Ethernet Cable

The Ethernet physical layer evolved over a considerable time span and encompasses quite a few physical media interfaces and several magnitudes of speed. The speed ranges from 1 Mbit s to 100 Gbit s in speed while the physical medium can range from bulky coaxial cable to twisted pair to optical fiber. In general, network protocol stack software will work similarly on all of the following types.

10 gigabit Ethernet is becoming more popular in both enterprise and carrier networks, with 40 Gbit s 1 2 and 100 Gbit s Ethernet 3 now ratified 4 . Higher speeds are under development. 5 Metcalfe now believes commercial applications using terabit Ethernet may occur by 2015 though he says existing Ethernet standards may have to be overthrown to reach terabit Ethernet.

The following sections provide a brief summary of all the official Ethernet media types section numbers from the IEEE 802.3-2008 standard are parenthesized . 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 adapters and switch ports support multiple speeds, using autonegotiation 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. A 10 100 1000 Ethernet port supports 10BASE-T, 100BASE-TX, and 1000BASE-T.