Communication Devices
Definitions:
‘Communication device’ is a piece of hardware that alls computers and any other devices to communicate.
‘Backbone’ refers to the physical layout and type of cables used.
Examples and Explanations:
Repeater – There is a limit to how far a signal can travel before it degenerates, after this distance the repeater Boosts or regenerates the signal. This allows the network to cover a much greater distance.
Hub – Allows sharing of a line or resource in a LAN. It is the converging point allowing the transfer of data between the devices. On the simplest level it duplicates the packets of data received via a single port, and makes them available for all the ports.
Bridge – Allows the joining of two LANs, if a LAN it is so large it may be more efficient to split it in to two separate LANs. This allows people to access both parts of the LAN but they mainly stay in their part.
Switch – Used instead of Hub or Bridge, The switch examines the incoming packets from the device and decides where it is intended to go. If the source and the destination on the network are on the same segment, it just simply filters that packet and stops it going on to any other segment of the network. If they are on different segments it simply forwards the packet on the desired segment. Since the packets are analysed by the switch it allows the bad packets to be filtered out so it saves on network traffic. The switch also builds a table of all the addresses giving them plug and play functionality.
Router – Used to connect two or more internet Protocol (IP) networks or and IP network to an internet connection. A router consists of a computer with at least two network cards supporting IP protocol. Receives packets via input network interface then chooses the appropriate output network interface.
Backbone – Ethernet cables, Token ring, Token bus, Fibre optic. Different examples of cables used in the systems.
