computer network consisting of interconnected networks that use standardized, open (nonproprietary) communication protocols.

Access to the Internet depends on the ability to connect a computing device to an Internet connected device.

A protocol is an agreed-upon set of rules that specify the behavior of a system.

The protocols used in the Internet are open, which allows users to easily connect additional computing devices to the Internet.

Routing on the Internet is usually dynamic; it is not specified in advance.

The scalability of a system is the capacity for the system to change in size and scale to meet new demands.

The Internet was designed to be scalable.

Learning Objective

Explain how data are sent through the Internet via packets

Essential Knowledge

Information is passed through the Internet as a data stream. Data streams contain chunks of data, which are encapsulated in packets.

Packets contain a chunk of data and metadata used for routing the packet between the origin and the destination on the Internet, as well as for data reassembly.

Packets may arrive at the destination in order, out of order, or not at all.

IP, TCP, and UDP are common protocols used on the Internet.

Learning Objective

Describe the differences between the Internet and the World Wide Web.

Essential Knowledge

The World Wide Web is a system of linked pages, programs, and files.

HTTP is a protocol used by the World Wide Web.

The World Wide Web uses the Internet