Average != Peak.
What is peak? There is a question for you. If we get all the way down to the fundamentals of any network, peak is always 100%. There is either a bit on the wire or not. Your network is either 100% busy or 100% idle at any instantaneous moment in time. What matters is average transfer rate to the user experience and even that varies a lot depending on the app in question and how that app tolerates things like jitter, loss, and latency. It is about whether data is being buffered waiting for a transmission window and is the buffer being cleared as fast as it is being filled. A network is engineered to support some average levels because it would be very cost ineffective to engineer a wide area network to support peak transmission on all ports at all times. All studies of network traffic show that it is not necessary to build a network that way. Our networks are statistical multiplexers in their design and have been all the way back to the Bell System. You do know that not everyone can make a phone call at once, right (but who would you call if everyone was already off hook, get it?)? In fact, it is such a difficult problem that it is very hard to support inside a single data center class Ethernet switch. In the wide area, it would be incredibly expensive to design an entirely non-blocking network at all traffic levels. It could be built if you want to pay for it however.
Why is this so hard to understand?
Mike
Steven Naslund Chicago IL