Communication Devices and OSI Model

TIP: Until you have not read my article "The OSI Reference Model", you will not be able to understand most of the terminology written beneath this tip.

Each of the three lowest levels of the OSI model supports an important part network hardware device. See, you remember not. What are three OSI layers, down from the cable? Layers are; Physical Layer, Data Link Layer, and Network Layer. Anyway, back to article. The function of these devices (and the differences between them) sheds some light on the functions of their corresponding OSI layers. This article shows very briefly how the following devices fit within the OSI model:

1. Repeaters (Operate at the OSI Physical Layer).
2. Bridges (Operate at the OSI Data Link Layer).
3. Routers {and Brouters} (Operate at the OSI Network Layer).

These devices will be discussed in detail individually in my incoming articles. By the time, this is an introductory article.

Repeaters

A 'Repeater' is a network device that repeats a signal from one port onto the other ports to which it is connected. Repeaters operate at the OSI Physical layer. A repeater does not filter or interpret anything; instead, it merely repeats (regenerates) a signal, passing all network traffic in all directions. Yes! It also passes the 'Electrical Storms' generated by huge amount of computers, wires, or any other source. Not only that, it boosts up the already-boosted storms making nasty circumstances for other segments on the local area or extended local area networks (LANs and Extended LANs). Anyway, a repeater can operate at the OSI Physical layer because a repeater doesn't require any addressing information from the data frame. Therefore, the repeater doesn't have to pass the frame to upper layers where addresses and other parameters are interpreted. A repeater merely passes along bits of data, even if a data frame is corrupt. In fact, a repeater even will forward a broadcast storm caused by a malfunctioning adapter. The primary purpose of a repeater is to enable the network to expand beyond the distance limitations of the transmission medium.

Advantages:

The advantages of repeaters are that they are inexpensive and simple. In

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