Hi !

My name is Waleed and Im studing Telecommunication engineering in Oslo engineering college. I've got a project in java programming that should be submitted on 01.05.11, the problem is im not that good at java programming :( .

Here is the project, i hope you can help me with this.

Project Part B

The task is to create applications for error-free transmission of data (transmitter and receiver). The program will use UDP for transmission. Error-free transmission here means that all packages should arrive, and the data should be free of bit error,also the data should be stored in the correct order, and that only one copy of each packet to be stored. You should probably have a sequence number, checksum and a timer that provides retransmission. Start with a protocol based on stop-and-wait. If you have time you can also extend to the Go-Back-N Selective Repeat or later. You can simulate the error in the network, by disconnecting form the network. The program should be able to handle a such errors. Make also your own test routines that simulate bit error and / or packet loss.

Minimum Requirements:

The program should divide a file in datagram packets, adds the sequence number and checksum, and waits for acknowledgment before the next packet sent.

Objective: The program should transfer an image without an error even though the connection is down for a while.

Additional (A-candidates): Go-back-N, Selective Repeat. Extra security in the form of authentication, message integrity, Encryption ... The transmitter shall: read data from file divide the contents into smaller packages cause packets sequence number cause packets checksum send packets for the selected protocol This implies in particular that there must be timers that provides retransmission if receipt is not come.

Recipient shall: Checks the checksum, and send a receipt if the package is OK. Controls the sequence number Store data on file (if the sequence number is correct).