Sonet interoperability needs FiberopticNet

May 1st, 1996

Sonet interoperability needs FiberopticNet

George Kotelly

Executive Editor

An ongoing, industry-wide optical test network, called FiberopticNet for the purposes of discussion, is recommended to fully demonstrate the compliance of vendor transmission equipment to deliver Synchronous Optical Network (Sonet) interoperability.

The need for such a test network was accentuated by observances made at the Networld+Interop 96 networking technology trade show held last month in Las Vegas, which highlighted its InteropNet network (see page 1). This local area network interconnected nearly all of the several-hundred exhibitor booths; provided them with voice, video and data communications as desired; and displayed its networking capabilities to attendees in a live, highly visible atmosphere.

Its real purpose, though, is to function as a continuous learning experiment in designing, constructing, installing, troubleshooting and maintaining a complicated, multiprotocol, multivendor network. Used at several trade shows, the portable network can be set up in three days even though it contains more than 200 miles of fiber-optic cable and twisted-pair copper wire and more than 4000 pieces of networking equipment valued at $15 million.

But here is the key advantage of the network`s success: All the network equipment and all the engineering personnel and support are contributed--that means free--by some 110 companies. In turn, the contributing companies, including competitors, benefit from working in a multiequipment, multitechnology infrastructure, thereby gaining innumerable interoperability and performance experience.

The InteropNet also helps to shorten the learning curve of new technologies, prove the interoperability of new technologies, and educate vendors and attendees. It strives to reflect all the network communications demands inherent in current organizations: connecting equipment from diverse vendors, linking multiple local and remote sites, and using different cabling and protocols.

Moreover, the InteropNet changes in size, scope and direction in concert with the evolvement of new industry and networking challenges, technologies and standards. It currently runs three different protocols--TCP/IP, IPX and AppleTalk--over several transport technologies, such as 10Base-T, Ethernet, ATM, LAN Emulation over ATM (LANE), 100Base-T, 100VG-AnyLAN and OC-12 (622-Mbit/sec) ATM.

New technologies are deployed in conjunction with established technologies, such as Ethernet, Token Ring and Fiber Distributed Data Interface--a key problem to network planners who are trying to preserve investment and infrastructure while providing a migration path to new and expanding services and deployments.

More important, InteropNet is a win situation for all participants. Attendees observe practical applications of a working replica of a company-scale interoperable network. Exhibitors gain the opportunity to demonstrate their equipment and techniques in a working network. Contributing companies of equipment and personnel gain attention, publicity and experience by showing how their wares can interoperate and perform efficiently and reliably. And the whole networking industry advances by pushing technological barriers, promoting open standards and confirming equipment interoperability.

In contrast to the vendor cooperation of InteropNet, Sonet network transmission equipment vendors have singularly performed interoperability testing in conformance with the Open Systems Interconnection (OSI) protocols specified by the Sonet Interoperability Forum and Bellcore. Last summer, at the National Fiber Optic Engineers Conference, Fujitsu Network Transmission Systems Inc., Ando Corp. and Bellcore combined hardware and software resources to demonstrate the transport of OSI seven-layer protocol stack capabilities over data communications channels and an Ethernet link (see Lightwave, August 1995, page 1).

Based on third-party testing, another transmission equipment vendor, Alcatel Network Systems, claimed interoperability between its equipment and that of the multiple vendors who participated in the NFOEC demonstration (see Lightwave, January 1996, page 1).

High-speed, Sonet fiber-optic networking technology is moving slowly into commercial applications because network designers and planners prefer to select equipment from several vendors based on price and performance. More important, though, they want assurances that different vendors` equipment will interoperate--that is, plug and play. To achieve that goal, more Sonet interoperability testing by several cooperating vendors is necessary.

Rather than single-supplier testing, a unified, industry-supported FiberopticNet is needed to prove and promote Sonet interoperability.

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