Hello

This question has already been answered on Chegg however I don't understand its answer.

The TCP sliding window algorithm computes the receiver advertised window as MaxRcvBuffer ((NextByteExpected 1) LastByteRead) and the sender effective window as AdvertisedWindow (LastByteSent LastByteAcked). What are the conditions in which the advertised window on the receiver side and the effective window on the sender side may go to zero?

Thank you