Mobile Application Part - MAP Signaling

MAP Signaling

In mobile cellular telephony networks like GSM and UMTS the SS7 application MAP is used. Voice connections are Circuit Switched (CS) and data connections are Packet Switched (PS) applications.

Some of the GSM/UMTS Circuit Switched interfaces in the Mobile Switching Center (MSC) transported over SS7 include the following:

• B -> VLR (uses MAP/B). Most MSCs are associated with a Visitor Location Register (VLR), making the B interface "internal".
• C -> HLR (uses MAP/C) Messages between MSC to HLR handled by C Interface
• D -> HLR (uses MAP/D) for attaching to the CS network and location update
• E -> MSC (uses MAP/E) for inter-MSC handover
• F -> EIR (uses MAP/F) for equipment identity check
• H -> SMS-G (uses MAP/H) for Short Message Service (SMS) over CS

There are also several GSM/UMTS PS interfaces in the Serving GPRS Support Node (SGSN) transported over SS7:

• 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 (CAMEL) prepaid charging
• Gf -> EIR for equipment identity check