If any mobile user looking for the way how a SMS takes a rout to reach one user's
mobile to another associate mobile user, So user should must aware about SMS architecture which plays a very important role. Anyone can easily find out the way by takes a look to understand GSM, illustrated figure below.
At the beginning, if a user sends a SMS to his buddy,the SMS first deliver from the MS which is know as Mobile Station A to SM-SC(Short Message Service Center) Via the Base Station System (BSS), and then it catch up to the Mobile Station center(MSC) and finally combine with InterworkingMSC(IW-MSC). The use of Short Message Service Center (SM-SC) to carry ahead the SMS message to the GSM network through a definite GSM-MSC called the Short Message Service gateway MSC (SMS-GMSC). The SM-SC is allowed to link with several GSM networks and to several SM-GMSCs in a GSM network. The SMS-GMSC come across the contemporary MSC of the message acceptor and then step ahead the SMS message to that Mobile Station center, pursue the Global System for Mobile Communication (GSM) roaming protocol.The MSC then Publish the SMS through the Base Station System (BSS) to the destination MSB.