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Physical Layer

Moves bits from one end to other.
No guarantee for service possible! (why?)
$\begin{figure}\centerline {\epsfig{figure=/home/sivasiva/cep/figs/eps/phy.eps,width=3in}}\end{figure}$

Media Dependent
Guided (Wire-ful!)

Copper (Co-axial, Twisted Pair)

Typically upto 100 Megabits/second

Fibre (Single mode, Multi mode)

Can transmit in Gigabits/second!

Unguided Media (Wireless Radio Spectrum)

Satellite

Typically channels of 64 kbps, 128 kbps

Microwave Links

1999-03-14