How Switches Build MAC Tables
Question
As frames are processed by a switch, which statement is true about how the switch builds its MAC table?
Answers
Explanations
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A. B. C. D.A
The initial function a bridge performs when it receives a frame is to update the bridge table with the source MAC address and the port it came in on if the MAC address was not previously known.
When a switch receives a frame, it examines the source MAC address in the frame's header to identify the sender's device. The switch then looks up the source MAC address in its MAC table to determine which port the sender is connected to. If the switch does not find an entry for the source MAC address in its MAC table, it adds one by associating the source MAC address with the port where the frame arrived (i.e., the inbound interface).
The switch then examines the destination MAC address in the frame's header to determine where to send the frame. If the switch finds an entry for the destination MAC address in its MAC table, it forwards the frame out the port associated with that MAC address (i.e., the outbound interface). If the switch does not find an entry for the destination MAC address in its MAC table, it floods the frame out all ports except the one it arrived on.
Therefore, the correct answer to the question is A. The source addresses of the frames are associated with the inbound interface.
