History of the Switch
"Switch" is an imported word, originated from the English "switch", the original intention is "switching", the Chinese technology industry in the introduction of this term, translated as "exchange." In English, the verb "exchange" and the noun "switch" are the same word (note that the "exchange" here refers to the exchange of signals in telecommunications technology, not the same concept as the exchange of goods).
1993, the local area network Exchange equipment appeared, in 1994, the domestic set off the Exchange network technology upsurge. In fact, switching technology is a simplified, low-cost, high-performance and high-end port-intensive exchange products, embodies the bridging technology complex switching technology in the OSI Reference model of the second level of operation. Like a bridge, a switch forwards the information relatively simply by the MAC address in each packet. This forwarding decision generally does not take into account the deeper information hidden in the package. Unlike bridges, switch forwarding latency is small, and operations are close to a single LAN performance, far exceeding the forwarding performance between common bridging Internet networks.
Switching technology allows the bandwidth adjustment of shared and dedicated LAN segments to mitigate bottlenecks in the flow of information between LANs. There are already switched products for Ethernet, Fast Ethernet, FDDI, and ATM technology.
Similar to the traditional bridge, the switch provides many network interconnection functions. The switch can economically divide the network into small conflict domains, providing higher bandwidth for each workstation. The transparency of the Protocol allows the switch to be installed directly in the Multi-Protocol network in the case of simple software configuration; switches use existing cables, repeaters, hubs, and workstation network adapters without the need for high-level hardware upgrades, and the switch is transparent to workstations, which is inexpensive to manage, simplifying network node growth, Mobile and network-changing operations.
The use of specially designed integrated circuits enables switches to forward information in parallel to all ports at line rates, providing much higher operational performance than conventional bridges. In theory, a single Ethernet port can provide a 14880bps transmission rate for packets containing 64 octal. This means that a "line rate" Ethernet switch with 12 ports that supports 6 parallel streams of data must provide a total throughput rate of 89280bps (6 streams of x14880bps/traffic). Special-Purpose Integrated circuit technology enables the converter to achieve the above performance in more ports, and its port cost is lower than the traditional bridge.