(i) With a regular hub, packets being sent simultaneously collide, causing retransmissions and thus delays. A switch, on the other hand, looks at the destination address, and sends the packet to that address on a separate wire, so no collision. Hence, it is called intelligent hub.
(ii) Repeaters are used in transmission systems to regenerate analog or digital signals distorted by transmission loss. Repeaters are generally used when transmission is to be done on long path.
