TABLE OF CONTENTS Before we descend into the technological depths of the SONET frame structure, let s revisit the purpose for SONET in the first place. Remember that the digital hierarchy (DS-0, DS-1, DS-2, DS-3, and so on) was created to provide cost-effective multiplexed transport for voice and data traffic from one location in a network to another. SONET has the same responsibility, albeit on a larger scale: indeed, it is sometimes described as T-1 on steroids.
SONET brings with it a subset of advantages that makes it stand above competitive technologies. These include mid-span meet, improved operations, administration, maintenance, and provisioning (OAM&P), support for multipoint circuit configurations, non-intrusive facility monitoring, and the ability to deploy a variety of new services. We will examine each of these in the following sections.
When Bill McGowan first complained about the fact that Equal Access required him to ultimately spend MCI s money on AT&T hardware, he was complaining about the lack of a mid-span meet ability in other words, the ability of one vendor s optical multiplexer to not only connect electrically with that of another vendor, but to actually pass understandable maintenance messages between the two. Because of the monopoly nature of early networks, interoperability was a laughable dream. Following the divestiture of AT&T, however, and the realization of Equal Access, the need for interoperability standards became a matter of some priority. Mid-span meet was SONET s contribution to this important effort.
Improved OAM&P is without question one of the greatest contributions that...
