VMS is a Voice Mail System provides voice mail services to the post-paid as well as prepaid customers. A typical scenario of voice mail service is that user A establishes a call to user B and if he is not available, the call connects to a voice-mail server and user A leaves a voice message for him. User B is notified by a sms when he has a voice mail delivered to his voice mailbox. Later user B connects to the server and listens to the message.