super.doStart();
Properties properties = configuration.createInitialProperties();
setSipStack(configuration.getSipFactory().createSipStack(properties));
configuration.parseURI();
sipPresenceAgentListener = new SipPresenceAgentListener(this);
configuration.setListeningPoint(
sipStack.createListeningPoint(configuration.getFromHost(),
Integer.valueOf(configuration.getFromPort()).intValue(),
configuration.getTransport()));
provider = getSipStack().createSipProvider(configuration.getListeningPoint());