Overview

In the last two years, the metropolitan region of the global telecommunications network has come into its own. Once a tiny, almost inconsequential segment that many characterized as experimental, metro has now become a serious moneymaking contender. A number of factors account for its ascendancy, including changes in the demographic structure of corporations; evolutionary shifts in workflow; the increasing importance of data, information, and knowledge management; and the related importance of database access, changes in network topologies, the rise of Ethernet bandwidth, and the bandwidth discrepancy that exists between the glutted core and the hungry edge. Another key factor is convergence and the evolution of the multiservice network, the greatest use of which appears to be in the metro domain.

There was a time when corporate headquarters was exactly that a single, monolithic building that housed a corporation s employees. Today that environment is evolving such that multiple corporate locations within a metro area are the norm as companies place staff close to major customer clusters. This shift in real estate philosophy, however, brings with it an additional challenge: the need to be interconnected. Furthermore, the network that interconnects these corporate facilities must support a broad range of applications and must satisfy all of their far-ranging quality of service (QoS) requirements.

A metropolitan network has the following characteristics. It is found at the edge of the high-bandwidth core network and usually directly touches users as well as the core transport network, serving in effect as the interface point between two...