Recent Technology Protection Experience (Continued)
Storage Area Networks (Continued)
. . . only between a few sites. Fiber channel provides an inherently reliable method of transporting data. SCSI (which may ride on FC) presumes that data is delivered in order and reliably. To carry FC outside a data center, an extension system should maintain the same levels of performance and reliability regardless of the distances involved. Efforts focusing on solutions to FC long distance transport are documented by IETF draft standards focused on carrying FC over TCP/IP. Competing standards efforts such as iSCSI seek to extend the applicability of existing storage networking standards. As enterprise storage needs continue to grow, solutions are needed that can extend the reliable, high-performance characteristics of FC to SAN fabrics of thousands of kilometers, thereby unifying enterprise SAN islands into large geographically dispersed SAN systems . . .
High-Speed electro-optical networking
Generally, CDR systems suffer from extreme sensitivity to clock skew between clock domains within the CDR circuit. Managing this problem in the context of a typical GHz-rate deserializer requires extreme care to be used in matching of the clock paths and balancing of the clock distribution . . .
M-level pulse amplitude modulation (M-PAM) is a modulation technique that can be employed to reduce the symbol rate in data communication systems. . .
Optical transmission systems, such as those using Dense Wavelength Division Multiplexing (DWDM), provide extremely wide bandwidth for communications. There is a trade off between the lower cost of transport provided by wider bandwidth communications channels and their vulnerability to a large-scale disruption of communications . . .
In a WDM system that employs differential-phase-shift-keyed (DPSK) modulation, a DPSK demodulator is used for each channel. A DPSK demodulator typically takes the form of a delay interferometer (DI) followed by an optical-to-electrical (O-E) converter. The function of the DI is to convert phase-coded optical signals to intensity modulation before the signals are presented to the O-E converter. The function of the O-E is to convert ...