TABLE OF CONTENTS In preceding chapters, we have examined the market drivers that are helping to make SONET and SDH critical technologies in the modern telecommunications marketplace; the underlying technological details that make them work; and the companies that manufacture products and use those products to create, manage, and maintain the modern global telecommunications network infrastructure. In this chapter, we turn our attention to the applications that take advantage of the network.
If we go back and revisit the chapter in which we discussed the drivers behind the success of both SONET and SDH, we find three common themes among all of them:
To meet the growing demand for bandwidth
To reduce the overall, aggregate cost for bit transport
To support the transport of differentiated services
We will examine each in turn.
Meet the growing demand for bandwidth: This stems from the inexorable growth in network-dependent applications that has been an ongoing phenomenon for more than 10 years. The global network has passed through a number of availability crises stemming from bandwidth demand outpacing bandwidth availability, but today that is less of a concern because of (1) the availability of in-place fiber, and (2) the capability to provision multiple channels over each fiber through the judicious deployment of DWDM. The answer then is to build higher capacity TDM systems, manufacture DWDM systems with higher channel counts, and ultimately enjoy systems with higher lambda counts per fiber, and higher bit rates per lambda. When this becomes...
