CS2911 Week 3, Lab Today Thursday Friday Review Muddiest Point Lab 3 6 May 2019 CS2911 Week 3, Lab Today Review Muddiest Point Lab 3 Lab 4 Muddiest Point Thursday Friday Quiz 2: Encoding in Python 17q1 3-1 1,2,5-9,11-15 17q1 v (started 1_1) Recall the raw representations of the ASCII characters '\r' (CR) and '\n' (LF) v(started 1_1) Recall the raw representations of the ASCII characters A, B, C, D, E, a, b, c, d, e, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 v(started 1_2) Convert a many-digit binary number to its big-endian and little-endian formats v(started 1_2) Give examples of common systems using the big-endian and little-endian formats v Describe the difference between a compiled an an interpreted language v Write a list literal in Python v Write a tuple literal in Python v Index into a tuple or list in Python v Describe the difference between lists and tuples   v Write if-statements in Python v Write a counting (for) loop in Python v Write a sentinel-value (while) loop in Python Write code that manipulates raw bytes in Python using ord(), chr(), int.from_bytes(), and i.to_bytes() Write code that interprets and formats strings using str() and int() (Write exceptions in Python) Declare a Python method Write a string literal in Python Write a bytes literal in Python CS2911 Dr. Yoder Dr. Josiah Yoder

CS2911 6 May 2019 Muddiest Point 3-1 Still feel confused about the differences between TCP and UDP. TCP vs UDP Are we writing the next_bytes method in our lab 3? Lab 3 Will we be expected to actually program a client and server in Python in class/lab Labs Where are all the python code coming from? Are they all from our notes? For example, I did not remember the to_bytes thing. [class 2-1, slide 33] class slides An IPv6 packet walks into a bar. Nobody talks to him joke Does 'host' mean client? terminology What happens if you do not close the socket? sockets Is the code from the slides today sort of what we need to gear towards in our lab code? Dr. Josiah Yoder

CS2911 6 May 2019 Muddiest Point 3-1 Could you walk the class through how to solve and write the Python code in the last exercise we did? Storing 2000 as a 2 byte big-endian raw binary number? encoding in python The great thing about TCP jokes is that you always get them. joke What kind of labs can we expect later in the course? Are we going to get into setting up a sever that can actually handle multiple clients at once? [Yes, but multithreading code is provided] Labs 4-10 Where is the socket located? Built into the application layer, or known by the socket? sockets A TCP packet walks in to a bar and says "I want a beer", barman says "you want a beer?" and TCP packet says "yes, a beer". Dr. Josiah Yoder

CS2911 6 May 2019 Muddiest Point 3-1 Confused as to the way TCP demultiplexes. How is it sure it is ordering all the packets, and how is it sure if a packet hasn't been delivered? Does it require a return? tcp implementation still lost in Python encoding in python? I'd tell you a UDP joke but I don't know if you'd get it joke Could you give more examples of coding in Python? [Please run example code from slides in Python Console] character what does listen_socket.accept() return? sockets from_bytes is still a little off to me, it doesn't seem to return what i expect yet encoding in python Does TCP make things easier for the application side of the client? Dr. Josiah Yoder

Questions about Lab 3? Design process How to implement in Python? CS2911 6 May 2019 Questions about Lab 3? Design process How to implement in Python? Protocol definition What your code should do Receive message Print to screen or write to file … Dr. Josiah Yoder

Questions about Lab 4? CS2911 Dr. Yoder

https://www.polleverywhere.com/free_text_polls/zIp2tH2IVWjXv4H CS2910 5/6/2019 What was the muddiest point? SE-2811 Dr. Josiah Yoder Dr. Josiah Yoder

CS2911 6 May 2019 Acknowledgement This course is based on the text Computer Networking: A Top Down Approach 7th edition Jim Kurose, Keith Ross Addison-Wesley Dr. Josiah Yoder