Repeaters

Repeaters

A repeater is a network device that repeats a signal from one port onto the other ports to which it is connected (see Figure 2.10). 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.

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 inter preted. 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 (see Chapter 13, “Troubleshooting,” for details).

The primary purpose of a repeater is to enable the network to expand beyond the distance limitations of the transmission medium (see Chapter 3 for more details).

The advantages of repeaters are that they are inexpensive and simple. In addition, though they cannot connect networks with dissimilar data frames (such as a Token Ring network to an Ethernet network), some repeaters can connect segments with similar frame types but dissimilar cabling.