<<The Cerent box, apparently, can seemlessly groom all these traffic types for presentation to the Sonet transport layer.>>
Looking at the Cerent spec sheet, it appears to be a statistical multiplexer which allows different types of traffic (voice, data, video) to be stuffed down the same (very big) pipe.
If the pipe is big enough, then all of the packets will go through without any conflict and customers will be smiling.
I don't know about the economics of big pipes though. It would seem that a 2Gb pipe would cost twice what a 1Gb pipe costs on a per mile basis. If this cost is significant, then there is a benefit in prioritizing traffic down the pipe and charging more for the best QoS (a la ATM) rather than depending on IP 'best efforts' transmission.
Right now, massive fiber optic cables may mean there is an oversupply of fiber bandwidth - just waiting for someone to utilize it (I don't know). In the future though, Parkinson's Law will rule - traffic will increase to fill the pipes.
Quest's TV advertising -> do you want all of the movies ever made, in all languages, at any time, on your screen? If this was true for a large number of people, it would fill some very big pipes..
If the traffic approaches the size of the pipes, then some time, some packets will have to be tossed aside. With IP routing, those packets will just be retransmitted again (with a delay). This will cause lousy voice and video and will not reduce the average traffic (will actually increase the traffic). With ATM routing, connections with higher QoS can be differentiated and priced higher, and those packets will not be tossed aside.
The future (ATM vs IP) depends on the ultimate cost per mile of a Gb of fiber cable bandwidth versus the capital cost of the equipment to feed the cable and keep track of the packets and manage things through thick and thin (cable breakage, power failures, software upgrades, etc.) |
