Gigabit Ethernet

 

 

 

 

 

 

Media Access Control (MAC)

 

 

 

 

 

 

 

 

 

 

 

 

 

Gigabit Media Independent Interface (GMII)

 

 

 

 

 

 

1000Base-X

 

 

 

 

 

 

 

1000Base-T

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8B/10B encoder/decoder

 

 

 

 

 

 

encoder/decoder

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1000Base-LX

 

1000Base-SX

 

1000Base-CX

 

 

 

1000Base-T

 

 

 

 

 

 

 

 

Shielded

 

 

 

 

 

 

 

LWL

 

SWL

 

 

 

 

 

UTP

 

 

 

 

 

 

 

 

Balanced

 

 

 

 

 

 

 

Fiber Optic

 

Fiber Optic

 

 

 

 

 

Cat 5e

 

 

 

 

 

 

 

 

Copper

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IEEE 802.3z physical layer

 

 

IEEE 802.3ab

 

 

 

 

 

 

 

 

physical layer

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(C) Herbert Haas 2005/03/11

 

 

 

 

 

 

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Gigabit Ethernet has been defined in March 1996 by the working group IEEE 802.3z. The GMII represents a abstract interface between the common Ethernet layer 2 and different signaling layers below. Two important signaling techniques had been defines: The standard 802.3z defines 1000Base-X signaling which uses 8B10B block coding and the 802.3ab standard uses 1000Base-T signaling. The latter is only used over twisted pair cables (UTP Cat 5 or better), while 1000BaseX is only used over fiber, with one exception, the twinax cable (1000BaseCX), which is basically a shielded twisted pair cable.

BTW: The "X" stands for block coding.

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