Ethernet is the most widely used local area network protocoL
The IEEE 802.3 Standard defines I-persistent CSMA/CD as the access method for
first-generation 10-Mbps Ethernet.
The data link layer of Ethernet consists of the LLC sublayer and the MAC sublayer.
The MAC sublayer is responsible for the operation of the CSMAlCD access method and framing.
Each station on an Ethernet network has a unique 48-bit address imprinted on its network interface card (NIC).
The minimum frame length for lO-Mbps Ethernet is 64 bytes; the maximum is 1518 bytes.
The common implementations of lO-Mbps Ethernet are lOBase5 (thick Ethernet), 10Base2 (thin Ethernet), lOBase-T (twisted-pair Ethernet), and lOBase-F (fiber Ethernet).
The 10Base5 implementation of Ethernet uses thick coaxial cable. lOBase2 uses thin coaxial cable. lOBase-T uses four twisted-pair cables that connect each station to a common hub. lOBase-F uses fiber-optic cable.
A bridge can increase the bandwidth and separate the collision domains on an Ethernet LAN.
A switch allows each station on an Ethernet LAN to have the entire capacity of the network to itself.
Full-duplex mode doubles the capacity of each domain and removes the need for the CSMAlCD method.
Fast Ethernet has a data rate of 100 Mbps.
In Fast Ethernet, autonegotiation allows two devices to negotiate the mode or data rate of operation.
The common Fast Ethernet implementations are 1OOBase-TX (two pairs of twistedpair cable), lOOBase-FX (two fiber-optic cables), and 100Base-T4 (four pairs of voice-grade, or higher, twisted-pair cable).
Gigabit Ethernet has a data rate of 1000 Mbps.
Gigabit Ethernet access methods include half-duplex mode using traditional CSMAI CD (not common) and full-duplex mode (most popular method).
The common Gigabit Ethernet implementations are 1000Base-SX (two optical fibers and a short-wave laser source), 1000Base-LX (two optical fibers and a long-wave laser source), and 1000Base-T (four twisted pairs).
The latest Ethernet standard is Ten-Gigabit Ethernet that operates at 10 Gbps. The three common implementations are lOGBase-S, 10GBase-L, and 10GBase-E. These implementations use fiber-optic cables in full-duplex mode.