1000base-t gigabit ethernet enables operation over the extensive installed base of legacy category 5 cabling systems and, by default, the category 5 cabling systems currently being installed.

    it provides optimal full-duplex 1000mb/s ethernet service over category 5e links as defined by ansi/tia/eia-568-a-5. topology rules for 1000base-t are the same as those used for 100base-t. category 5 and 5e link lengths are limited to 100 meters.