A Short Message Service Center (SMSC) is a network element in the mobile telephone network which delivers SMS messages.
Operation
When a user sends a text message (SMS message) to another user, the message gets stored in the SMSC which delivers it to the destination user when they are available. This is a store and forward operation. The SMSC usually has a configurable time limit for how long it will store the message, and users can usually specify a shorter time limit if they want.

A message may also come from an application, for example voice mail server sending voice mail incoming message alerts. Mobile operators allow businesses to interact with their SMSC to submit the messages in bulk. From SMSC point of view, such applications are called SME (Short Message Entities). In this case the SMSC is responsible for locating SMSC of the destination user and submitting the message there.