Copy from Review for Federal Government, Winter 1994-95, pg 13, 620 words

"If you build it, they will come," so Kevin Costner’s character built a baseball field in he Iowa cornfields of a Hollywood movie.

And in real life, U S WEST built Synchronous Service Transport.

"SST is the gateway to the information highway," said U S WEST Product Manager John Schenk. "Customers often tell us what they want from us. And whenever we introduce faster speeds, they come to us with new ideas and applications for the service."

Basically, SST is a linear SONET (Synchronous Optical Network) two-point private line that operates at OC-3, OC-12 and OC-48 speeds — 155.52 MBPs, 622.08 MBPS and 2,488 Gbps respectively — with Add-Drop Multiplexing (ADM) functionality at the serving wire centers.

Twenty years ago, 150 bps teletypewriters were state-of-the art. Ten years later, DS1 was. With offerings at 2,488 Gbps, SST is over two million times faster than the teletypewriter and 1600 times faster than DS!. If the past is any indicator, SST will double in capacity every two years.

SST fiber and optical transmission media is re0placing both the copper plant and digital formats — and it is a major step toward the error-free network.

Mechanically, the entire optical system is protected by redundancy. Each piece of network equipment has a working laser and receiver, in addition to a protect laser and receiver system that will take over automatically is there is a failure on the working system. The transfer takes less than 50 milliseconds. There is a corresponding physical redundancy in the loops between U S WEST wire centers and customer premises.

The protect laser fiber pair is routed 25 feet or more away from the working fiber pair. This diversity is from the first utility vault outside the wire center to the last terminal before the subscriber.

SONET technology contains several monitoring levels and the entire system is monitored at the Synchronous Transport Signal (STS) level the local maintenance center. This ‘performance monitoring’ examines the quality of the data being transmitted. 1.73 megabits of data are dedicated to maintenance and quality monitoring in each STS. There are three STSs in each OC-3.

U S WEST monitors the occasional errors that occur in all systems, and searches for recurrences that might indicate system degradation. Over 19 parameters are constantly checked. Some — like Code Violation — are monitored at the section, line, STS path, and virtual tributary path levels. If any violation occurs six or more times in an eight-hour period, an alarm is sent to the maintenance center for possible corrective action. These errors are normally invisible to end-users, and careful monitoring prevents them from becoming visible.

The overall message is monitored via a path overhead that is embedded in the payload delivered to the subscriber. This is available to the subscriber for monitoring the quality of the message envelope.

An excellent example of SST technology deployment is the design of Boeing’s newest commercial airplane, the 777. By using SST in their computer-aided design process, they were able to significantly reduce the design and delivery time of the final product. The technology also helped Boeing improve the quality of the air-frame-product design.

As the country takes its first tentative steps on the information highway, the direction we’ll go next is still a mystery. Applications are devised daily by U S WEST customers that improve the way we all communicate and do business. SST is the transportation vehicle that will deliver these applications to the nation.