Why Do We Care? I am not an electrical engineer? Physical layer places constraints on what the hardware network infrastructure can deliver reality check Need to understand impact of the physical layer on the higher protocol layers 》 Fiber fiber copper? > Why do we need wires at all? > Error characteristic and failure modes 》 Effects of distance 55 Why Do We Care? I am not an electrical engineer? Physical layer places constraints on what the hardware network infrastructure can deliver = reality check Need to understand impact of the physical layer on the higher protocol layers »Fiber fiber copper? »Why do we need wires at all? »Error characteristic and failure modes »Effects of distance