A Cisco switch is mainly used to connect different devices such as computers, servers, printers, etc. in a local area network (LAN). It forwards packets from a port to a destination device by learning and filtering the destination address of the packets, thus realizing the communication between different devices in the network.
Cisco switches support a wide range of network protocols and services, and provide multi-level security features, including access control lists (ACLs), virtual LANs (VLANs), and port security, etc. Common series include the Cisco Catalyst series and the Cisco Nexus series, and each series comes with different models and configurations to meet the different requirements of users in terms of performance, number of ports, and features.