Consider the Ethernet switching domain as shown in the following figure. For simplicity, let's assume a single VLAN across the Ethernet segment and untagged frames:
There are two switches A and B with all ports in the same VLAN. The switches are connected to each other with the connections from port A9 to B1 and A13 to B5. Let's consider that the host X connected to port 1 of switch A and called A1 wants to send a frame to host Y. Switch A receives the frame from host X on port A1, and does a lookup of its MAC table to find the port associated with the destination address of the ...