UDP Based Chat Application

Objective:

To build a chat application using udp sockets and enable the feature of acknowledgements after every message sent. To develop a dedicated chat application having a server and n number of udp clients. After client and server set up to connect, we need to achieve many clients to communicate through

1. peer-peer

2. File sharing

3. Broadcasting

4. Multicasting

Server: server receives various incoming clients’ requests. It stores the information of the clients i.e. IP address and name in a list. This list is then broadcasted to all the users. Contrary to this, whenever a client logs out, it deletes that particular client entry from its list and updates it accordingly. It also provides a group IP to each multicast group.

Client: It first registers itself by sending its username to the server and starts a thread which receives list of all online users list from server. Each user has an option of establishing a peer to peer communication with any of the

online user, sending a file, creates a room where users selected by him interact with each other i.e. multicasting and sending the same message to all the online users.

1. Peer to Peer Communication:

This module refers to communication between any two clients. Sender sends the request containing its name and a generated random port to the receiver. After receiving the sender’s request at the receiver’s end communication is

established by starting a thread on both sides. When a network gets established between peers, a counter will be initialized at both the sides which will depict the sequence number of the packet. For every packet sent on either side there will be an acknowledgment from the other side which will increase the counter with 1. So if any kind of failure occurs can be identified and a packet may be sent again. For example: If A sends a message with sequence number 10 to B, B will reply back with an acknowledgement with sequence number 11.

2. Multicasting:

When a user wants to create a chat room for multiple users, it sends a request to the server. Server then acknowledges this request by providing a group IP and sends the information about the room to all the concerned users. Now, in this room whenever a user wants to send a message it will be multicast to all the users through the group IP.

3. File Sending:

In this module there would be feature in our chat window which would allow the user to send a file through the network to the other user. When any user wants to send a file to other user a message would appear on the receiver’s side that whether he/she wants to accept it or not. After the acceptance from the receiver whole file would be read and send it to the receiver in the segments of 65,000 bytes and finally at the receiver’s end the segments would be received and stored in a buffer and clubbed according to the sequence number. There would be confirmation message after receiving the file.

4. Broadcasting:

Any of the online users can send the message to all the online users.

The following are the functions of Multi User Chat System :

1) Start the Server: First start the server, then only clients login to chat rooms.

2) Client Login: in this clients enter into chat rooms by entering the nick name server Name and server port number.

3) See all Online People: When ever we entered into chat room then we can see the all the people who are online.

4) Send Public Message: We can send the messages to all the on line people.

5) Send Private Messages: We want to send messages to only a particular user then we change the room from general room.

6) Sending Emote Icons: By Using this Users sending not only text message but also sending emotion icons. They express user feeling very clearly.

7) Ignore Users: we does into want to chat with particular user then user ignores messages send by that user.

8) Allow Users: We allow all Ignored Users by clicking the allow user button.

9) Log out : If Users does into want to chat with any person then sign out from messenger. It is also providing security from unauthorized persons.

Features of the Multi User Chat System:

1) It is very useful to chat peoples with in the network area. 2) We can express out feelings very easily by sending Emoticons.

HARDWARE AND SOFTWARE REQUIREMENTS

Software requirements:

Technologies : core javaOperating System : Windows 2000 Prof/XP.

Hardware requirements:

Processor : Intel Pentium based systemProcessor Speed : 250 MHz to 833MHzRAM : 128 MB to 2 GB