Finally the picture is mine. Took me 30 mins. BTS – Base Transceiver Station (Antenna) BSC – Base Station Controller MSC – Mobile Switching center HLR- Home Location Register VLR – Visitor Location Register SMSC – Short Message Service Center When a user sends an SMS, the request is placed via the MSC. The MSC forwards the SMS to the SMSC where it gets stored. The SMSC queries the HLR to find out...