Gigabit Ethernet (IEEE 802.3z / 802.3ab) delivers 1000 Mbps (1 Gbps) and comes in several physical-layer implementations, differing by medium:

Implementation	Medium	Max distance	Notes
1000BASE-T	Cat 5e/Cat 6 UTP copper (4 pairs)	100 m	Most common for desktop/office LAN cabling
1000BASE-SX	Multimode fiber (short wavelength, ~850 nm)	~550 m	Cost-effective fiber option for shorter runs
1000BASE-LX	Single-mode or multimode fiber (long wavelength, ~1300 nm)	Up to ~5 km (single-mode)	Used for longer backbone links
1000BASE-CX	Shielded copper (twinax), short-haul	~25 m	Used for very short connections, e.g. within a server rack

All variants present the same 1 Gbps MAC-layer interface upward, differing only in the Physical layer signaling and medium used — allowing network designers to pick the right implementation based on distance, cost, and existing cabling infrastructure.