Problem 1:
Consider a TCP connection between host A and host B. Suppose that the TCP segments traveling from host A to host B have source port number x and destination port number y. What are the source and destination port number for segment traveling from host B to host A?
Problem 2:
Suppose Client A initiates a Telnet session with server S. At about the same time, client B also initiates a Telnet session with server S. Provide possible source and destination port numbers for:
- the segment sent from A to S.
- the segment sent from B to S.
- the segment sent from S to A.
- the segment sent from S to B.
- If A and B are different hosts, is it possible that the source port number in the segments from A to S is the same as that from B to S?
- How about if they are the same host?
Problem 3:
UDP and TCP use 1's complement for their checksums. Suppose you have the following three 8-bit words:01010101,01110000,11001100. What is the 1's complement of the sum of these words? Show all work. What is it that UDP takes the 1's complement of the sum, that is, why not just use the sum? With the 1's complement scheme, how does the receiver detect errors? Is it possible that a 1-bit error will go undetected? How about a 2-bit error?
Problem 4:
Consider our motivation for correcting protocol rtd2.1.
Show that this receiver, when operating with the sender shown in above figure, can lead the sender and receiver to enter into a deadlock state, where each is waiting for an event that will never occur.