HostA has established a TCP connection with HostB in a remote network. HostA is sending packets to HostB. Assume we have configured TCP, somehow, to ACK every segment (no ACKing every other segment). Assume that the timeout is the same for all packets. HostBs window size is 20000 bytes. HostB has already received and acknowledged everything sent by HostAs application up to and including byte #2,981. HostA now sends segments of the same application data stream in order:

P: 494 bytes Q: 153 bytes R: 448 bytes

Suppose segments P, Q, and R arrive at Host B in order. What is the acknowledgment number on the segment sent in response to segment R?