Fibre Channel subset sparks diverse interest and applications

Oct. 1, 1995

Fibre Channel subset sparks diverse interest and applications


Fibre Channel-arbitrated loop (FC-AL) technology, a 100-megabit-per-second interconnect standard, is expected to debut in 1996, after seven years of study by an American National Standards Institute committee. It allows concurrent communication among workstations, supercomputers, mainframes, data storage devices and other peripherals.

Because Fibre Channel provides a total network bandwidth on the order of 1 terabit per second, it works 10 to 250 times faster than existing networks and can transmit at rates exceeding 1 gigabit per second in both directions simultaneously. It can also transport over existing protocols, such as Internet protocol, small computer systems interface (SCSI), high-performance parallel interface and intelligent peripheral interface, using fiber-optic cable.

This fiber-optic interconnect standard has received vendor support from Buslogic Inc., a SCSI host adapter hardware and software company in Santa Clara, CA. The company has included integration of FC-AL technology into its product development planning. According to Jesse Chen, president and chief executive, "Our channel plans emphasize strategic relationships with key system manufacturers to provide solutions for true `power` users who need to dramatically increase input/output.

"Our goal is to solidify development and marketing partnerships with leading technology companies to establish the foundation for a range of product offerings that are expected over the next year," Chen says.

In related Fibre Channel developments, Vitesse Semiconductor Corp., Camarillo, CA, has released two integrated circuits, the VSC7121 and the VSC7120, for FC-AL and FC-AL hub applications. According to Howey Chin, Vitesse director of standard product marketing, these two chips complete the company`s offerings of physical layer solutions for the Fibre Channel market. The two chips constitute 90% of the functionality of a low-cost Fibre Channel hub port.

The VSC7121 is a 1.0625-Gbit/sec quad port bypass circuit that contains four Fibre Channel port bypass circuits. It dissipates typically 0.5 watt. The VSC7120 is a Fibre Channel repeater and hub chip. The chip combines a clock recovery unit to retime serial data, a signal detection unit to detect the presence of valid Fibre Channel encoded serial data and a port bypass circuit to bypass faulty ports.

Additional insights about this new technology come from Stephen Montgomery, vice president and chief operating officer at Electronicast Corp., a market forecast consulting firm based in San Mateo, CA. "There are three different Fibre Channel topologies-- switched router or fabric, point-to-point, and Fibre Channel-arbitrated loop."

Montgomery explains that each connected Fibre Channel node has a port. Arbitrated- loop topology connects several tens of ports in a loop. Each port sees all messages and determines those that are meant to be accepted by that node.

"FC-AL is not competitive with Fibre Channel," Montgomery explains; it is, in effect, a subset of Fibre Channel. He projects a bullish market: "Next year, total consumption value (units that are purchased) for Fibre Channel adapters in North America is estimated at $22.9 million," he says. "In 1998, consumption value should soar to five times what it is for 1996--to $106.5 million. In the year 2000, total consumption value is forecast at $206.7 million."

Montgomery further explains that Fibre Channel is a serial link that generally acts as an interface to the parallel input/output of processors by means of a serializer/deserializer chipset. Fibre Channel is duplex and may be employed as a simple point-to-point link, a bidirectional loop or switched network. Its standards are relatively flexible concerning fiber type and emitter wavelength. The initial FC-AL fiber link is multimode, 266 megabytes per second, 650 nanometers and uses compact disk laser diodes test-selected from commercial production. As high-modulation-rate links are phased in, they should trend to other laser diodes at longer wavelengths and to singlemode fiber for longer lengths.

Additional forecasts are included in the report Fibre Channel 95: A Research Study. Ed Frymoyer, president of EMF Associates, Mountain View, CA, and Andy Prophet, president of AP Research, Cupertino, CA, also predict dramatic growth for Fibre Channel host adapter boards. The study projects the market to grow from $25 million in 1996 to $200 million in 1998. Over the long term, Fibre Channel is projected to be the most cost-effective, reliable method for transmitting high-volume input/output traffic, out-performing parallel SCSI and serial storage architecture in both performance and sales.

Yet another viewpoint comes from Phil Detwiler, vice president of worldwide marketing at Seagate Technology, Scotts Valley, CA: "Buslogic`s support of FC-AL is another example of the technology`s growing acceptance. With Buslogic`s role in the host adapter market, we look forward to introduction of FC-AL controller products as Seagate follows through with its plan for production of Fibre Channel drives in the coming months."

Fibre Channel direction

Arbitrated-loop technology provides a low-cost implementation of Fibre Channel that will afford the benefits of 100-Mbit/sec performance and connectivity over long distances. This implementation addresses the technology and usage trends of mass storage and shared computing in business environments, as well as the weaknesses of alternative strategies in meeting future requirements. The technology should continue to offer performance and interoperability enhancements through industry standardization and real-world implementation.

To ensure interoperability, Buslogic is establishing close working relationships with major Fibre Channel users, such as Hewlett-Packard Co. These relationships will help achieve connectivity between Fibre Channel devices, filling the gaps between standards and working results.

Ron Elred, Hewlett-Packard`s Fibre Channel program marketing manager, says Buslogic`s commitment to FC-AL should create an avalanche of cross-industry programs geared toward delivering Fibre Channel solutions. "Buslogic`s experience in the host adapter business will be instrumental to successful penetration into the personal computer server market."

Market expectations

Moving beyond standards debates, Buslogic is committed to providing Fibre Channel solutions that comply with the draft Fibre Channel standard, the Fibre Channel Systems Initiative, the SCSI profile and the private loop profile being developed by the Fibre Channel Association, while adding specific performance features that support real-world computing environments.

However, there are technologies that compete with Fibre Channel. Among these, says Jeff D. Montgomery, chairman of Electronicast, are massively parallel optical interconnect components. These devices (comprising opto-electronics, optical waveguide and any required connectors) operate over an array of four or more transmitters, receivers or both at one point, connected to an equivalent array by means of an optical waveguide, at another point. They are used within a single system or piece of equipment.

"This definition covers both synchronous and asynchronous links," Montgomery says. He notes that several companies have introduced massively parallel products. For example, Motorola has announced its Optobus 150-Mbit-per-channel, 10-channel duplex link. Vixel Corp. and Net Wave are offering prototype links. Hitachi, Fujitsu and Siemens are expected to announce array opto-electronics by the end of 1995.

Growth of massively parallel optical interconnect products has been projected from $12.75 million last year to $44.6 million in 1996. Dramatic growth will continue, averaging 125% per year to $508 million in 1999, Montgomery says. "This rapid growth will be driven by the continuing trend to higher-data-rate input/output per machine, the growing complexity of networks, the demand for higher processing throughput and the pressures for lower cost per channel and reduced size."

Original equipment manufacturers are expected to adopt Fibre Channel for high-performance mass storage subsystem interconnect and for high-availability, redundant subsystem interconnect. Using Fibre Channel for these "box-to-box" connections will break the SCSI-to-SCSI performance bottleneck, while retaining the flexibility of input/output channel connected storage subsystems. Added security may be derived from Fibre Channel`s long-distance connection.

Fibre Channel applications include clustering, shared computing, or parallel processing of business and scientific programs, video, high-resolution graphics, image manipulation or transaction processing. Software platforms typically associated with these applications include UNIX, Microsoft Windows NT and Netware. q

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