A network device allows a computer to communicate to another computer to either give information and/or to receive information or services (within a Local Area Network or into other networks via the “Cloud”).
Understanding what the different network devices are and normally used for will help when working with them. I will list the more commons types and explain their role in getting this communication job done. The first is a Hub.
This device lives on the OSI model’s first level. It is like driving with bumper cars. There seems to be little guidelines on how traffic flows and allows for collisions to happen frequently (which slows or kill the person “data”). It runs on a half duplex (like on a walkie talkie where one party talks and says “over” and then the other side starts to talk… back and forth. In a small home/office environment, this device can allow some computers to get by without too much of an issue, but when there are many hubs being used, then the communication starts to breakdown and cause bottlenecks. Hubs are in a way considered passive and dumb (not much intelligence in it). A cousin of the hub is a Repeater which is similar to the HUB except it is active in providing an extra boost to push the data to the next contact point and is usually after a Hub or Switch.
This device lives on the OSI model’s second level. It is like your home car. You get in it and follow rules of driving to navigate from one point to another. This device has more advantages to the Hub because each port is its own direct line to another location, avoids common collisions, and communicates at Full-duplex (similar to phones where each end can talk and/or be heard and not needing to wait for a pause to continue). These devices have built in logic that uses M.A.C. (Media Access Control, a unique identifiers also known as hardware or physical address) to know where to find others on the
same network after an initial broadcast the first time around.
This device lives on the OSI model’s third level. It is like leaving home in your car from your main street and hitting a highway. One semi-major road that can lead you to larger expressways or through several other
streets depending on where you need to go. It uses an IP (Internet Protocol) Address and matches a computer’s MAC address to this IP address to help find or deliver to those computers. This device can be pretty complex in its logic. It has security features, can have governing rules for either parties within the network or regarding those from without trying to get in. Typically this device allows a network to each the internet and is sometimes referred to as a Gateway. This device (when acting as a Gateway) will normally connect to a modem that belongs to an ISP (Internet Service Provider) who gets us on to the WAN, the “Cloud” also known as the Internet.
Wireless LAN Controller
This device also lives on the OSI model’s third level. It is used to manage WAPs (Wireless Access Points) that bridge out or allow wireless connection to the network and works with the network Router to assist it to get the data to the right location.