Systems should be as simple as possible but not simpler Albert Einstein
Many people are familiar with the ﬁrst widely used service of the datacomms era—X.25. As a mature product of the ‘analogue era’, it is a complex protocol. Much of this complexity arose from the need to protect against errors introduced by noisy analogue transmission circuits and the comparatively long round-trip delay caused by their low transmission speeds. Frame Relay, by contrast, is very much a product of the ‘digital age’, exploiting the much lower error rates and higher transmission speeds of modern digital systems. In particular, Frame Relay...