MAP

The Mobile Application Part (MAP), is one of protocols in the SS7 suite and it allows for the implementation of mobile network signaling infrastructure. The foundation behind MAP is to connect the distributed switching elements, called mobile switching centers (MSCs) with a master database, Home Location Register (HLR). The HLR dynamically stores the current location and profile of a mobile network subscriber. HLR is consulted during the processing of an incoming call. Conversely, the HLR is updated as the subscriber moves about the network and is thus serviced by different switches within the network.

MAP messages sent between mobile switches and databases to support user authentication, equipment identification, and roaming are carried by TCAP. In mobile networks when a mobile subscriber roams into a new mobile switching center (MSC) area, the integrated visitor location register (VLR) requests service profile information from the subscriber's HLR using MAP information carried within TCAP messages.

MAP has been evolving as wireless networks grow, from supporting strictly voice, to supporting packet data services as well. The fact that MAP is used to connect Next Generation elements such as the Gateway GPRS Support Node (GGSN) and Serving Gateway Support Node (SGSN) is a evidence to the sound design of the GSM signaling sytem.

Map has several basic fuctions;

Mechanism for a Gateway MSC (GMSC) to obtain a routing number for an incoming call

• Mechanism for an MSC via integrated VLR to update subscriber status and routing number
• Subscriber CAMEL, trigger data to switching elements via the VLR
• Subscriber supplementary service profile and data to switching elements via the VLR