Higher Computing

Hubs, Switches and Routers

Whatever type of transmission medium or topology is chosen for a network, there must be some means of connecting the workstations

Hubs, switches and router are all devices which allow workstations to be connected and so create a network topology

Hub

  • A hub has multiple port, allowing more than one device to share the same wire
  • A hub is a shared device - only one station 'speaks' at a time
  • A hub receives a signal and then amplifies the signal so that all stations connected to the hub receive it, even if it isn't meant for them
  • A hub could be considered a 'dumb' device


Switches

  • A switch divides a network into separate segments, one segment for each sonnected machine
  • More than one machine can speak at once and only the intened recipients receive the data siganl
  • Records the IP and MAC addresses in a table of all the devices connected to it
  • Workstations which are connected via a switch benefit because there are no collisions between signals to reduce the speed of the network
  • A switch could be considered a 'little bit smarter' than a hub


Router

  • Connects two or more smaller networks into larger internetworks
  • The router looks at the destination address of the packets of data passing through it, and decides which route each packet should take
  • A router could be the 'smartest device' of the three


Advances in Computer Hardware

Processors

Faster, increased number of processors on a single chip in one computer


Main Memory Capacity

Increased RAM chips due to falling costs


Backing Storage

Increased hard disk storage due to falling costs and introduction of new media, such as Blu-ray


Data Transfer Rates

Increasing from 10Mbps Ethernet to 100 Mbps and will replace by 1000 Mbps