Packet Forwarding - packets forwarded to their destination based on paths described in routing tables. An IP checksum is calculated to assure that the packet has not been corrupted. Special Services - translations from one protocol to another, prioritization, packet filtering, authentication, etc. A Hub is a centralized switch box that allows multiple network connections but does not know where packets are supposed to go. Switches may also have protocol converters to convert the attached device's protocol to the form used by the switch core.
Switches filter incoming data packets by examining the packets link information.
Switches can also be configured to create Virtual LANs that enable a network administrator to set up connectivity groupings of specific users on a temporary basis. A LAN broken up into multiple segments can prevent unnecessary traffic by will reject a message originating on one network segment whose destination is not on the next network segment. Different manufacturers will support different combinations of LAN protocol translations. The traditional LAN switching used in Virtual LANs assume that the switch core is too fast to be saturated by any traffic being received. ATM or Frame Relay switching assumes that there is a capacity limit, and the system interacts with applications to meter data to assure that data can be transmitted without congestion.