What is Filtering and Forwarding of a Gigabit Switch?
When one packet comes in from any port of the switch, it will check the destination address besides the source address learning. The switch will look up the address table for the destination address. If not found, this packet will be forwarded to all the other ports except the port where the packet comes in. If found, and the destination address is located at different port from this packet comes in, the packet will be forwarded to the port where this destination address is located according to the information of address table. But, if the destination address is located at the same port as this packet comes in, this packet will be filtered.