SMS over GSM:
- For the transmission of SMSs in GSM, a special server called SMS Center (SMSC or SC) has to be implemented
- Although the SC does not belong to the GSM network, physically it can be integrated in the same machine as the MSC
- The MSC is in charge of switching functions for all the calls in a certain geographical area.
- The SMS Gateway MSC (SMS-GMSC) is responsible for forwarding the SMS to the destination Visiting MSC (VMSC) and returning the appropriate error information if it’s the case
- In order to reach the SC, the PLMN has to send the message from the VMSC to the MSC where the SC is situated through an entity called SMS-Interworking MSC (SMSIWMSC). It can receive the message from the PLMN and send it to the recipient SC.