The GSM Association ( GSMA ) have developed a standard that has been accepted by most of their member operators around the world ( details here ). This allows the intrinsic ‘digital signature’ content of a SIM card to be downloaded ‘Over-The-Air’ ( OTA ). They initially referred to this as ‘Remote SIM Provisioning ( RSP )’ and the chips that facilitate this were known as eUICC’s ( Embedded Universal Integrated Circuit Cards ), however there is a move to get these chips referred to as eSIMs, but in order to avoid confusion on this site they will be referred to as eUICCs.
There are 2 different kinds of eUICC, one that is used in Machine to Machine ( M2M ) devices like connected cars and the other that is used in Consumer devices like mobile phones.
eUICCs offer significant advantages over conventional removable plastic SIM cards. They are smaller, more robust and can be remotely programmed. Their programability means that a single skew of device can be made for several countries and removes the need for expensive field engineers to replace the SIMs in an M2M application.
In order to remotely provision an eUICC it is necessary to have some software loaded in a server which is called ‘Subscription Manager ( SM )’. The Subscription Manager for an M2M eUICC has 2 components, one is called the SM-DP ( Data Preparation ) and the other is called the SM-SR ( Secure Routing ). The SM in the consumer world has combined and enhanced both functions and is called an SM-DP+.
In the consumer world it is preferable to have a server where the end user can discover what mobile services ( profiles ) are available. This is called a Discovery Server ( SM-DS ).