Is there any mechanism for broadcast messages for every client?

Question

Hi, all
I just wanna to develop such a kind of chatting program. So I just build the communication structure for that. I want to use UDP protocol to send and recieve messages. As we know about that protocol, it does not need connection between server and client, so some packages will be lost. I just used only one DatagramSocket to recieve and send any messages back and forth. And I implemented the client using multithread technique. The problem is that when multiple client sent messages to server, how could server broadcast the specific message to all clients. I am very headache about that. I just used Vector to store diffrent address and port. And when a meesage arrived, I will firstly make ajustment about whether the address and port had been stored, if not, I will add, otherwise I will ignore it. So I think it will be terrible that if thousands of clients connected to the server, how big Vector will be. So I want to know whether the Net package or DatagramSocket provided some kind of mechanism about broadcast messages for every interested client. Thanks. Here is my code below:
ChattingServer.java
* Created on 2005-4-16
* TODO To change the template for this generated file go to
* Window - Preferences - Java - Code Style - Code Templates
// A server that echoes datagrams
import java.net.*;
import java.io.*;
import java.util.*;
* @author Kevin
* TODO To change the template for this generated type comment go to
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public class ChattingServer {
     static final int INPUT = 1066;
     private byte[] buf = new byte[1000];
     private DatagramPacket dp = new DatagramPacket(buf, buf.length);
     private DatagramSocket socket;
     private Vector addrVector, portVector;
     public ChattingServer() {
          try {
               System.out.println("Chatting Server Started......");
               socket = new DatagramSocket(INPUT);
               System.out.println("The status is: " + socket.getBroadcast());
               addrVector = new Vector();
               portVector = new Vector();
               socket.receive(dp);
               addrVector.addElement(dp.getAddress());
               portVector.addElement(new Integer(dp.getPort()));
               System.out.println("The original size of addrVector: " + addrVector.size());
               System.out.println("The original size of portVector: " + portVector.size());
               String first = Transfer.toString(dp);
               System.out.println(first);
               System.out.println("The info: " + dp.getAddress() + ": " + dp.getPort());
               DatagramPacket echo = Transfer.toDatagram(first, dp.getAddress(), dp.getPort());
               socket.send(echo);
               while(true) {
                    socket.receive(dp);
                    System.out.println("A message recieved and prepare for broadcasting.....");
                    for(int i = 0; i < addrVector.size(); i++){
                         if(!((((InetAddress)(addrVector.elementAt(i))).toString() == (dp.getAddress()).toString()) && (((Integer)portVector.elementAt(i)).toString() == (new Integer(dp.getPort())).toString()))) {
                              System.out.println("Before adding element");
                              System.out.println("(InetAddress)(addrVector.elementAt(i)).toString(): " + ((InetAddress)(addrVector.elementAt(i))).toString() + ", dp.getAddress().toString(): " + (dp.getAddress()).toString());
                              System.out.println("(Integer)portVector.elementAt(i).toString(): " + ((Integer)portVector.elementAt(i)).toString() + ", (new Integer(dp.getPort())).toString()" + (new Integer(dp.getPort())).toString());
                              addrVector.addElement(dp.getAddress());
                              portVector.addElement(new Integer(dp.getPort()));
                    String info = dp.getAddress() + ": " + dp.getPort();
                    String rcvd = info + ": " + Transfer.toString(dp);
                    System.out.println(rcvd);
                    System.out.println("The size of addrVector is: " + addrVector.size());
                    System.out.println("The size of portVector is: " + portVector.size());
                    String echoString = Transfer.toString(dp);
                    for(int i = 0; i < addrVector.size(); i++) {
                         InetAddress tempAddr = (InetAddress)addrVector.elementAt(i);
                         int tempPort = Integer.parseInt(portVector.elementAt(i).toString());
                         System.out.println("The port is: " + tempPort);
                         echo = Transfer.toDatagram(echoString, tempAddr, tempPort);
                         socket.send(echo);
          } catch(SocketException e) {
               System.err.println("Can't open socket");
               System.exit(1);
          } catch(IOException e) {
               System.err.println("Communication error");
               e.printStackTrace();
     public static void main(String[] args) {
          new ChattingServer();
ChattingClient.java
* Created on 2005-4-16
* TODO To change the template for this generated file go to
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// Tests the ChattingServer by starting multiple clients, each of which sends datagrams.
import java.lang.Thread;
import java.net.*;
import java.io.*;
* @author Kevin
* TODO To change the template for this generated type comment go to
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class Sender extends Thread {
     private DatagramSocket s;
     private InetAddress hostAddress;
     public Sender(DatagramSocket s) {
          this.s = s;
          try {
               hostAddress = InetAddress.getByName(null);
          } catch(UnknownHostException e) {
               System.err.println("Can not find host");
               System.exit(1);
          System.out.println(" Welcome ChattingDemo..........");
          System.out.println("Please input your name&#65306; ");
     public void run() {
          try {
               String strSent;
               BufferedReader rd = new BufferedReader(new InputStreamReader(System.in));
               String name = rd.readLine();
               while(true) {
                    System.out.print(name + ": ");
                    strSent = rd.readLine();
                    if(strSent == "END") break;
                    s.send(Transfer.toDatagram(strSent, hostAddress, ChattingServer.INPUT));
                    sleep(100);
               System.exit(1);
          } catch(IOException e) {
          } catch(InterruptedException e) {
public class ChattingClient extends Thread {
     private static DatagramSocket s, srv;
     private byte[] buf = new byte[1000];
     private DatagramPacket dp = new DatagramPacket(buf, buf.length);
     public ChattingClient(DatagramSocket s) {
          this.s = s;
     public void run() {
          try {
               while(true) {
                    s.receive(dp);
                    String rcvd = Transfer.toString(dp);
                    System.out.println(rcvd);
                    sleep(100);
          } catch(IOException e) {
               e.printStackTrace();
               System.exit(1);
          }catch(InterruptedException e) {
     public static void main(String[] args) {
          try {
               srv = new DatagramSocket();
          } catch(SocketException e) {
               System.err.println("Can not open socket");
               e.printStackTrace();
               System.exit(1);
          new ChattingClient(srv).start();
          new Sender(srv).start();
}

Answer 1

Hello Amir,
ACS used to tie the license to the MAC address of the machine but I believe Cisco removed that in version 5.1 or 5.2 as users were facing with issues if the MAC changed on a virtual machine. 
Other Cisco products, such as the ASA, Call Manger, and even ISE are a lot more restrictive when it comes to licensing. However, Cisco in general has many products that are licensed on the "honor system" where you are responsible for reporting and paying for everything that you are using. 
Also, I suppose Cisco could audit any companies out there and figure out what the company is using vs what it actually paid for :)
I hope this helps!
Thank you for rating helpful posts!