title: How to develop my own VLR Number Lookup system using SS7 protocol?
body: <p>I have been in a project which need to know the user last location from VLR(Visitor Location Register). I have seen many online SMS providers offer a special service called HLR Lookup. Some websites offer VLR lookup e.g <a href="http://www.txtnation.com/mobile-messaging/vlr-number-lookup" rel="nofollow">txtnation</a>. VLR lookup may be possible by using the flaw of a poor design choice of the Signaling System No. 7, the global network that powers your calls, in which all GSM operators tap to communicate with each other.</p>
  
  <p>SS7 is really old, and nobody bothered to replace it as technology advanced in the GSM world. It is quite impossible to replace/disable/remove it now because everything is based on it. </p>
  
  <p><a href="https://en.wikipedia.org/wiki/Mobile_Application_Part" rel="nofollow">MAP</a> Signaling is an SS7 protocol that provides an application layer for the various nodes in GSM. <a href="http://www.yate.ro/" rel="nofollow"> Yate </a> is a partial open source implementation of MAP. </p>
  
  <p>But there is not any service for getting VLR response. So would you please advice me  </p>
  
  <ul>
  <li>How could I create my own VLR lookup system?  </li>
  <li>What type of resource I need to develop this system e.g server  </li>
  <li>Is it related to VOIP? Should I need to setup SIP server?  </li>
  </ul>
  
  <p>Thanks a lot in advance.</p>