Final answer:
In the GBN protocol, the sender window represents the range of allowable sequence numbers for packets that have been sent but not acknowledged, facilitating flow control and efficient network resource use.
Step-by-step explanation:
In the GBN (Go-Back-N) protocol with a sender window, the window represents the range of allowable sequence numbers that can be assigned to packets that have been sent but not yet acknowledged. This window is a concept in flow control, where the size of the window determines how many packets can be sent at once without receiving an acknowledgment for the first packet in the range. The sender can transmit multiple packets up to the window size, but must wait for acknowledgment before sending new packets beyond the window. This mechanism allows for efficient use of network resources while ensuring that the receiver can process the packets in a manageable order, and in case of lost or corrupted packets, only the unacknowledged ones need to be retransmitted.