George D. Miller
Group Editorial Director
Few standards are as germane to the continuing development of fiber optics technology as the synchronous optical network. Currently estimated to be 90% complete (see Special Report, page 37), this standard is already driving the convergence of the telecommunications, data communications and video markets; the transport and switching functions of networks; the formerly distinct narrowband, wideband and broadband service classes; and even wide- and local area network technologies.
To be sure, compared to other communications standards, Sonet has enjoyed a relatively smooth development during its 11 years; but that could be a result of proper timing in making the transition from an asynchronous fiber transport medium to a synchronous one. This is not to imply the development of Sonet has been without difficulty; rather, those difficulties have been well-managed.
But like climbing any mountain, the last 10% of the Sonet standard`s climb will likely be the most difficult. The true promise of Sonet--the much sought after mid-span meet and the capability of end-to-end management of networks comprising equipment from different manufacturers--implies a surrendering of control (and perhaps market share) that would cause even the most progressive manufacturer to wince. And for the service providers, whether their roots are in telecommunications, data communications or cable TV, Sonet presents unmatched network management capabilities and unmatched network management challenges: Where will the service providers find the software and other technical expertise that can harness the power of Sonet?
Of course, the last 10% of the Sonet climb will not happen overnight. Products will be introduced at each logical point in the process, and service providers will learn them, use them and help refine them. Nor will networks transition overnight from a synchronous/asynchronous mix to synchronous only. These and other safety nets will be required along the way.
The objective of our Special Report was to have suppliers reflect on the development of their Sonet products and provide some insight into their product-development plans. Of course, product plans are a sensitive issue. But what comes across in these stories is the length to which suppliers have gone to understand the needs and wish lists of the service providers who will use their products. Also apparent are the many paths that are available to meet those needs and the tradeoffs that are faced along the way.
With a true sense of partnership, then, whether it was achieved willingly or unwillingly, manufacturers and service providers are preparing for the final 10% ascent. As they do so, they will be finalizing the foundation of telecommunications networks for years to come.
To the editor:
In "Fiber to the desk formulates the right prescription" (Lightwave, October 1994, page 48), there are some inaccuracies regarding our communications design work for Sterling Winthrop Pharmaceutical Co. The statement by Andy Poake at Reliable Telcom, the installing contractor, that implies the fiber-optic cable was spliced at the closets and main distribution frame is not accurate; array connectors and fanouts were used. No splices were allowed in the cable runs. All ST terminations were specified as epoxy or hot-melt adhesive; the article implies that ST quick-connects were permitted. Our design did not include quick-connects because of the potential for fiber pistoning and damage from rough handling or temperature changes.
Poake states he had difficulty with the cable tray and expressed that conduit should have been used instead. While Reliable was free to choose the installation method, other contractors have confirmed that using rollers in the tray, rather than lifting the cables into it, section by section from a ladder, would have eased the process. Reliable could also have proposed to use or supply innerduct to reduce installation time.
It`s true that initial installation in conduit is easier for the contractor. However, cable tray was chosen for this project because it offers advantages to the owner that conduit does not.
Cable tray provides flexibility for future changes.
A cable tray installation is more compact than a conduit installation carrying the same amount of cable.
Cable tray does not require pull boxes.
Both the installed cost and the life-cycle cost of the cable tray system are less.
AT&T 3ALX ribbon fiber, which is routinely used by the regional Bell operating companies, was specified for several reasons.
Our design criteria, as established with the owner, were to provide a communications system that would be reliable, flexible and economical throughout its design life. Ease of installation is certainly an important consideration, but the above criteria took precedence.
William J. Burdick and
Steven C. Goldfarb, RCDD
The Kling-Lindquist Partnership Inc.