Assignment 4 (due December 3rd, 2001).

The goal of this project is to write a one-to-many file transfer client-server application.

The server is continuously multicasting the same file over a known multicast group (class D address). The multicasting of the whole file is called a cycle. Clients can start receiving the file at anytime during the cycle. In this case listening has to span portions of two cycles. If the file content changes from one cycle to another the user has to be able to detect it and deliver a consistent file to the user. The file fragments are multicast at fixed intervals of time. The inter-fragment time interval is an argument that can be given to the server. If one fragment is lost the receiver has to wait for the next cycle to receive it.

If the fragments loss rate is high, the application delay can be significantly high. Propose a scheme that can reduce this delay without resulting in a high number of ACKs or NACKs. Implement this scheme.