Sonet interoperability scores at NFOEC 96

Sonet interoperability scores at NFOEC `96

George Kotelly

Executive Editor

Multivendor cooperation in dealing with Synchronous Optical Network (Sonet) standards-based internetworking of transmission equipment played a dominant role at the twelfth annual 1996 National Fiber Optics Engineers Conference (nfoec), held recently in Denver. Two major Sonet interoperability presentations were exhibited that included several heretofore competitive vendors.

The demonstrations initiated a new era of teamwork to achieve the goal of true Sonet interoperability: the mixing and matching of Sonet equipment from different manufacturers for implementation in public and private fiber-optic networks. Market and user demands for high bandwidth on demand via the free selection of different network elements, plus open competition following passage of the Telecommunications Act of 1996, have finally convinced equipment makers to band together and meet Sonet specifications.

The need for optical equipment suppliers to deliver true Sonet interoperability has been well documented in our publication (see Lightwave, May 1996, page 4; January 1996, page 1; and August 1995, page 1). The promise of Sonet networking cannot be fulfilled without standards compliance and network interoperability. Without meeting these requirements, the whole concept of multivendor Sonet ring networks is unworkable.

But results have been slow in coming, mainly because individual vendors prefer to gain a market edge by incorporating confidential methods for adherence to the Open Systems Interconnection (OSI) protocol stack specified by Bellcore, the Sonet Interoperability Forum and the American National Standards Institute.

Fortunately, at nfoec `96, vendor cooperation in support of Sonet interoperability permeated the exhibit floor. In one presentation, Bellcore set up a fiber-optic network in its booth that confirmed the first public demonstration of Sonet operations communications interoperability across the full, seven-layer, OSI protocol stack using different vendors` hardware and software.

Bellcore contributed ocat and Danet ositest software test tools and suites that provided supplier-neutral Sonet/SDH protocol analysis and performed successful point-to-point operations communications between a Fujitsu FLM 600 Sonet add/drop multiplexer and a Lucent DDM-2000 OC-3 Sonet multiplexer. Protocol access and the platform for the Bellcore software was furnished by an Ando Corp. AE-5150S protocol analyzer and two Ando Corp. AP-9460B Sonet analyzers.

Being able to use the Sonet data communications channel (DCC) to transport operations communications information enables network providers to centralize total management control of Sonet networks. Presently, carriers work around the interoperability issue by deploying single-vendor equipment or complex, extended overlay networks to control and maintain their Sonet networks.

"Sonet standards that exist today support interoperability, but they do not guarantee it," said John Palladino, Bellcore Sonet interoperability project manager, "Different suppliers` equipment can pass conformance tests and still not interoperate."

In the second demonstration, Tellabs Operations Inc., Lucent Technologies, Northern Telecom (Nortel) and Fujitsu Network Communications showed how their equipment worked in concert, achieving "plug and play" operations. The fiber-networked equipment included the Tellabs Titan 5500 digital cross-connect system, the Fujitsu FLM 600 Sonet add/drop multiplexer, the Lucent DDM-2000 OC-3 Sonet multiplexer, and the Nortel s/dms TransportNode OC-3 Express network element, and their respective network management systems. In the Tellabs booth, live video was transmitted, controlled and provisioned between the Titan 5500 system and each of the other vendors` multiplexers at OC-3 and OC-12 rates. DCC routing functions allowed access to remote add/drop multiplexers and the operation, administration, monitoring and provisioning of Sonet network elements by delivering messages through the centralized Titan 5500 system.

Says Mike Unger, Nortel group vice president, Sonet transport, "It`s one thing for products to interconnect, but it`s quite another to have end-to-end network visibility and control that this solution provides." Adds Richard Taylor, vice president and general manager, Tellabs Digital Systems Division, "Carriers will reap the true benefits of Sonet networking when suppliers work together to achieve transparent networking."

These two Sonet interoperability demonstrations prove that network and service providers can now mix and match fiber-optic network products from multiple vendors and be confident that the products will work together reliably, efficiently and affordably. It`s a win situation for the entire communications industry--Sonet network equipment vendors, network and service pro viders, and end-users. q

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