switch

A switch is a multiport bridge. It provides the same functionality, but with a higher port density. In addition, switches provide features that cannot be found in bridges.

• Switches are associated with the Data Link layer of the OSI Model.


• Switches build a forwarding database in a manner similar to bridges. Switches examine the source and destination Data Link address in each packet to build the database and make forwarding decisions.


• Switches connect multiple segments or devices and forward packets to only one specific port.


• You can connect a single device to a switch port or multiple devices to a switch port by using a hub.

Switches offer the following advantages over a non-switched network.

• Switches create separate collision domains.


• Switches provide guaranteed bandwidth between devices, if dedicated ports are used.


• Switches can be used to provide collision-free networking, if only one device is connected to each switch port.


• Switches enable full-duplex communication.


• Switches induce less latency than other segmentation solutions.


• Switches can simultaneously switch multiple messages.


• Switches can mix 10 Mbps- and 100 Mbps-capable devices, if the switch is a 100 Mbps switch.


• Ethernet switches can be implemented without re-cabling.

Switches have replaced bridges in most network applications.