HOMEWORK # 4: Only few of the questions will be selected and graded but you need to answer every question. If you do not answer all the questions, you will not get the full points. Each answer should be marked clearly as Q1 Answer, Q2 Answer, ... and include the questions also. Do not copy & paste from Internet. Write them in your own words.

DUE:

Q1: What is “cumulative acknowledgement”?

Q2: In Selective Repeat protocol, when does a sender retransmit a frame?

Q3: Given a window size W(in bytes), what are the requirements for the buffers in (a) Go Back N and (b) Selective Repeat? Which one is used in current TCP/IP networking?

Q4:

(a)    What is MSS and MTU?

(b)    Assuming an Ethernet connection and 20 byte IP header and 20 byte TCP header, what are the values of MTU and MSS?

(c)    Verify your answer for (b) via Wireshark. Show the screen.

Q5: What is “piggybacked acknowledgment”?

Q6: Discuss two reasons why TCP uses “three way handshake” for connection initiation.. Discuss a reason why TCP uses “four way handshake” for connection termination.

Q7: Point out the difference(s) between Tahoe and Reno versions of TCP’s congestion control.

Q8: What is “fast recovery” in TCP congestion control?

Q9: P26 of Chapter 3—“SYN cookies …..”

Q10: P33 of Chapter 3—"Consider the following plot..."

Q11: There are RFCs that are aimed for improving TCP or UDP. Here are some of them:

(a)    RFC 4340,

(b)    RFC 2960 & 3286

(c)    RFC 3448

Describe, in your own words, what are the main ideas for the improvement,