Network Performance

• The following are two popular laws that predict the advances in network technologies.
  1. Gilder's Law; George Gilder projected that the total bandwidth of communication systems triples every 12 months.
  2. Metcalfe's Law; Robert Metcalfe projected that the value of a network is proportional to the square of the number of nodes.
• Gilder's law tells us that networking speed is increasing faster than processing power. While this remains true for the backbone network, end-to-end performance is likely to be limited by bottlenecks. For example, over about 15 years, LAN technology has increased in speed from 10 Megabits per second (10 Mbps) to 10 Giga-bits per second (10 Gbps), which is a factor of 1000 increase. Over a similar time period, advances in silicon technology, driven by Moore's Law, have allowed the CPU clock frequency in an average PC to increase from roughly 25 MHz to 2.5 GHz (a factor of about 100 increase in processing power).
• Metcalfe's law also explains the prolific growth of the Internet. As a network grows, the value of being connected to it grows exponentially, while the cost per user remains the same or even reduces.