The PC emerged as the most common desktop computer in the 1980s. LANs
emerged as a way to network PCs in a common location. Networking technologies
such as Token Ring and Ethernet allowed users to share resources
such as printers and exchange files with each other. As originally defined,
Ethernet and Token Ring provided network access to multiple devices on the
same network segment or ring. These LAN technologies have inherent limitations
as to how many devices can connect to a single segment, as well as the
physical distance between computers. Desktop computers got faster, the number
of computers grew, operating systems began multitasking (allowing multiple
tasks to operate at the same time), and applications became more networkcentric.
All these advancements resulted in congestion on LANs.
To address these issues, two device types emerged: repeaters and bridges.
Repeaters are simple Open Systems Interconnection (OSI) Layer 1 devices that
allow networks to extend beyond their defined physical distances (which were
limited to about 150 feet without the use of a repeater).
Bridges are OSI Layer 2 devices that physically split a segment into two and
reduce the amount of traffic on either side of the bridge. This setup allows
more devices to connect to the LAN and reduces congestion. LAN switches
emerged as a natural extension of bridging, revolutionizing the concept of
local-area networking.