What is a Computer Network?

What is a Computer Network?

A computer network is a system of interconnected computer nodes that can communicate with each other. It normally takes at least three nodes for the system to be considered a network. Sometimes a small network that is part of a larger network is called a “sub-network.” The connection between two nodes is called a “network link.” Here are more details on the characteristics and functions of a computer network.

Why Computer Networks Exist

Computer networks began with experimentations among government scientists working for the Defense Department. Once the first internet connections began with UCLA, Stanford, UC Santa Barbara and University of Utah in 1969, the concept began to develop as an educational tool among universities. By the late seventies, computer networks were embraced by many businesses that used the systems to organize and automate transactions and marketing. Today computer networks are used by nearly all businesses and government institutions to help reduce costs involved with communication or generating and storing data.

Network Size

Connecting four home computers forms a Local Area Network (LAN). Usually any network in which every node is within walking distance is known as a LAN regardless of the number of computers that can access it. A more robust network spread over a wider geographic area is often referred to as a Wide Area Network (WAN). A network with nodes all over the world is an example of a WAN. The main two network categories in terms of function are peer-to-peer and server-based. A peer-to-peer network commonly found in a cyber cafe uses a number of workstations instead of dedicated servers as a way to cut costs. A server-based network, however, stores resources to be shared on one computer, providing a central location where data must be backed up.

What is a Computer Network?

Shape of the Network

When the network is illustrated with images that depict how nodes are linked, the diagram forms a topology that can be identified and analyzed. Small networks tend to be linear whereas enterprise networks usually comprise both clients and servers that form various shapes and sub-networks connected to a common backbone.

The most widespread topology today is called a “collapsed ring,” in which the central node acts as a hub while the end nodes and the rest of the network are connected with one cable. A “star topology” is also widely used, in which a central note connects to each workstation through a cable. While star topography involves excessive cabling, it is strong in the sense that the network still functions properly if a single connection fails. Another common shape that requires less cabling is “bus topology,” in which a single cable connects each node in the network and data runs through all nodes.


Many of the components of a computer network are visible to the common user, such as PCs, laptops and smartphones. These devices communicate with IP routers, ethernet connections, as well as wireless links. Nodes on a network can serve as host servers or clients. The purpose of business networks is often to provide access to applications that allow for team collaboration or communication on a project. While hosts, routers and cables comprise the hardware, protocols and applications are the basis of the software element. Some companies consider their service agents to be part of their computer network.

A small network can be connected to larger networks through modems or wireless routers. The advent of broadband technology has made voice-over-IP (VoIP) a combination of voice and data delivered over the internet, lowering the cost of phone communication. As broadband technology improves, networks may have require less components. At one time bandwidth was a factor in measuring the strength of a computer network, but now high speed internet has become a widely adopted standard.

While the term “host” is commonly thought of as an internet service provider (ISP), it can refer to any node on a network that sends or receives information. A host can be a server or a workstation, as well as a router, printer or any other device on the network. Servers usually are differentiated from workstations because they typically contain special software, along with more disk space and memory. A workstation is usually called a client and typically runs a widely used operating system such as Windows.

Protocols That Define Communication

A protocol is the set of platform rules that define computer network communication. When modems talk to each other over a phone line, they need to use the same protocol that determines the language that is communicated. There are now many different protocols, although modern modems are designed to try multiple protocols before finding one that can be understood at both ends. Some of the different types of protocols include IP, TCP, CSMA/CD and CSMA/CA.

Network Design

Networks can be customized to fit any business culture. The most important characteristics of a network design include availability, cost, reliability, security and speed. Scalability and topography are concerns for more complex and growing businesses. Availability deals with the amount of minutes a network is available in a year, which produces a percentage, ideally close to 100 percent. Costs are determined by how network components are installed and how often they require maintenance. Reliability is reflected in the quality of connectivity. Security is whatever software it takes to protect data, whether stored or transmitted. Speed is measured by data rate or how fast data can be transmitted from one node to another.

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