Two apps at hosts A and B communicate using TCP. The TCP layer at host A sends three segments back-to-back to the TCP layer at host B. The first segment has sequence number 127 and carries 100 bytes of application data. The second and third segment carry 50 and 80 bytes of application data respectively. The receiver has already acknowledged all the bytes up to and including byte number 126 and is now expecting a segment with sequence number 127.

1. What are the sequence numbers in the second and third TCP segment?
2. If the segments arrive in order, and the receiver sends ACKs for each segment, what will be the ACK numbers in the three ACK segments?
3. Assume instead that the segments arrive in reverse order at the receiver, that is, the segment carrying 80 bytes arrives first, then the segment carrying 50 bytes, and finally the segment carrying 100 bytes, and also assume the receiver buffers segments that arrive out of order until all prior segments arrive. If the receiver sends an ACK for each arriving segment, what will be the ACK numbers in the three ACK segments?