There is no doubt that eSIM is going mainstream in the future, the only question is when it happens and how smooth the roll-out will be. One element holding back global eSIM adoption are certainly doubts or missing information about how the hardware used today will manage remote SIM provisioning in the future.
GSM 11.11 specifies mandatory functions, file types, structure and standardizes the physical SIM. Today’s hardware is mostly built according to the GSM 11.11 specification released in 1996, with some updated versions along the way. The standard also defines Application Protocol Data Units (APDU) which are the commands used by the transmission protocol for mapping general functions. Application Protocol Data Units can either be a command APDU or response APDU. Once a response and command APDU pair is set, a new Transport Protocol Data Unit (TPDU) will be created to send and receive data over commonly used protocols like T=0 and T=1.
This has been an essential part for SIMs and cellular hardware modules to communicate, but with today’s high speed and high throughput needs these two protocols can be limited. An eSIM has to be able to fetch new or update existing profiles Over the Air (OTA) that’s why the Bearer Independent Protocol (BIP) was set up and is especially relevant. BIP is bridging the high-speed data channels to the SIM card allowing OTA remote SIM management. The eSIM connects to the SM-SR (Subscription Manager Secure Routing Server) using BIP, where the underlying bearer can be SMS, CAT_TP, or HTTPS. However, it is important to note that the choice of bearer has an impact on accomplishing an eSIM specific task, for example using SMS for profile download can be very slow and unreliable, often resulting in a failed task.
The device or hardware itself needs to fully support BIP for an eSIM to have the possibility to be remotely provisioned. The GSMA has released a new specification targeting consumer and M2M/IoT eSIM. More specific information on the device requirements can be found in GSMA Remote Provisioning Architecture for Embedded UICC Technical Specification (Annex G).
Some of the basic BIP functions that need to be supported.
- Open Channel
- Close Channel
- Receive Data
- Send Data
- Get Channel Status
- Envelop for data download
A list of SIM Application Toolkit (SAT) commands that need to be supported by the device.
- Terminal Profile
- Terminal Response
- Provide Local Information
- Send Short Message
- Poll Interval
- Polling Off
- Timer Management
- Setup Event
- List Envelop for data download by SMS
- Refresh Command
Not all devices support BIP quite yet, some manufacturers are promising software updates in the future that will add the possibility, others are just right now starting to release hardware with BIP. Furthermore modules might need to be configured to allow BIP, SIM ToolKit, or other functionality to work with eSIM. A look at hardware documentation should clear things up.
We are gathering information about BIP supported hardware and also carrying out tests to make sure that 1oT’s eSIM works with today’s devices. What’s more, 1oT is happy to share this information to clear up the confusion about eSIM hardware. The list below is work in progress, and while not complete it will be updated accordingly with new information and test results
BIP supported devices:
If your device is not listed or you are not sure if it supports eSIM make sure to contact us at hacking [at] 1oT.mobi.