What Is a Computer Network?

If you had to connect the computers for two or more employees in the same office, you would need a computer network. In its simplest form, a network consists of two or more connected computers. Figure 7.1 illustrates the major hardware, software, and transmission components in a simple network: a cli­ent computer and a dedicated server computer, network interfaces, a con­nection medium, network operating system software, and either a hub or a switch.

Each computer on the network contains a network interface device to link the computer to the network. The connection medium for linking network components can be a telephone wire, coaxial cable, or radio signal in the case of cell phone and wireless local area networks (Wi-Fi networks).

The network operating system (NOS) routes and manages communica­tions on the network and coordinates network resources. It can reside on every computer in the network or primarily on a dedicated server computer for all the applications on the network. A server is a computer on a network that per­forms important network functions for client computers, such as displaying web pages, storing data, and storing the network operating system (hence con­trolling the network). Microsoft Windows Server and Linux are the most widely used network operating systems.

Most networks also contain a switch or a hub acting as a connection point between the computers. Hubs are simple devices that connect network com­ponents, sending a packet of data to all other connected devices. A switch has more intelligence than a hub and can filter and forward data to a specified des­tination on the network.

What if you want to communicate with another network, such as the Internet? You would need a router. A router is a communications processor that routes packets of data through different networks, ensuring that the data sent get to the correct address.

Network switches and routers have proprietary software built into their hardware for directing the movement of data on the network. This can cre­ate network bottlenecks and makes the process of configuring a network more complicated and time-consuming. Software-defined networking (SDN) is a networking approach in which many of these control functions are managed by one central program, which can run on inexpensive commodity servers that are separate from the network devices themselves. This is especially helpful in a cloud computing environment with many pieces of hardware because it allows a network administrator to manage traffic loads in a flexible and more efficient manner.

Networks in Large Companies

The network we’ve just described might be suitable for a small business, but what about large companies with many locations and thousands of employees? As a firm grows, its small networks can be tied together into a corporate-wide networking infrastructure. The network infrastructure for a large corporation consists of a large number of these small local area networks linked to other local area networks and to firmwide corporate networks. A number of power­ful servers support a corporate website, a corporate intranet, and perhaps an extranet. Some of these servers link to other large computers supporting back­end systems.

Figure 7.2 provides an illustration of these more-complex, larger-scale corporate-wide networks. Here the corporate network infrastructure supports a mobile sales force using mobile phones and smartphones, mobile employees linking to the company website, and internal company networks using mobile wireless local area networks (Wi-Fi networks). In addition to these computer networks, the firm’s infrastructure may include a separate telephone network that handles most voice data. Many firms are dispensing with their traditional telephone networks and using Internet telephones that run on their existing data networks (described later).

As you can see from this figure, a large corporate network infrastructure uses a wide variety of technologies—everything from ordinary telephone service and corporate data networks to Internet service, wireless Internet, and mobile phones. One of the major problems facing corporations today is how to inte­grate all the different communication networks and channels into a coherent system that enables information to flow from one part of the corporation to another and from one system to another.

Source: Laudon Kenneth C., Laudon Jane Price (2020), Management Information Systems: Managing the Digital Firm, Pearson; 16th edition.

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