10 Base-2:
10Base2, also called Cheapernet or ThinNet, is a 10-Mbps baseband Ethernet specification using a 50-ohm thin coaxial cable. 10Base2, defined in the IEEE 802.3a specification, has a distance limit of 185 meters per segment. 10Base2 is based on Manchester signal encoding transmitted over a thin coaxial cable. Minimum 0.5 meters (20 inches) between computer connections. Maximum 30 computers per segment. Follows “5-4-3 rule”, maximum overall length is 925 meters.
Uses thin coax that is cheaper and easier to install than thick Ethernet coax. Transceiver electronics built into NIC; NIC connects directly to network medium. Coax cable uses BNC connector.
Coax runs directly to back of each connected computer. T connector attaches directly to NIC
Useful when many computers are located close to each other. May be unreliable - any disconnection disrupts entire network.
10 Base-5:
10Base5, also called ThickNet, is a 10-Mbps baseband Ethernet specification using standard (thick) 50-ohm baseband coaxial cable. 10Base5, which is part of the IEEE 802.3 baseband physical layer specification, has a distance limit of 500 meters per segment. 10Base5 is based on Manchester signal encoding transmitted. 500 meter maximum segment length (1,640 feet). Uses transceivers attached to segment by means of a vampire tap. Minimum 2.5 meters (8 feet) between transceivers. Maximum 100 computers per segment. Follows the “5-4-3 rule” 5 segments, 4 repeaters, 3 populated segments. Maximum overall length is 2500 meters. Maximum distance from segment to computer is 50 meters (drop cable).
Thick Ethernet also requires termination to avoid signal reflectance. In some circumstances, transceivers may be inconvenient; e.g., workstations in a lab. Connection multiplexor connects multiple computers to a single transceiver:
o Each computer's AUI cable connects to connection multiplexor
o One AUI from multiplexor to Ethernet coax
Connection multiplexor completely invisible to attached computers
10 Base-t:
10BaseT, also known as 10Base-T, is a transmission medium specified by IEEE 802.3i that carries information at rates up to 10Mbps in baseband form using unshielded twisted pair (UTP) conductors with low cost Level 3 or better UTP wiring up to 100 meters (328 ft.). 10BaseT uses RJ45 connectors and sometimes 50-pin AMP connectors to a patch panel. Variously called 10Base-T, twisted pair or TP Ethernet. Replaces AUI cable with twisted pair cable. Replaces thick coax with hub
Extension of connection multiplexing concept. Sometimes called ``Ethernet-in-a-box''. Effectively a very short Ethernet with very long AUI cables can be connected into larger Ethernets
Protocol software and Ethernet wiring:
· All wiring technologies use identical Ethernet specification
o Same frame format
o Same CSMA/CD algorithms
· Can mix different technologies in one Ethernet
· NICs can provide all three connection technologies
Protocol software can't differentiate among wiring technologies
Comparison of wiring schemes:
· Separate transceiver allows computer to be powered off or disconnected from network without disrupting other communication
· Transceiver may be located in an inconvenient place
· Finding malfunctioning transceiver can be hard
· Thin coax takes minimum of cable
· Disconnecting one computer (or one loose connection) can disrupt entire network
· Hub wiring centralizes electronics and connections, making management easier
· Bottom line - 10Base-T most popular because of cost
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