Citações de Wikipedia :
1000BASE-T (also known as IEEE 802.3ab) is a standard for gigabit Ethernet over copper wiring.
Each 1000BASE-T network segment can be a maximum length of 100 meters (328 feet), and must use Category 5 cable or better (including Cat 5e and Cat 6).
Portanto, são 100 metros (328 pés).