A switch is a networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device. It is a multiport network bridge that uses MAC addresses to forward data at the data link layer (layer 2) of the OSI model. Some switches can also forward data at the network layer (layer 3) by additionally incorporating routing functionality. Such switches are commonly known as layer-3 switches or multilayer switches.
Switches are different from routers, which forward data between networks. They can be hardware devices that manage physical networks or software-based virtual devices. Switches operate on the data-link layer, or Layer 2, of the Open Systems Interconnection (OSI) model. In a local area network (LAN) using Ethernet, a network switch determines where to send each incoming message frame by looking at the media access control (MAC) address. Switches maintain tables that match each MAC address to the port receiving the MAC address.
There are several types of switches in networking, including virtual switches, unmanaged switches, managed switches, and routing switches. Virtual switches are software-only switches instantiated inside VM hosting environments. Unmanaged switches are designed so that you can simply plug them in and they work, no configuration required. Managed switches, on the other hand, allow for more control over the network and can be configured to meet specific needs. Routing switches connect LANs and perform routing functions at OSI Layer 3 (network layer), directing traffic based on IP addresses.
In summary, a switch is a networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device. It operates on the data-link layer, or Layer 2, of the OSI model and determines where to send each incoming message frame by looking at the MAC address. There are several types of switches in networking, including virtual switches, unmanaged switches, managed switches, and routing switches.
