MSC:

Abbreviation for Mobile services Switching Center. The MSC is part of the GSM Network Switching Subsystem (NSS)
  • The MSC is actually a digital switch that has been upgraded to suit the requirements of a mobile network environment. In other words: The digital exchanges within the PSTN can also be used as MSC.
  • Accordingly, companies like ALCATEL or SIEMENS could use their already existing hardware (S12, E10, EWSD) as MSC.
  • In GSM, the MSC takes care of the resource management on the A-interface towards the BSC and it is responsible for call processing.
  • Also, the MSC is suited to process a handover procedure between two and even three MSCs.
  • A special function is given to the Gateway-MSC (G-MSC) which is an MSC that provides access to external networks. Note that in a PLMN not every MSC needs to be a G-MSC.
  • Other MSC's might incorporate more specialized functions for the processing of short messages (SMS-IW-MSC / SMS-G-MSC). See in the figure below.

Figure 1: The Difference between SMS-IW-MSC and SMS-G-MSC