title: Mobile Location Protocol
text: # Mobile Location Protocol
  
  The Mobile Location Protocol (MLP) is an application-level protocol for receiving the position of Mobile Stations (MS: mobile phones, wireless devices, etc.) independent of underlying network technology.
  
  The MLP serves as the interface between a Location Server and a location-based application. Basic MLP Services are based on location services defined by 3GPP. The Mobile Location Protocol (MLP) is described in LIF TS 101 Specification.
  
  ## Background
  
  The purpose of this technology is to define a simple and secure access method that allows mobile application to query location information from a wireless network, regardless of its underlying network technology and positioning methods.
  
  The MLP can be used by a location-based application to request mobile station location information from a location server (GMLC/MPC or other entity in the wireless network). This protocol has been prepared by Location Interoperability Forum (LIF: Open Mobile Alliance in nowadays) to provide a simple and secure API (Application Programmer’s Interface), but also could be used for other kinds of location servers and entities in the wireless network.
  
  The API is based on XML and is defined to be transported in HTTP or SOAP. Only mapping to HTTP is defined in present days. For security reasons Secure Socket Layer (SSL) or Transport Layer Security (TLS) cryptographic protocols can be used to carry HTTP (HTTPS). Apart from HTTPS Mobile Location Protocol which uses authentication by user and password, the information is carried in header part of MLP message.
  
  ## Features:
  
  Last draft of MLP specification is OMA-TS-MLP v 3.3 from March 2009. Version 3.3 provides these features:
  
  ### Standard Location Immediate Service (SLIS)
  
  Used for requesting the location of one or more Mobile Subscribers (MS). It is used when immediate response is required. Response can be returned in more than one message if the request contained more Mobile Subscribers.
  
  ### Emergency Location Immediate Service (ELIS)
  
  Used for requesting the location of one or more MS involved in an emergency call. Response can be returned in more than one message if the server supports it.
  
  ### Standard Location Reporting Service (SLRS)
  
  This service is initiated by MS by sending Mobile Originated Location Request [TS23271] through wireless network. It is performed when Mobile Subscriber wants an LCS client to receive MS location.
  
  ### Emergency Location Reporting Service (ELRS)
  
  This service is initiated by network when MS initiates or releases emergency call. Report is generated and sent from Location Server to predefined LCS client.
  
  ### Triggered Location Reporting Service (TLRS)
  
  This service is used when LCS client wants to track several MS. Triggers can be timers or MS events like change of location.
  
  ### Historic Location Immediate Service (HLIS)
  
  This service is used to request reporting of historic locations of one MS when large amount of data is expected.
  
  