While there is a lot of marketing material discussing the use cases and high level technology comparison, there is not much available on how the overall LTE network architecture would be after NB-IoT upgrade. You’d come across the statement “NB-IoT is just a software upgrade of LTE”, which is merely “over simplifying” the reality as shown in architecture diagram. It is not just an IoT platform and software upgrade but deployment of a new NB-IoT Core, eNB upgrade, OSS upgrade and procurement of new eSIM platform. Additionally integration with other network subsystems such as PCRF, DPI, BSS and possible upgrade of HSS will be quite complex task, which need to be carefully executed.

The new NB-IoT Core or CIoT EPS (standard 3GPP name) offers 2 major CIoT EPS Optimizations:

1. Control Plane CIoT EPS Optimization (Mandatory) - targets transmission of short and infrequent data transmission using Non-Access Stratum (NAS) Signaling Radio Bearer (SRB), avoiding establishment of Data Radio Bearer to save battery life. The data may be routed bi-directionally via SCEF (non-IP Data Only) or via SGW/PGW (IP/non-IP Data) to the IoT platform. 

2. User Plane CIoT EPS Optimization (Optional) - mandates the setup of Data Radio Bearer, which are then used to transport IP/non-IP data via SGW/PGW to the IoT platform. This mechanism is more suitable for connection oriented sessions where sequence of messages need to be exchanged between the server and end device. Additionally, User Plane CIoT Optimization also allows cashing in idle mode to support suspend/resume procedures on Radio/S1 interface. 

Although legacy physical SIM cards (UICC) can be used for NB-IoT, they will no longer provide the flexibility required for IoT use cases. Therefore, GSMA had done a great job finalizing the (defecto) standard for Remote Provisioning of eSIM in May 2016. While eSIM offers distinct advantages as highlighted in Beecham Reaserch, the interoperability testing among different vendors of value chain is critical and time consuming.

Interim solutions like Sierra Wireless AirVantage IoT Platform with Smart (physical) SIM allows late operators binding as well as changing operator, at the cost of binding your solution to specific platform vendor.