1. 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
17q ,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

2. 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

3. 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

4. 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

5. 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

6. Questions about Lab 4?
CS2911 Dr. Yoder

7. 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

8. 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