@Override	
	public void logout(String username, int sentBy) {
		_userStore.remove(username);
		
		notifyUserListChanged();
		
		if((sentBy == ServerInterface.CLIENT) && (backupServer != null)) {
			try {
				backupServer.ping();
				backupServer.logout(username, ServerInterface.SERVER);
			} catch(Exception ex) {
				System.out.println("backup Server not responding");
				resetBackupServer();
			}
		}
	}