Description
1 Assignment Objective The goal of this assignment is to gain experience with both TCP and UDP socket programming in a clientserver environment (Figure 1). You can use any programming language (e.g., Java, Python, c++) to design and implement a client program (client) and a server program (server) to communicate between themselves.
2 Assignment Specifications
2.1 Summary In this assignment, the client will send requests to the server to reverse strings (taken as a command line input) over the network using sockets. This assignment uses a two stage communication process. In the negotiation stage, the client and the server negotiate on a random port (<r_port) for later use through a fixed negotiation port (<n_port) of the server. Later in the transaction stage, the client connects to the server through the selected random port for actual data transfer. Note: The assignment description in the following assumes an implementation in Java.
2.2 Signaling The signaling in this project is done in two stages as shown in Figure 2.
Stage 1. Negotiation using TCP sockets: In this stage, the client creates a TCP connection with the server using Once the server gets this request in the negotiation port, it will reply back with a random port number 2
Stage 2. Transaction using UDP sockets: In this stage, the client creates a UDP socket to the server in 2.3 Client Program (client)
You should implement a client program, named client. It will take the command line inputs: 2.4 Server Program (server)
You should also implement a server program, named server. There are no inputs to the server. Note that, the server must print out the 2.5 Example Execution On host1: server On host2: client <host1/server address 3 Hints You can use the sample codes of TCP/UDP socket programming in Java from the Module 2 slides.
Below are some points to remember while coding/debugging to avoid trivial problems. Use port id greater than 1024, since ports 0‐1023 are already reserved for different purposes (e.g., HTTP @ 80, SMTP @ 25) If there are problems establishing connections, check whether any of the computers running the server and the client is behind a firewall or not. If yes, allow your programs to communicate by configuring your firewall software. Make sure that the server is running before you run the client. Also remember to print the 3
If both the server and the client are running in the same system, 127.0.0.1 (i.e., localhost) can be used as the destination host address. You can use help on Java network programming from any book or from the Internet, if you properly refer to the source in your programs. But remember, you cannot share your program or work with any other student.
4 Procedures
4.1 Due Date The assignment is due on Thursday, June 5th 2014, at midnight (11:59 PM).
4.2 Hand in Instructions Submit all your files in a single compressed file (.zip, .tar etc.) using LEARN in dedicated Dropbox.
You must hand in the following files / documents: Source code files. Makefile: your code must compile and link cleanly by typing “make” or “gmake”. README file: this file must contain instructions on how to run your program, which undergrad machines your program was built and tested on, and what version of make and compilers you are using.
Your implementation will be tested on the machines available in the undergrad environment.
4.3 Documentation Since there is no external documentation required for this assignment, you are expected to have a reasonable amount of internal code documentation (to help the markers read your code).
You will lose marks if your code is unreadable, sloppy, or not inefficient.
4.4 Evaluation Work on this assignment is to be completed individually.
