Switching
This is the process of moving data within a network. A switch has devices connected on different ports. The switches main job is to keep a table of which MAC address is connecting through which port (this is a many to one relationship as there could be other switches in the network). This is a layer 2 process so just works on the level of MAC addresses. There are 3 operations involved in switching that will involve looking at the layer 2 header.
- Learn: when a new frame arrives on a port with a previously unknown MAC address as it source it updates its table,
- Flood: when a new frame arrives with a previously unknow MAC address as its destination it duplicates this frame and posts it on all other ports of the switch, and
- Forward: when a new frame arrives with a know MAC address as its destination it sends it along to the port associated to that address.