- Shared medium
In
telecommunication , a shared medium is a medium or channel ofinformation transfer that serves more than ones user at the same time.Most channels only function correctly when one user is transmitting, so a
channel access method is always in effect.In
circuit switching , each user typically gets a fixed share of the channel capacity. Amultiplexing scheme divides up the capacity of the medium. Common multiplexing schemes includetime-division multiplexing andfrequency-division multiplexing . Channel access methods for circuit switching includetime division multiple access ,frequency-division multiple access , etc.In
packet switching , the sharing is more dynamic -- each user takes up little or none of the capacity when idle, and can utilize the entire capacity if transmitting while all other users are idle. Channel access methods for packet switching includecarrier sense multiple access ,token passing , etc.
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