Ethernet is a shared resource in which end stations
(computers, servers, and so on) all have access to the
transmission medium at the same time. The result is
that only one device can send information at a time.
Given this limitation, two viable solutions exist:
• Use a sharing mechanism: If all end stations are
forced to share a common wire, rules must exist
to ensure that each end station waits its turn
before transmitting. In the event of simultaneous
transmissions, rules must exist for retransmitting.
• Divide the shared segments, and insulate them:
Another solution to the limitations of shared
resources is to use devices that reduce the number
of end stations sharing a resource at any given time.