Switching of frames is based on the DMAC address contained within a frame. The switch builds a table that maps MAC addresses to switch ports. It uses this information to decide which ports the frames should be sent to. The table contains both static and dynamic entries. Network administrators can configure static entries to create a fixed mapping between DMAC address and switch ports.
The frames also automatically update the MAC table with an SMAC address, which is the dynamic MAC address of the equipment sending the frame. Dynamic entries are removed from the MAC table if no frame with the corresponding SMAC address appears within a specified time frame.