Switching

The term "switching" is used to refer to various mechanisms that take place on both switches and routers. In its most basic form, switching simply refers to the process by which a device decides out of which interface to send a frame or packet. Switching can take place on Layer 2 or Layer 3.

Another similar term that is often used is forwarding.

Layer 3 switching can also be referred to as Routing, but in some contexts the term switching is used. One must observe the context in which these terms are used to determine their meaning.

Layer 2 switching can take place using several mechanisms including:

• Cut-through switching
• Store and forward switching

Layer 3 switching can take place using several mechanisms including:

• Process switching
• Fast Switching
• Cisco Express Forwarding (CEF), also called topology based switching