Mobile Application Part
The Mobile Application Part is an SS7 protocol that provides an application layer for the various nodes in GSM and UMTS mobile core networks and GPRS core networks to communicate with each other in order to provide services to users. The Mobile Application Part is the application-layer protocol used to access the Home Location Register, Visitor Location Register, Mobile Switching Center, Equipment Identity Register, Authentication Centre, Short message [service center] and Serving GPRS Support Node.
Facilities provided
The primary facilities provided by MAP are:- Mobility Services: location management, authentication, managing service subscription information, fault recovery,
- Operation and Maintenance: subscriber tracing, retrieving a subscriber's IMSI
- Call Handling: routing, managing calls whilst roaming, checking that a subscriber is available to receive calls
- Supplementary Services
- Short Message Service
- Packet Data Protocol services for GPRS: providing routing information for GPRS connections
- Location Service Management Services: obtaining the location of subscriber
Published specification
The Mobile Application Part specifications were originally defined by the GSM Association, but are now controlled by ETSI/3GPP. MAP is defined by two different standards, depending upon the mobile network type:In cellular networks based on ANSI standards plays the role of the MAP a similar protocol usually called IS-41 or ANSI-41. Since 2000 it is maintained by 3GPP2 as N.S0005 and since 2004 it is named .
Implementation
MAP is a Transaction Capabilities Application Part user, and as such can be transported using 'traditional' SS7 protocols or over IP using Transport Independent Signalling Connection Control Part ; or using SIGTRAN.Yate is a partial open source implementation of MAP.
MAP signaling
In mobile cellular telephony networks like GSM and UMTS the SS7 application MAP is used. Voice connections are Circuit Switched and data connections are Packet Switched applications.Some of the GSM/UMTS Circuit Switched interfaces in the Mobile Switching Center transported over SS7 include the following:
- B -> VLR. Most MSCs are associated with a Visitor Location Register, making the B interface "internal".
- C -> HLR Messages between MSC to HLR handled by C Interface
- D -> HLR for attaching to the CS network and location update
- E -> MSC for inter-MSC handover
- F -> EIR for equipment identity check
- H -> SMS-G for Short Message Service over CS
- I -> ME Messages between MSC to ME handled by I Interface
- J -> SCF Messages between HLR to gsmSCF handled by J Interface
- Gr -> HLR for attaching to the PS network and location update
- Gd -> SMS-C for SMS over PS
- Gs -> MSC for combined CS+PS signaling over PS
- Ge -> Charging for Customised Applications for Mobile networks Enhanced Logic prepaid charging
- Gf -> EIR for equipment identity check