OSI model
<p>Nov 08, 2010 11:04 AM
 
OSI Model  Open Systems Interconnection model. devel in 1978.  7 layer protocol.
 
Each layer gets services from the layer below it and provides services to the layer above it.
(Bob note:  similarity to brain/ bio).
 
Networks today are based on TCP/IP stacks.
 
An N+1 layer requests services from the N entity.
protocol data units.
 
A SERVICE DATA UNIT is a specific unit of data that is passed down to a lower layer.
 
In effect, the SDU is the payload of a given PDU.
 
 
 
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