 it is obvious that with the exception of the Peripheral Compo- nent Interconnect (PCI) bus, Industry Standard Architecture (ISA), Extended Industry Standard Architecture (EISA), and Microchannel Architecture (MCA) buses do not have the capability to transfer data at a rate anywhere near 1 Gbits/s. Even when a 32-bit PCI bus is used, its the- oretical throughput is 132 Mbytes X (8 bits/byte) or 1.056 Gbits/s. Howev- er, because a computer needs cycles to retrieve data from a disk and initi- ate an adapter transfer, most PCI-based PCs can achieve a sustained data transfer only under 500 Mbits/s. However, modifications to Windows NT and the use of Windows 2000 with high-performance 1 GHz Pen- tium III processors and 64-bit PCI adapters operating at 66 MHz have resulted in a sustained data transfer of 900 Mbps. When contemplating the installation of a Gigabit Ethernet switch-to- server connection, it is important to carefully consider both the data path and the clock rate of the PCI bus. Unfortunately, the 32-bit data path and 33-MHz clock rate is the most common bus found in workstations and servers. Fortunately, and for added cost, some servers can be obtained with either a 64-bit data path and 33 MHz of clock speed or a 64-bit data path and 66 MHz of clock speed. The latter type of system provides the capability to effectively support Gigabit Ethernet transmission. REDUNDANCY A second major limitation of Gigabit Ethernet is its lack of redundancy. Unlike FDDI, which provides built-in redundancy through a self-healing ring, Gigabit Ethernet does not, and a break between a Gigabit Ethernet switch and another switch or file server can Fiber in the LAN be very disruptive to a company. Recognizing this problem, some com- panies introduced dual-port network adapters with an automatic cutover capability. While such adapters are more expensive than single-port adapters, for organizations that require redundancy, the added cost may be well worth reaching deeper into one's pocket. This page intentionally left blank. CHAPTE