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The benefits of using repeaters / Full-duplex transmitting

The benefits of using repeaters 
4.1.8 This page will explain how a repeater can be used to extend the distance of a LAN.
The distance that a LAN can cover is limited due to attenuation. Attenuation means that the signal weakens as it travels through the network. The resistance in the cable or medium through which the signal travels causes the loss of signal strength. An Ethernet repeater is a physical layer device on the network that boosts or regenerates the signal on an Ethernet LAN. When a repeater is used to extend the distance of a LAN, a single network can cover a greater distance and more users can share that same network. However, the use of repeaters and hubs adds to problems associated with broadcasts and collisions. It also has a negative effect on the overall performance of the shared media LAN. 
The Interactive Media Activity will teach students about the Cisco 1503 Micro Hub.
The next page will discuss full-duplex technology.

Full-duplex transmitting 
4.1.9 This page will explain how full-duplex Ethernet allows the transmission of a packet and the reception of a different packet at the same time. This simultaneous transmission and reception requires the use of two pairs of wires in the cable and a switched connection between each node. This connection is considered point-to-point and is collision free. Because both nodes can transmit and receive at the same time, there are no negotiations for bandwidth. Full-duplex Ethernet can use a cable infrastructure already in place, as long as the medium meets the minimum Ethernet standards.
To transmit and receive simultaneously, a dedicated switch port is required for each node. Full-duplex connections can use 10BASE-T, 100BASE-TX, or 100BASE-FX media to create point-to-point connections. The NICs on all connected devices must have full-duplex capabilities.
The full-duplex Ethernet switch takes advantage of the two pairs of wires in the cable and creates a direct connection between the transmit (TX) at one end of the circuit and the receive (RX) at the other end. With the two stations connected in this manner a collision free environment is created as the transmission and receipt of data occurs on separate non-competitive circuits.
Ethernet can usually only use 50 to 60 percent of the available 10 Mbps of bandwidth because of collisions and latency. Full-duplex Ethernet offers 100 percent of the bandwidth in both directions. This produces a potential 20 Mbps throughput, which results from 10 Mbps TX and 10 Mbps RX.
The Interactive Media Activity will help students learn the different characteristics of two full-duplex Ethernet standards.
This page concludes this lesson. The next lesson will introduce LAN switching. The first page describes LAN segmentation.

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