Varieties of Ethernet

The following sections provide a brief summary of all the official ethernet media types. In addition to these official standards, many vendors have implemented proprietary media types for various reasons—often to support longer distances over fiber optic cabling.

Many Ethernet cards and switch ports support multiple speeds, using auto-negotiation to set the speed and duplex for the best values supported by both connected devices. If auto-negotiation fails, a multiple speed device will sense the speed used by its partner, but will assume half-duplex.

A 10/100 Ethernet port supports 10BASE-T and 100BASE-TX and a 10/100/1000 Ethernet port supports 10BASE-T, 100BASE-TX, and 1000BASE-T.

10 Mbps Ethernet ( 10Mbit/Second)

1. 10BASE5 (also called Thick wire or Yellow Cable) — this is the original 10 Mbit/s implementation of Ethernet. The early IEEE standard uses a single 50-ohm coaxial cable of a type designated RG-8, of maximum length 500 meters. Transceivers could be connected by a so-called “vampire tap”, which was attached by drilling into the cable to connect to the core and screen, or using N connectors at the end of a cable segment. An AUI cable then connected the transceiver to the Ethernet device. Largely obsolete, though due to its widespread deployment in the early days, some systems may still be in use. It requires precise termination at each end of the cable.
2. 10BASE2 (also called Thin wire or Cheaper net) — 50 ohm RG-58 coaxial cable, of maximum length 200 meters, connects machines together, each machine using a T-adaptor to connect to its NIC, which has a BNC connector. Requires termination at each end. For many years this was the dominant 10 Mbit/s Ethernet standard.
3. Star LAN 10 — First implementation of Ethernet on twisted pair wiring at 10 Mbit/s. Later evolved into 10BASE-T.
4. 10BASE-T — runs over 4 wires (two twisted pairs) on a cat-3 or cat-5 cable up to 100 meters in length. A hub or switch sits in the middle and has a port for each node.
5. FOIRL — Fiber-optic inter-repeater link. The original standard for ethernet over fibre.
6. 10BASE-F — A generic term for the family of 10 Mbit/s ethernet standards using fiber optic cable up to 2 kilometers in length: 10BASE-FL, 10BASE-FB and 10BASE-FP. Of these only 10BASE-FL is in widespread use.
7. 10BASE-FL — An updated version of the FOIRL standard.
8. 10BASE-FB — Initially intended for backbones connecting a number of hubs or switches, it is now obsolete.
9. 10BASE-FP — A passive star network that required no repeater, it was never implemented.

Fast Ethernet (100Mbit/Second)

Fast Ethernet is a collective term for a number of Ethernet standards that carry traffic at the nominal rate of 100 Mbit/s, against the original Ethernet speed of 10 Mbit/s.
Fast Ethernet is no longer the fastest form of Ethernet: Gigabit Ethernet and the new 10 Gigabit Ethernet standards are 10 and 100 times faster, respectively.

1. 100BASE-T — A term for any of the three standards for 100 Mbit/s ethernet over twisted pair cable up to 100 meters long. Includes 100BASE-TX, 100BASE-T4 and 100BASE-T2. In practical scenarios, the cable can be extended up to 150 meters but it is not advisable.
2. 100BASE-TX — Similar star-shaped configuration to 10BASE-T. It also uses two pairs, but requires cat-5 cable to achieve 100Mbit/s.
3. 100BASE-T4 — 100 Mbit/s ethernet over cat-3 cabling (as used for 10BASE-T installations). Uses all four pairs in the cable. Now obsolete, as cat-5 cabling is the norm. Limited to half-duplex.
4. 100BASE-T2 — No products exist. 100 Mbit/s ethernet over cat-3 cabling. Supports full-duplex, and uses only two pairs. It is functionally equivalent to 100BASE-TX, but supports old cable.
5. 100BASE-FX — 100 Mbit/s ethernet over multimode fibre. Maximum length is 400 meters for half-duplex connections (to ensure collisions are detected) or 2 kilometers for full-duplex.

Gigabit Ethernet

Gigabit Ethernet (GbE) is a term describing various technologies for implementing Ethernet networking at a nominal speed of one gigabit per second.

Gigabit Ethernet is supported over both optical fiber and twisted pair cable. Physical layer standards include 1000BASE-T, 1 Gbit/s over cat-5e copper cabling and 1000BASE-SX for short to medium distances over fiber.

While it is currently deployed in high-capacity backbone network links (for instance, on a high-capacity campus network) its speed is largely not yet required for small network installations. Gigabit Ethernet has begun to penetrate the desktop (as of 2004), shipping standard on Apple’s Power Mac G5, the notebook (Apple’s Power Book), and is built into some high-end Pentium and Athlon motherboards. Desktop applications for it include professional video editing.

It is no longer the fastest Ethernet standard, with the ratification of 10 Gigabit Ethernet in 2002

1. 1000BASE-T — 1 Gbit/s over cat-5e or cat-6 copper cabling.
2. 1000BASE-SX — 1 Gbit/s over multi-mode fiber (up to 550 m).
3. 1000BASE-LX — 1 Gbit/s over multi-mode fiber (up to 550 m). Optimized for longer distances (up to 10 km) over single-mode fiber.
4. 1000BASE-LH — 1 Gbit/s over single-mode fiber (up to 100 km). A long-haul solution.
5. 1000BASE-CX — A short-haul solution (up to 25 m) for running 1 Gbit/s Ethernet over special copper cable. Predates 1000BASE-T, and now obsolete.

10 Gigabit Ethernet

Ten-gigabit Ethernet (XGbE or 10GbE) is the most recent (as of 2002) and fastest of the Ethernet standards.

IEEE 802.3ae defines a version of Ethernet with a nominal data rate of 10 Gbit/s, ten times faster than gigabit Ethernet.

The new 10 gigabit Ethernet standard encompasses seven different media types for LAN, MAN and WAN. It is currently specified by a supplementary standard, IEEE 802.3ae, and will be incorporated into a future revision of the IEEE 802.3 standard.

1. 10GBASE-CX4 — designed to support short distances over copper cabling, it uses InfiniBand 4x connectors and CX4 cabling and allows a cable length of up to 15 m.
2. 10GBASE-SR — designed to support short distances over deployed multi-mode fiber cabling, it has a range of between 26 m and 82 m depending on cable type. It also supports 300 m operation over a new 2000 MHz.km multi-mode fiber.
3. 10GBASE-LX4 — uses wavelength division multiplexing to support ranges of between 240 m and 300 m over deployed multi-mode cabling. Also supports 10 km over single-mode fiber.
4. 10GBASE-LR and 10GBASE-ER — these standards support 10 km and 40 km respectively over single-mode fiber.
5. 10GBASE-SW, 10GBASE-LW and 10GBASE-EW. These varieties use the WAN PHY, designed to inter operate with OC-192 / STM-64 SONET/SDH equipment. They correspond at the physical layer to 10GBASE-SR, 10GBASE-LR and 10GBASE-ER respectively, and hence use the same types of fiber and support the same distances. (There is no WAN PHY standard corresponding to 10GBASE-LX4.)
6. 10GBASE-T — Uses unshielded twisted-pair wiring.10GBASE-T should be ready by the Northern Hemisphere summer of 2006.