Computer Networks
The Internet is a worldwide network containing millions of connected computers.
A Single Computer Meets a Worldwide Network
Imagine a computer that begins as a single device. Once it is connected to the Internet, it becomes part of a much larger network. The Internet is a worldwide network containing millions of connected computers, and the important idea is that computers throughout the world can belong to one huge network. This article follows that idea step by step: first how the network grows as new computers join, then how a connection is made, and finally what connected computers can do together.
Tracing How the Internet Grows
A useful way to follow the idea is to watch the network expand. Trace the state of the network through the steps below. The source notes that the network grows as new computers connect each day, and that this joining process happens continually.
- 1Starting state: many computers are already connected to the Internet, forming one worldwide network.
- 2A new computer connects. It does not create a different network; it becomes another participant in the same Internet.
- 3New state: the network now includes one more computer. The Internet is still the same network, only larger.
- 4The joining process continues. Each new connection repeats the same pattern, so the network keeps growing over time.
The newly connected computer does not replace or split the Internet. Joining the network adds a participant to it, and the network remains the same Internet.
Two Broad Ways to Join the Internet
Computers do not all have to use the same kind of connection. The source identifies two broad possibilities for joining the Internet: wireless communication and physical connection. Wireless communication links a computer without a physical cable between the computer and the network. Physical connection uses a physical link. Both are ways of reaching the same Internet.
The source also names three technologies used for physical connection: DSL, cable modems, and Ethernet. Each is an example of a technology a computer can use to connect to the Internet. A computer does not need to use the same one as every other computer in the network.
Separating the Internet from Its Connections
The source makes a useful separation between two questions. The first question is which network a computer has joined: the answer is the Internet. The second question is how the connection is made: the answer might be wireless communication, DSL, a cable modem, or Ethernet. The network is the structure; the connection technology is the access method.
What Makes Up a Computer Network
A computer network connects computers so they can communicate and share resources. The source describes three elements to keep in view: the connected computers, the communication that passes between them, and the shared resources that the connection makes available.
To explain a network clearly, describe both the connected computers and what they exchange or accomplish together. A list of machines alone does not describe a network; the communication and shared resources are what make the connection useful.
Ways Computers Exchange Information
Once computers are connected, they can exchange information in several forms. The source lists exchanging data and files, and sending or receiving messages, as forms of communication on a network. The same connection works in both directions: a computer can send information and receive information.
- Data: a computer on the network can exchange data with another computer on the same network.
- Files: a computer can exchange files with another computer on the same network.
- Messages: a computer can send a message to another computer and receive messages in return.
Following a Task Across Connected Computers
Connected computers can also cooperate on a large computation. The source calls this distributed computing on a network. Imagine a task that involves more than one computer. The important question is not only what each computer can do by itself, but whether the computers can exchange information and cooperate. The network is what makes that cooperation possible.
Splitting a large computation across three computers
A large computation is too big for one computer to finish quickly, so it is shared among three connected computers, A, B, and C. Describe how the work is split and how the results come back together.
- 1Identify the shared task
The large computation is the single task. No one computer is expected to do all of it alone.
- 2Divide the work
The task is split into three pieces. Computer A takes piece 1, computer B takes piece 2, and computer C takes piece 3.
- 3Compute in parallel on the network
Each computer works on its own piece while the others work on theirs. The computers cooperate because they are connected to one another.
- 4Return and combine the partial results
Each computer sends its partial result over the network, and the partial results are combined into the final answer.
The computation is completed through cooperation. Each computer contributes a partial result, and the network carries the information needed to combine them.
Communication Versus Cooperation on a Shared Computation
Two ideas are easy to blur. Communication means computers exchange data, files, or messages. Cooperation on a shared computation means several computers work together on one computation. A network enables both, but they are different activities. A pair of computers can exchange a message without doing any shared computation, and a shared computation can exist even when the computers mainly exchange partial results.
| Aspect | Communication | Cooperation on a shared computation |
|---|---|---|
| Main activity | Exchanging data, files, or messages | Working together on one large computation |
| Role of the network | Carries information between computers | Lets separate computers contribute to one task |
| Typical outcome | A computer receives information it needs | Partial results are combined into one result |
| Source term | Communication on a network | Distributed computing on a network |
Communication and cooperation are both enabled by a network, but they describe different activities.
Mistakes Learners Make About Networks
Common mistake Treating the connection technology as the Internet
What it looks likeSaying that DSL is the Internet because the computer uses DSL to get online.
Why it failsDSL, cable modems, and Ethernet are technologies used to connect a computer to the Internet. The Internet is the worldwide network the computer joins.
Do this insteadSay the computer connects to the Internet using DSL, not that DSL is the Internet.
Common mistake Thinking a computer must use the same connection as every other computer
What it looks likeAssuming that all computers on the Internet must use Ethernet.
Why it failsThe source states that computers do not all have to use the same kind of connection. Wireless communication and physical connection are both ways to join.
Do this insteadRecognize that different computers can join the same network through different connection methods.
Common mistake Describing a network only as a set of computers
Why it failsA network is defined by connected computers, communication between them, and shared resources. Without communication and shared resources, the description is incomplete.
Do this insteadDescribe both the connected computers and what they exchange or accomplish together.
Common mistake Confusing a new computer joining with a new network forming
What it looks likeBelieving that when one computer connects, a separate network is created.
Why it failsThe newly connected computer becomes another participant in the same Internet. The network is still the same Internet.
Do this insteadDescribe the join as the network growing, not as a new network appearing.
Practice: Classifying a Network Scenario
A home computer connects to the Internet using a cable modem. A second computer in another building connects using wireless communication. A third computer exchanges files with the second computer over the same network. For each situation, state whether it is about the Internet itself, a connection technology, communication, or cooperation on a shared computation. Then explain your reasoning in one sentence.
Hints
- Ask first whether the situation names the network or the way a computer reaches it.
- Exchanging files is communication, even though it happens over a network.
- Cooperation requires several computers working together on one shared computation, not just sending messages.
Key Takeaways
- The Internet is a worldwide network containing millions of connected computers, and it keeps growing as new computers join.
- A computer can join the Internet through wireless communication or physical connection; DSL, cable modems, and Ethernet are physical connection technologies named in the source.
- A computer network connects computers so they can communicate and share resources, exchanging data, files, and messages.
- Communication moves information between computers, while cooperation on a shared computation, called distributed computing, divides one task among connected computers.