1000Base-T (Gigabit Ethernet, IEEE 802.3 Clause 40)
The 1000Base-T standard defines the transmission of Gigabit Ethernet (1 Gbit/s) via copper twisted pair cables. It is the successor to 100Base-TX and enables ten times higher speeds with similar cabling.
The most important features:
- Cabling:
1000Base-T uses four twisted wire pairs in network cables of category 5e or better (Cat5e, Cat6).
Unlike 10/100 Mbit/s, all four pairs are used simultaneously. Transmission takes place in both directions simultaneously (full duplex) on each pair. This is how the high data rate of 1 Gbit/s is achieved. - Transmission speed:
maximum 1 Gbit/s - Maximum cable length per connection:
100 m between end device and switch/hub - Topology:
Star-shaped - each end device has its own line to the central network device - Compatibility:
1000Base-T is downwards compatible with 10Base-T and 100Base-TX. Devices automatically negotiate the highest possible speed when establishing a connection ("auto-negotiation").
These properties make 1000Base-T suitable for modern networks with high data volumes, e.g. for servers, workstations, VoIP or multimedia applications. It is now the standard in most office and home networks.
Here is a clear comparison table for the three standards:
| Feature | 10Base-T | 100Base-TX | 1000Base-T |
|---|---|---|---|
| IEEE standard | IEEE 802.3 (Clause 14) | IEEE 802.3u | IEEE 802.3 (Clause 40) |
| Designation | Ethernet | Fast Ethernet | Gigabit Ethernet |
| Max. transmission rate | 10 Mbit/s | 100 Mbit/s | 1 Gbit/s |
| Cabling | Twisted pair, Cat3 or better | Twisted pair, Cat5 or better | Twisted pair, Cat5e or better |
| Used wire pairs | 2 pairs (1x transmit, 1x receive) | 2 pairs (1x transmit, 1x receive) | 4 pairs (transmit + receive simultaneously) |
| Max. Segment length | 100 m | 100 m | 100 m |
| Topology | Star (hub/switch as center) | Star (switch as center) | Star (switch as center) |
| Downwards compatible | - | to 10Base-T | to 10Base-T and 100Base-TX |
| Typical use | Small, simple networks | Faster office/industry networks | Today's standard in the office & home network |