Simple definition
A network switch connects devices on a local network and forwards Ethernet frames to the appropriate port.
Technical definition
An Ethernet switch learns source MAC addresses and builds a forwarding table that associates those addresses with its ports. Managed switches may also provide VLANs, Spanning Tree Protocol (STP), link aggregation and Power over Ethernet (PoE).
What is a switch used for?
Connect computers, servers, wireless access points, IP phones and network cameras within a local network.
Practical example
A PoE switch can carry network traffic and supply electrical power to a compatible wireless access point over one Ethernet cable.
Common issues
- Ring causing a diffusion storm
- Port placed in the wrong VLAN
- Food PoE insufficient
- Link negotiated at too low speed
Related terms
Key takeaway: This entry explains the general operation of the term. Exact settings may vary depending on software, vendors and environments.