Ethernet

Ethernet

The IEEE 802.3 standard defines ethernet at the physical and data link layers of the OSI network model. Most ethernet systems use the following:

Carrier-sense multiple-access with collision detection (CSMA/CD) for controlling access to the network media.

Use baseband broadcasts

A method for packing data into data packets called frames

Transmit at 10Mbps, 100Mbps, and 1Gbps.

Types of Ethernet

10Base5 - Uses Thicknet coaxial cable which requires a transceiver with a vampire tap to connect each computer. There is a drop cable from the transceiver to the Attachment Unit Interface (AIU). The AIU may be a DIX port on the network card. There is a transceiver for each network card on the network. This type of ethernet is subject to the 5-4-3 rule meaning there can be 5 network segments with 4 repeaters, and three of the segments can be connected to computers. It uses bus topology. Maximum segment length is 500 Meters with the maximum overall length at 2500 meters. Minimum length between nodes is 2.5 meters. Maximum nodes per segment is 100.

10Base2 - Uses Thinnet coaxial cable. Uses a BNC connector and bus topology requiring a terminator at each end of the cable. The cable used is RG-58A/U or RG-58C/U with an impedance of 50 ohms. RG-58U is not acceptable. Uses the 5-4-3 rule meaning there can be 5 network segments with 4 repeaters, and three of the segments can be connected to computers. The maximum length of one segment is 185 meters. Barrel connectors can be used to link smaller pieces of cable on each segment, but each barrel connector reduces signal quality. Minimum