Question: In the previous programming assignment, you learned socket programming. In this assignment, you will explore reliable data transfer mechanism utilizing client-server socket communication. We have

In the previous programming assignment, you learned socket programming. In this assignment, you will explore reliable data transfer mechanism utilizing client-server socket communication. We have introduced RDT 3.0

(Chapter 3-part2.ppt, Slide No. 9) in chapter 3. RDT3.0 is a stop-and-wait protocol that uses alternative bit to

realize the reliable data transfer. In this assignment, you will implement client-server communication on two

separate processes similar to what you did in last programming assignment. Then, depending on your preference,

you may implement the RDT sender on the server side and the RDT receiver on the client side or vice versa. The

primary function for the RDT sender is to transfer data message (through socket) to the RDT receiver according to

RDT 3.0 mechanism. The RDT receiver would ACK the message based on RDT 3.0 mechanism. To simplify the

problem, we assume that the sender will always have data to transmit. The data can be defined as a set of phrases

such as the days of the week.

data=["Sunday","Monday","Tuesday","Wednesday","Thursday","Friday","Saturday"]

The sender fetches one of phrases and attaches a proper sequence number to generate a message, which would be

sent by the socket to the receiver side. The sender picks the phrases in order. When reaching the last phrase of

data set, the sender would go back to the first phrase and continue assembling the message. In this way, the sender

would always have data for transfer. As discussed in Chapter 3, the FSM of RDT 3.0 is shown in

Figure 1.

In the previous programming assignment, you learned socket programming. In this assignment,

Because of our assumption of continuous data, the sender no longer needs to wait for data from above. So the

FSM can be simplified. The modified FSM is shown in

Figure 2.

you will explore reliable data transfer mechanism utilizing client-server socket communication. We

As you recall, the RDT 3.0 assumes an unreliable channel between the sender and the receiver. However, the socket

communication is reliable. To simulate the effect of unreliable packet transmission, we add a naughty receiver

function to the receiver side. The FSM of the revised receiver is shown in

Figure 3 and the Naughty_Receiver()

function is shown in

Figure 4. As shown in

Figure 4, instead of just sending an ACK with correct sequence number,

the Naughty_Receiver function has options to send corrupted ACK, not to send ACK or to send ACK with incorrect

sequence number. This function will randomly choose one of the four options (i.e. generate a random number to

choose one of the four options with equal chance) to make the sender experience the different error conditions and

thus go through all the transitions and actions defined in the RDT 3.0. Note: the checksum is not mandatory in this

assignment. When generating the corrupted ACK, the receiver can simply generate a message of corrupted ACK

(as long as the sender understands it is a corrupted ACK).

have introduced RDT 3.0 (Chapter 3-part2.ppt, Slide No. 9) in chapter 3.

RDT3.0 is a stop-and-wait protocol that uses alternative bit to realize the

In this assignment, you will use printout messages to indicate the actions of the sender and the receiver. The sample

printout messages are shown in the appendix. You can define your termination condition. It could be stop after

sending certain number of messages or after fixed number of iterations. Like programming assignment 1, you will

implement both client-server processes on the same server (eustis.eecs.ucf.edu). You can use C/C++, Java, and

Python to program this project. Eustis supports all these programming languages.

Submission:

1. You will submit your source codes

2. You will submit a report to describe the design of your programs, explain how to compile/run your codes

and include screenshots of the running sender and receiver screens (your screens only need to show part

of output messages since the complete set of messages may be much longer). Then, copy and paste the

complete printout messages for both sender and receiver to your report (or to text files). You printout

messages should show all four options (i.e. each option happened at least once) in the

Naughty_Receiver().

3. Since you need to submit several files, please zip all your files into one file and submit through

webcourses.

Appendix: Sample Printout Messages

RDT Sender:

Lets start

Connected by ('127.0.0.1', 57586)

Sender sent a message: Sunday 0

Continue waiting

Timeout. Send the message again

Sender sent a message: Sunday 0

Sender received a valid ACK for 0 , send next message

Sender sent a message: Monday 1

Sender received a corrupted ACK, keep waiting

Continue waiting

Timeout. Send the message again

Sender sent a message: Monday 1

Sender received a valid ACK for 1 , send next message

Sender sent a message: Tuesday 0

Sender received an ACK with wrong sequency number, keep waiting

Continue waiting

Timeout. Send the message again

Sender sent a message: Tuesday 0

Sender received a valid ACK for 0 , send next message

Sender sent a message: Wednesday 1

Sender received a valid ACK for 1 , send next message

Sender sent a message: Thursday 0

Sender received an ACK with wrong sequency number, keep waiting

Continue waiting

Timeout. Send the message again

Sender sent a message: Thursday 0

Sender received a valid ACK for 0 , send next message

Sender sent a message: Friday 1

Sender received a valid ACK for 1 , send next message

Sender sent a message: Saturday 0

Sender received a corrupted ACK, keep waiting

Continue waiting

Timeout. Send the message again

Sender sent a message: Saturday 0

Sender received a valid ACK for 0 , send next message

Sender sent a message: Sunday 1

Continue waiting

Timeout. Send the message again

Sender sent a message: Sunday 1

Sender received a valid ACK for 1 , send next message

Sender sent a message: Monday 0

Sender received an ACK with wrong sequency number, keep waiting

Continue waiting

Timeout. Send the message again

Sender sent a message: Monday 0

Sender received a valid ACK for 0 , send next message

Sender sent a message: Tuesday 1

Sender received a corrupted ACK, keep waiting

Continue waiting

Timeout. Send the message again

Sender sent a message: Tuesday 1

Sender received a valid ACK for 1 , send next message

Sender sent a message: Wednesday 0

Sender received a corrupted ACK, keep waiting

RDT Receiver:

Receiver just correctly received a message: Sunday 0

How do you respond?