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Tomorrow's options for speeding up local area networks.

Users looking to move to faster local area networks (LANs) will soon have a number of options besides FDDI and the highly publicized asynchronous transfer mode, or ATM.

Ethernet, the father of LANs, is about to have a speedier offspring, operating at 100 Mb/s,or 10 times the speed of the "old man". To the dismay of standards enthusiasts, the Ethernet offspring will actually be twins--and dissimilar ones at that.

Last July, the IEEE 802.3 Higher Speed Study Group, the body charged with developing the Fast Ethernet standard, failed to agree on a single aproach. Instead, it voted to proceed with two rival draft standards, assigning them to different commitees for further development.

One Fast Ethernet faction wants to keep the same access method used in 10-Mb/s Ethernet, CSMA/CD (Carrier-Sense Multiple Access/Collision Detection). The second and smaller group prefers a new approach based on Hewlett- Packard's Demand Priority Access Method (DPAM). AT&T and Proteon have joined HP in supporting this alternate design, know as 100Base-VG

Ethernet powerhouses 3Com and SynOptics Communications, and startup Grand Junction Networks of Union City , Calif., were among the first to announce product for the 100-Mb/s CSMA/CD Ethernet, dubbed 100Base-X. They teamed with Intel, Sun Microsystems, Standard Microsystems, Corp. (SMC), National Semiconductor and LAN Media to form the Fast Ethernet Alliance.

Grand Junction Networks says it will ship a $399 Fast Ethernet adapter and a combined $7.250 ethernet and Fast Ethernet hub by year's end. The combined technologies are designed to allow uder to integrate the hub into existing networks and migrate to Fast Ethernet as applications demand.

Howard Chaney, the firm's chairman and CEO, expect Fast Ethernet to be used initally to connect high-speed servers. He feels it will replace only 6% to 8% of current 10Base-T networks by 1996.

3Com will rool out a complete suite of products for Fast Ethernet by mid-1994, including network adapters, hubs and 100-Mb/s interfaces to its NetBuiler II line of bridge/routers. Prices will be about two-and-a-half times those of its conventional 10-Mbs/s products. The new adapters will offer software-selectable operation at 10 or 100 Mb/s, and will support the Category 3 unshielded twisted-pair wiring that is central to the efforts of the Fast Ethernet Alliance.

SynOptics' strategy for high-speed networking includes support for both Fast Ethernet and ATM, based on switching hubs and dedicated ATM Switches. SynOptics says it will deliver new modules for its System 3000 hub in 1994 incorporating FastFrame and CelliFrame technology.

FastFrame supports mixed 10Mb/s and 100 Mb/s Ethernet connections, while CelliFrame allows the switch to translate between Ethernet packets at either speed and 53-byte ATM cells. This will enable Ethernet devices to communicate directly with ATM-Linked units. In a related move, SynOptices has also introduced a 15-port Lattis Cell ATM switch supporting dedicated 155-Mb/s links

Another member of the Fast Ethernet Alliance, SMC OF Hauppauge, N.Y., has embraced both camps by also offering products for the 100Base-VG design. However, while its CSMA/CD products iclude hub modules, fixed-port work group hubs and workstation adapter cards, its 100Base-VG offering is limited to a module for its switching hub.

Since 100Base-VG is based on a new design, it's perhaps understandable that few companies are rushing to introduce pre-standard products However, Accton Technologh Corp. of Fremont, Calif., used the recent Interop show to preview a line of Centium adapters for 100Base-VG that will operate at both 10 and 100 Mb/s. The products are scheduled for release in January.

Meanwhile, HP appears to have upstaged th Fast Ethernet Alliance by joining forces with IBM to propose a standard for 100-Mb/s. token ring networks based on its DPAM approch. The proposed 100VG-AnyLAN standard would replace 100Base-VG and cover both Ethernet and token ring products, allowing users to implement both types of Ethernet and token ring products allowing users to implement both types of networks at 100Mb/s. These nets would conect with their standard-speed counterparts through a speed-matching bridge running as software in a 100VG-AnyLAN hub.

HP AND IBM are positioning 100VG-AnyLAN as a desktop solution for high-performance workgroups and complementary feeder solution for transporting LAN data to ATM networks.

A draft standard is expected to be complete in the first half of 1994 with HP and IBM products availble in the same timeframe.

Let the battle begin.
COPYRIGHT 1993 Nelson Publishing
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1993 Gale, Cengage Learning. All rights reserved.

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Title Annotation:fast Ethernet technology
Author:Edwards, Morris
Publication:Communications News
Article Type:Column
Date:Dec 1, 1993
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Next Article:Hughes to link remote workers via ATM.

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