From Fibre Channel for SANs


The FC-0 level is the physical link layer in the Fibre Channel architecture. Although its characteristics are well suited to optical fiber implementation, it is designed for maximum flexibility and allows use of several electrical technologies as well. Data transfer interfaces are defined for optical transmission over both single- and multi-mode fibers, with both lasers and LEDs, at both long (1300 1360 nm) and short (770 850 nm) wavelengths, and for electrical transmission over video coax, miniature coax, and shielded twisted pair cables. Transmission speeds are defined at 1.0625 Gbps, at half-, quarter-, and eighth-speed data rates, and recently at double- (2.125 Gbps) and quadruple-speed rates as well. This variety of possible technologies makes for a large range of customer and manufacturer choices regarding transmission medium, transmission distance, and price.

General Characteristics

The FC-0 level converts 10-bit transmission characters at a transmitting Port into serialized transmission signals that traverse a cable plant to a receiving Port. A cable plant consists of optical fibers or electrical cables with associated connectors and/or splices for optical fibers and grounding mechanisms for electrical cables. The FC-0 level at the receiving Port digitizes and deserializes the received signal into retimed 10-bit characters to be passed to the receiving Port s FC-1 level.

The transmission signal is binary, with a two-state transmission signal. A digital b 1 is encoded relative to b 0 as either more optical power (optical fiber) or a higher voltage on the center conductor (coaxial cable) or higher voltage on the conductor labeled + (twisted pair...

Products & Services
Wavelength Division Multiplexers (WDM)
Wavelength division multiplexers (WDM) are devices that combine light signals with different wavelengths, coming from different fibers, onto a single fiber. They include dense wavelength division multiplexers (DWDM), devices that use optical (analog) multiplexing techniques to increase the carrying capacity of fiber networks beyond levels that can be accomplished via time division multiplexing (TDM).
Fiber Optic Fault Locators
Fiber optic fault locators shine red laser light through jacketed fibers to identify breaks, bends, faulty connectors, splices and other causes of signal loss.
Serial Cables
Serial cables are used for the serial transmission of data. They support communication standards such as RS232, RS422, and RS485, as well as Fibre Channel, IEEE 1394 or FireWire® (Apple Computer, Inc.), and universal serial bus (USB).
Fiber Optic Attenuators
Fiber optic attenuators are devices that reduce signal power in fiber optic links by inducing a fixed or variable loss. They are used to control the power level of optical signals at the outputs of light sources and electrical-to-optical (E/O) converters. They are also used to test the linearity and dynamic range of photo sensors and photo detectors.
Optical Time Domain Reflectometers (OTDR)
Optical time domain reflectometers (OTDR) measure the elapsed time and intensity of light reflected along an optical fiber. They are useful tools for locating problems in an optical network as they can compute the distance to breaks or attenuation.

Topics of Interest

Introduction This chapter covers the design of the 8B/10B transmission code used for Fibre Channel transmission, and the transmitter and receiver states. 8B/10B Transmission Code Overview When data...

Absorption: The portion of optical attenuation in an optical fiber resulting from the conversion of optical power to heat; caused by impurities such as hydroxyl ions in the fiber. A/B Switch: A...

3.6   FIBER CHANNEL A channel is a well-defined, direct, and structured mechanism to transport information data between a source and a destination, and in some cases, to several destinations.

3.9   GIGABIT ETHERNET The Gigabit Ethernet (1000BASE-x), or GbE for short, is the natural evolution of two older standards, the 100 Mbit Ethernet (100BASE-x) and the 10 Mbit Ethernet (10BASE-T).

Exam Essentials List the main considerations when designing a basic fiber optic system. Remember that there are many ways to approach fiber optic system design and there are many different fiber optic...