A switch is a piece of computer networking equipment that connects network fragments. Switches look much like network hubs, however a switch usually possesses more brains than a network hub. Switches are able to examine data packets as they are transmitted, establishing the source and destination device of that packet, and transmitting it correctly. By transmitting each message to the module it was projected for, a network switch saves network bandwidth and puts forward higher performance than a hub.
Just like hubs, Ethernet implementations of network switches are the most familiar. Most Ethernet switches support either 10 Mbps, 100 Mbps, or 10/100 Mbps Ethernet standards. The switch is an integral part in Ethernet local area networks (LANs). Mid-to-large sized LANs have a number of linked managed switches. Small Office, Home Office (SOHO) applications generally use a single switch, or an all-purpose joined device such as gateway access to small office/home office broadband modules such as DSL router or cable, WiFi router.
Switches can perform at one or more OSI layer, such as physical, data link or transport. A device that performs concurrently at more than one layer is referred to as a multi-layer switch.
Typical Switch management features
(In order of basic to advanced):
Turn some particular port range on or off
Link speed and duplex settings
Priority settings for ports
MAC filtering - and other types of “port security” features which prevent MAC flooding
Use of Spanning Tree Protocol
SNMP monitoring of device and link health
Port mirroring (also named: Port monitoring, spanning port, SPAN port, Roving Analysis Port, link mode port)
Link aggregation (also called: bonding/trunking)
802.1X Network access control