Exercises

24.1	What does it mean when a system sends an initial SYN segment with a window scale factor of 0?
24.2	If the host `bsdi` in Figure 24.7 supported the window scale option, what is the expected value of the 16-bit window size field in the TCP header from `vangogh` in segment 3? Similarly, if the option were in use for the second connection in that figure, what would be the advertised window in segment 13?
24.3	Instead of fixing the window scale factor when the connection is established, could the window scale option have been defined to also appear when the scaling factor changes?
24.4	At what data rate does sequence number wrap become a problem, assuming an MSL of 2 minutes?
24.5	PAWS is defined to operate within a single connection only. What modifications would have to be made to TCP to use PAWS as a replacement for the 2MSL wait (the TIME_WAIT state)?
24.6	In our example at the end of Section 24.4, why did our sock program output the size of the receive buffer before the line that followed (with the IP addresses and port numbers )?
24.7	Redo the calculations of the throughput in Section 24.8 assuming an MSS of 1024.
24.8	How does the timestamp option affect Karn's algorithm (Section 21.3)?
24.9	If TCP sends data with the SYN segment that's generated by an active open (without using the extensions we described in Section 24.7), what does the receiving TCP do with the data?
24.10	In Section 24.7 we said that without the T/TCP extensions, even if the active open is sent with data and a FIN, the client delay in receiving the server's response is still twice the RTT plus SPT. Show the segments to account for this.
24.11	Redo Exercise 18.14 assuming T/TCP support and the minimum RTO supported by Berkeley-derived systems of one-half second.
24.12	If we implement T/TCP and measure the transaction time between two hosts , what can we compare it to, to determine its efficiency?