Bridges are self-learning (plug-and-play) devices that implement filtering/forwarding of frames on the same LAN. A bridge maintains a bridge table, which is a mapping between MAC addresses of nodes in the LAN and its (the bridges) interfaces.

When the bridge is first turned on, its bridge table is empty. Explain how a bridge learns the information that it uses to fill in its bridge table.

(b) Consider the following diagram of a LAN composed of three LAN segments connected by a bridge. Assume that the bridge table starts off empty and the given sequence of frames is sent, in the given order (frame 1, frame 2, etc.). As the bridge filters the frames it is using the standard bridge-learning algorithm to fill in its table. For each frame write down to which interfaces (if any) the Bridge forwards the frame (the answer to the first one is filled in for you).

Frame	Source Node	Destination Node	Bridge forwards frame to interfaces #
1	A	D	2, 3
2	H	D
3	C	H