The sender side of rdt3.0 simply ignores (that is, takes no action on) all received packets that are either in error or have the wrong value in the acknum field of an acknowledgment packet. Suppose that in such circumstances, rdt3.0 were simply to retransmit the current data packet. Would the protocol still work?

It might not work efficiently.

Explanation:

The function of the protocol rtd3.0 is to transfer data to a receiver from a sender.

As soon as the receiver received the packet transferred by the sender, we respond acknowledge (Ack) to the sender so that sender can confirm the receiver has gotten it.  

The receiver will not send any acknowledgment if the packet he receives are such that bits contain error or not in order.

After that timeout, the packet will be re-transmitted by the sender.

It is then possible the protocol might seem to be inefficient if a packet is sent many times, because other packets will have to wait to sent until the current packet is sent successfully.

The solution to prevent this kind of issue is to allow for the occurrence of premature timeouts.