What are network devices?

Network devices are components used to connect computers or other electronic devices so that they can share files or resources such as printers or fax machines. Devices used to set up a local area network (LAN) are the most common types of network devices used by the public. A LAN requires a hub, router, cabling or radio technology, network cards, and, if online access is desired, a high-speed modem. Fortunately, this is a lot less complicated than it might seem to someone new to networking.

A router, a type of wireless networking device.

In a network, one computer is designated as a server and the others as clients. The server is connected to an external hub, to which the clients are also connected. Now that each computer has a foot in a common electronics port (the hub), they can use the hub to pass signals back and forth. To direct these signals, the hub contains a device known as a router. The router is the equivalent of an electronic traffic guard that controls data traffic between computers.

A DSL filter.

Sounds good, but how does the router distinguish one computer from another? The answer is that all computers on the network must have a network card installed. Each of these network devices contains a unique address. In a wired network, special cabling called Ethernet runs from the NIC to the hub. In a wireless network, the NICs and the router/hub communicate using radio waves.

An Ethernet cable.

Network cards identify themselves on the network, sending all requests to the router with the unique return address included. The router reads the “To” address and the “From” address and forwards traffic accordingly. In other types of network, all requests made on the local network are broadcast by the router to all machines on the network, but only the machine with the corresponding address responds, however, this is not so secure because other machines can intercept the traffic that is not addressed to them.

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A wireless router can be used to set up a local area network.

Online access is optional on a local network, but if included, a single online account can be shared by all computers on the network. When online access is available, the router not only directs traffic on the local network, but also handles requests made to the Internet and subsequent responses. The router acts as a gateway to the Internet and also acts as a hardware firewall to prevent unsolicited traffic from returning to the network.

One can add online access to a LAN by connecting a router/hub to a high-speed modem, or by purchasing a high-speed modem that has a built-in router/hub. The high-speed modem must support the online service. Most modems are specifically designed for use with DSL, cable, or fiber optics, although some models can be made to work with more than one technology, such as DSL and cable-compatible.

When setting up a LAN, all network devices must be compatible. If building a wired LAN using Ethernet cabling, NICs will be designed with an Ethernet port. If building a wireless LAN, all network devices must not only be designed for wireless use, but must speak the same wireless language or protocol. As of spring 2009, the fastest and most current protocol available is 802.11n, while the oldest protocol still in widespread use is 802.11g. The router/modem and network cards must support the same protocol to communicate with each other.

Wireless network devices can also carry Wi-Fi® certification, guaranteed to be fully compliant with the standards or protocol(s) that the product supports. Wi-Fi certification comes from the Wi-Fi Alliance, the organization responsible for developing wireless protocols. Many wireless network devices are marketed as being compatible with one or more protocols, but lack certification. The guarantee might be an important consideration when setting up a business LAN, but it probably isn’t a concern for home LANs.

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A wired network router.

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