This section introduces how to receive and send the IP
packet by the multicast server and provides the functionality of multicast
server through program. A brief description is given bellow.
Description of program:
Here, a graphical layout appears on the screen when
program runs that has two command buttons 'Start' and 'Stop'.
First time 'Start' button is enable and another is disable. When you click
'Start' button, the multicast server functions but button is disable, and the message "Server is started" is displayed in text area. If you want to
stop the server then click on the 'Stop' button then multicast server resume its
function with a message that "Server is stopped". The multicast server receives requests or messages from multicast
client, which has the port number '5000' and IP(Internate Protocol) number
('22.214.171.124', '126.96.36.199', '188.8.131.52', '184.108.40.206'). The server also sends same message to all multicast clients
that are interested for this group
otherwise don't perform these works.
Description of code:
MulticastSocket(int port): This is the constructor of MulticastSocket
class. This class imports from import java.net.*
package and extends the DatagramSocket that can be used for sending or receiving
the multicast IP packets. It is same as DatagramSocket (UDP) and provides an extra facility
to joining 'groups' of multicast hosts on the Internet. The above constructor constructs
multicast socket. It takes integer type port number to bound it.
DatagramPacket(byte buf, int length, InetAddress
address, int port): DatagramPacket is a constructor of DatagramPacket
class. This class extends the Object and imports form import
java.net.* package that can be used for delivering
the connectionless packet so packet delivering is not guarantee at the
destination host. This constructor creates a datagram packet and delivers or
transfers packet length to specified port number at the specified host.