Ethernet or Token Ring?
Since IBM introduced Token Ring to the industry, both Token Ring and Ethernet were recognized as candidates for corporate LAN infrastructures. The great debate among LAN specialists focused upon the question, “Which is better—Token Ring or Ethernet?” The answer to that question most often depended on the user application. Early Token Ring limitations offered connection speeds at only 4 Mbps, while Ethernet supported 10 Mbps. It was perceived, therefore, that Ethernet was better because it offered more bandwidth. Later, 16 Mbps Token Ring technology made Token Ring more attractive, but by no means ultimately superior. Some users felt that Ethernet’s lack of guaranteed access made it unsuitable for environments such as manufacturing.
If an equipment operator needed to control heavy equipment and send start/stop commands over a network, for example, the network administrator wanted to ensure that the command actually would make it to the device. Dangerous conditions could arise if the network lost a control command due to a collision. Because Ethernet offers no such promises in a collision environment, the manufacturing industry tended to select Token Ring. Token Ring promises a user the token at a predictable rate, thereby allowing access to the network to send critical commands. Ethernet could make no such claim; therefore, it was frequently dismissed as a viable networking alternative on the manufacturing floor.
Another factor that caused users to select Token Ring was their mainframe computer type. If the user had IBM equipment, they tended to use Token Ring because much of the IBM equipment had Token Ring LAN interfaces. Therefore, IBM shops were practically forced to use Token Ring to easily attach equipment to their networks.
In an office environment where no guarantees of predictability were necessary, Ethernet found popularity. Ethernet cabling schemes were simpler than Token Ring, and minicomputer manufacturers included Ethernet interfaces in their workstations. As users became more comfortable with Ethernet, network administrators selected it more frequently.
With the introduction of LAN switching technologies, Ethernet now finds application in the manufacturing environment where it previously could not. Switching reduces the size of a collision domain and provides a higher throughput potential that makes it possible to use in manufacturing. Switched Ethernet with ports dedicated to single devices performs equally as well or better than switched Token Ring networks in a similar configuration.