Big-bang deployment not essential

In the best of situations, an upgrade to Gigabit Ethernet may only be a matter of swapping out a few Network Interface Cards and other network gear. But getting your whole infrastructure ready to utilize the new speeds may be more complicated, especially if you are dealing with legacy systems, as is the case at many agencies.

For example, the newest desktop computers have processors that run at multigigahertz speeds, but there are plenty of computers still around that run at 800 MHz or less. Users with older processors, plus the much slower internal buses that generally support them, will not get the same benefit from a boost in network speed as users who have newer desktop computers.

Cabling is another deployment issue. The 100 megabits/sec Fast Ethernet and Gigabit Ethernet run over the same Category 5 cable, but they use it differently.

Fast Ethernet uses two of the four twisted pairs of wire in the cable — one to transmit information and one to receive. Gigabit Ethernet uses all four pairs to transmit and receive.

That means only about half of the nodes or network endpoints that are fed by the Fast Ethernet network can be serviced with Gigabit Ethernet. So unless you've already provided for substantial redundancy in the network, you may have to take on the expense of additional cabling.

Those and other tweaks to your infrastructure could determine the speed of the upgrades. Unless you are given sufficient funds to upgrade everything at once, agency officials saddled with extensive legacy environments may be better off going with a phased upgrade to Gigabit Ethernet. The usual starting places with this approach are the backbone connections among servers, which can benefit significantly from greater bandwidth.

— Brian Robinson