"Switch" is a foreign word, derived from the English "Switch", the original meaning is "switch", the Chinese technology industry introduced this word, translated as "exchange." In English, the verb "exchange" and the noun "switch" are the same word (note that "exchange" here refers specifically to the exchange of signals in telecommunications technology, and is not the same concept as item exchange).
In 1993, local area network switching equipment appeared. In 1994, there was a boom in switching network technology in China. In fact, switching technology is a switching product with simplified, low-cost, high-performance and high-port-intensive features, which embodies the complex operation of bridging technology in the second layer of the OSI reference model. Like the bridge, the switch forwards the information relatively simply by the MAC address in each packet. This forwarding decision generally does not consider the deeper other information hidden in the package. Unlike the bridge, the switch has a small forwarding delay and operates close to a single LAN performance, far exceeding the forwarding performance between ordinary bridged internetworks.
Switching technology allows shared and dedicated LAN segments to adjust bandwidth to mitigate bottlenecks in information flow between LANs. There are now switching products for Ethernet, Fast Ethernet, FDDI and ATM technologies.
Like traditional bridges, switches offer many networking features. The switch can economically divide the network into small conflicting domains, providing higher bandwidth for each workstation. The transparency of the protocol allows the switch to be installed directly in a multi-protocol network with simple software configuration; the switch uses existing network cards for cables, repeaters, hubs, and workstations, eliminating the need for high-level hardware upgrades; the switch is transparent to the workstation In this way, the management overhead is low, and the operations of adding, moving, and changing network nodes are simplified.
The use of specially designed integrated circuits allows the switch to forward information in parallel at all line rates at line rates, providing much higher operational performance than traditional bridges. For example, a single Ethernet port pair can provide a transmission rate of 14880 bps for a packet containing 64 octal numbers. This means that a "line rate" Ethernet switch with 12 ports supporting 6 parallel streams must provide an overall throughput of 89280 bps (6 streams of information X14880 bps/channel traffic). ASIC technology enables the switch to achieve this performance with more ports, and its port cost is lower than traditional bridges.