How far can Gigabit Ethernet go?

One thing to consider when installing any LAN technology is how far it can reach over fiber-optic lines or copper wires.

Maximum distances for Gigabit Ethernet vary widely, depending on the medium. The technology is designed to carry data for 25 meters over coaxial cable, but this version isn't widely used. Gigabit Ethernet over Category 5 unshielded twisted pair wires (using 1000Base-T) can travel for 100 meters, but products supporting this don't exist yet. Because of the short distance, copper Gigabit Ethernet is likely to be limited to server connections.

Multimode fiber-optic lines (using 1000Base-SX) will get you as much as a kilometer, so they're good for in-building and campus wiring. Equipment vendors say they can send data 10 km across single-mode fiber (using 1000Base-LX), for a distributed campus. With proprietary extensions, Gigabit Ethernet can stretch as much as 70 km with Foundry Networks switches, and as much as 50 km on Packet Engines switches (using the designation 1000Base-LH).

Now that these distances are possible companies are starting to use Gigabit Ethernet for connecting campuses around a city in metropolitan-area networks.