LAN Switches – root switch congestion
Look at this network architecture. Consider each LAN switch in turn and imagine a computer connected to one of its ports. Now starting from this computer, trace a route through the network to the other switches. If you complete this exercise for the whole network then you will find that more routes and hence, more traffic passes through switch R than any other switch.
The switch that has most routes passing through it – switch R in this case – is called the root switch (note the different spelling). As the network grows in terms of the number of connected users and the amount of data they send, so ever more traffic must pass through the root switch and it will become more and more congested. Many switches now provide ‘back pressure’ to control congestion. This effectively forces a block on the port to prevent transmission.