Courtesy: Infineon
Do you wonder how a traditional SIM works? Today, through this blog, I will talk about the working process of SIM as well as eSIM Remote SIM Provisioning (RSP). So, let’s jump into the techy details.
Working of physical SIM cards
Let’s first take a look at the figure 1 below:
Did you understand anything from this given figure? Well, I’ll explain it now.
Traditional SIM cards were owned and issued by a particular network operator. The Figure 1.1 above showcases that an end user signs up a contract with their selected network operator, they pay the amount for the service and gets the physical SIM card (Case (a)).
Later, the same end user signs-up a contract with a different network operator, pays the service charges and gets the new physical SIM card (Case (b)).
Here, we see that if the end user has to use (a) network or (b) network, he needs to swap the SIM cards on their own.
eSIM remote SIM provisioning
After reading about how physical SIM works, you must be wondering how an eSIM differs from traditional SIMs?
Take a look at the image below:
For remote SIM provisioning, no physical SIM card is required, but an embedded SIM in your handset/device (also called eUICC) – a single eSIM can accommodate and securely store multiple profiles in a single device and each profile comprises operators as well as subscriber’s data.
Let’s see what this figure 2 explains.
At first, in step (a) the end user signs-up a contract with their preferred network operator, pays the required charges, and instead of getting a physical SIM, he receives instructions to connect to operator’s Remote SIM Provisioning system (RSP) [e.g., QR code]. This QR code contains the address of RSP system (SM-DP+ (Subscription Manager Data Preparation) server within the GSMA specifications), which allows the end user to download and install a SIM profile (as shown in step (b)). Once the profile is active, the user can connect to the network successfully (as shown in step (c)).
Important note: In Figure 2, the end user can repeat the process to install more profiles on a single device as shown below in Figure 3. This allows users to switch between profiles 1 and 2 as per their needs.
Some important terms:
Profile: A profile comprises of the operator data related to a subscription. It includes data like – operator’s credentials and provided third-party applications.
eUICC: Embedded Universal Integrated Circuit Card (eUICC) is a secure element in the eSIM solution which can accommodate multiple profiles.
Profiles are always remotely downloaded over-the-air into a eUICC. Although the eUICC is an integral part of the device, the profile remains the property of the operator as it contains items “owned” by the operator (International Mobile Subscriber Identity (ISMI), Integrated Circuit Card ID (ICCID), security algorithms, etc.) and is supplied under licence.
Hence, the eUICC acts as a secure element to store the eSIM Profiles in the device.
We now know how traditional SIM cards VS embedded SIMs (eSIMs) functions differently. In the next blog, I’ll discuss about GSMA M2M solution – The first RSP solution developed by GSM Association (GSMA) for Machine to Machine (M2M) connectivity.
