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Chapter 28
Applications and Business Issues of Fiber Channel

Ed Frymoyer

For data communications managers looking for a networking technology that offers scalable bandwidth, connectivity, distance and protocol multiplexing, and guaranteed delivery, fiber channel is an economical solution. Fiber channel is designed to improve information flow, not just transport data or bits. This chapter discusses the economics and technology fundamentals of fiber channel as a transport technology.

INTRODUCTION

Occasionally, new technologies transform ways of thinking — this is sometimes called a paradigm shift. Fiber channel is an example of such a technology.

Fiber channel is a high-speed information connection for all classes of computers across a wide range of system protocols, extensible in speeds up to gigabit rates and beyond. An industry initiative, which started in 1988, has produced a defined standard and an increasing number of practical installations in enterprises. This chapter examines fiber channel technology, benefits, and applications.

HOW FIBER CHANNEL DIFFERS FROM OTHER TRANSPORT TECHNOLOGIES

Fiber channel is an OSI technology that was developed independently, without any predefined structure and methodology. More than 60 companies helped define fiber channel — it is probably the most democratic standard ever designed.

Fiber channel offers:

  channel reliability and performance.
  use with multiple applications.
  the ability to share media.
  improved networking capabilities.

Fiber channel is designed to improve information flow, not just to transport data or bits. The emphasis is on interconnection of information by providing access, flexibility, application layer friendliness, data integrity, high availability, distance insensitivity, and seamless extension to higher rates as needed.

Shared Storage, Computing, and Network Resources

Although a sophisticated structure is necessary for such flexibility and performance, fiber channel enables a change of the computing paradigm. Fiber channel links both storage and computing resources. By linking local and distributed storage locations with the same access time (i.e., latency) as local-to-local locations, fiber channel creates a flattened memory space — the virtual local disk. Because performance is the same with local or distance storage or shared computer resources, fiber channel enables true mainframe downsizing using open systems client/server methodologies. The costs and user-friendliness of fiber channel can be compared with those of distributed personal computing methods. Fiber channel provides high-bandwidth multiple applications over a wide range of computer equipment, from the desktop to the glass house.

ATM and FDDI, among other transport technologies, are designed as frame or cell-based transports for physically carrying data over a networked structure. Applications must be adapted to the cell or frame transport methodology. As opposed to a physical connection construct such as FDDI or ATM, fiber channel is a systems-level technology. It also easily becomes a server technology; allowing high-performance sharing of storage, computing, and networking resources. Exhibit 1 compares the maximum data rates of various data communications technologies.

A primary advantage of fiber channel architecture is that it enables multiple server functions. One interconnect board (known as an N_Port or channel in the standard’s parlance) can inherently provide multifunctionality. Combined with a switched fiber channel network, this allows rapid access to distributed mass storage, distributed computing, and multiple networking resources. Fiber channel is thus unique as a transport technology whose structure provides all these functions. Because fiber channel is a clustering technology, it allows sharing of computing and storage resources over the same connections in a high-bandwidth, low-latency, time-multiplexed manner. Fiber channel implies multiple services, multiple applications, and fully scalable physical and logical service.


Exhibit 1.  Maximum Data Rate by Technology.

Fiber Channel Economics

The high-volume economics of SCSI and Ethernet determine the cost structure of fiber channel. Costs for these technologies, at speeds much lower than fiber channel, are well under $100 per connection. Gigabit fiber channel has matured rapidly — connectivity will soon be available for the same price of Ethernet in 1993. Currently, fiber channel connections — adapter boards with optical — are $1,000 to $2,500 (this is the original equipment manufacturer price). Soon prices with copper connections will be well under $500, and by the year 2000, will be under $100 for the simplest copper connection.

To be useful, a technology must have the appropriate high-volume economics and the business incentives necessary to achieve the volume. fiber channel economics can be compared with those of SCSI mass-storage serial upgrades based on 30M- and higher volume SCSI connections. The cost of these connections is, at most, $200 for a high-volume adapter board and much less for embedded connections such as those on disk drives. Long-term, fiber channel must provide much higher cost performance at the same cost as SCSI for both hosts and peripherals. The Ethernet network-connection market is comparable in volume with the SCSI market. The costs of Ethernet connections are far less than $100 per port in volume.


Exhibit 2.  Processor Speeds and I/O Standards Rates.

Fiber channel promises to approach these costs within the next few years, and seems to be ahead of the experience curve for gigabit connections. Gigabit at Ethernet prices seems achievable.


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