Question

In the Sliding Window protocol, why does a large window size lead to congestion collapse

Answer 1

TCP provides a reliable transport service between two processes running on a different process. TCP connection consists of a receive buffer, a send buffer, and several variables.

TCP flow control means that TCP will help ensure that the sender is not overwhelming the receiver by sending more packets/segments than it can handle. So, if the receiver posted a large window size that what the network route can handle, then there will be chances of packet losses and there will be retransmission as well. so, the sender can not send all the packets for which Acknowledgment has not been received due to that there will be possibilities to increase more congestion in the network. And the big thing is that the sender cannot be sure about how many packets have been lost.  

Thus, a large window size leads to collapse.