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Ethernet

It was  invented by Xerox in the 1970. the main idea came from the Alhanet in Hawaiin. it is a simple  LAN architecture with very little management overhead. It uses Carrier Sense Multiple Access/ Collision detection.

The main implementation run at 10 Mbps and at 100Mbps and the gigabit per second is completed.

The cabling method is either twister per, Fiber, thick or think cable
The cable and connection types are know as:

The bits are encoding the Manchester encoding and the standards received the name of  802.3

The way it works is as follow:

Before transmitting each station  checks the  channel, if the channel is idle it transmits while continuing to check the channel, but if the channel is in use the station waits until the current transmission ends. If a collision happens both stations back of time before rechecking the channel and starting again.

Frame size 

Minimum frame size  is 64 bytes.
Maximum frame size is 1518 bytes.
Data load is 46-1500 bytes.
There are 6 byte sender address and 6 bytes receiver address, and 6 bytes circle redundancy check.
Each Ethernet card contains an unique address assign by the card manufacturer.

Frame size format.

100 Mbps ETHERNET

Initial specification was to provide ten times the capacity at twice the cost. Main standard 100BaseT.

100BaseT 

Defined by 802.3 committee. Maintains CSMA/CD access method. Supporters include Intel, Digital, 3Com, and National Semiconductors. Maximum span 250 meters.

100BaseT physical layer

Three physical Layer standards. 100BaseTX for two pairs of Cat5 UTP. 100BaseT4 uses four pairs of Cat3 UTP. 100BaseF uses Fibre.

Gigabit Ethernet (1GE)

The physical layer is based on standards develop from a point to point technology called fibre channel. It is used to interconnect high speed switches. available for both LAN and WAN. Mainly full duplex on fiber. Implemented by Telcos in WAN
A 100 meter over Cat5 available. It is full duplex technology using 4 pairs of Cat5. This product is now available.
This has prove to be a high successful technology standards completed in July 1998. It competes with ATM in LAN backbones. Adapted by TELCOs like Telstra are now available, Next step is 10GE.

1GE Standards

10 Gigabit Ethernet

Due to be released in July 2002 Range of standards for LAN and WAN. Exclusively full duplez mo support for cllision detection. Fiber based. Very serious contender in WAN.

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Last modified: October 03, 2004