Deploying Multi-Network IoT Connectivity at Scale: A Practical Guide to SGP.32, Multi-IMSI & Satellite NTN

Traditional SIM models, locked to a single network, fall short in today’s IoT environments, where devices require adaptable, resilient connectivity. Whether deployed regionally or globally, static connectivity creates risks: no network redundancy, limited coverage, and added complexity when needs evolve. 

To meet these challenges, modern solutions like multi-IMSI SIMs, SGP.32, and Satellite NTN offer greater control, flexibility, and scale. This paper provides a practical guide to evaluating and deploying these technologies, grounded in real-world implementation insights. 

Connectivity Challenges in IoT Deployments 

IoT devices are deployed in a wide range of environments, including rural, industrial, mobile, and cross-border scenarios, where connectivity needs vary significantly. A single network provider rarely delivers complete or consistent coverage across all deployment zones. Key challenges include: 

Coverage Limitations & Network Failures: Devices relying on a single network provider face coverage gaps and service disruptions.  

Roaming and Cost Constraints: Static roaming can trigger high fees or violate permanent roaming restrictions. 

Operational Complexity: Managing multiple SIM SKUs, contracts, and platforms increases supply chain and integration overhead. 

Performance and Scalability Demands: For latency-sensitive or always-on applications, maintaining consistent performance across networks with differing speed, reliability, and routing remains a challenge. 

Limited Long-Term Flexibility: Legacy SIMs often require physical replacement to change carriers or support new strategies, restricting agility as deployments scale. 

 Compliance Requirements: Regulations may mandate local breakout or in-country data handling. 

Overview of Connectivity Models 

Traditional IoT deployments have used single-IMSI SIMs tied to a specific network operator and static roaming agreements. While straightforward, this model lacks the adaptability required for large-scale or globally distributed use cases. 

To address modern IoT demands, two flexible connectivity architectures have emerged: 

• Multi-IMSI SIMs contain several operator profiles and switch between them based on logic like location or signal quality—providing broader coverage without swapping SIMs.
• SGP.32 enables remote SIM provisioning for IoT devices, using lightweight, asynchronous protocols built for constrained, unattended, or low-power environments. 

In some scenarios, Satellite NTN provides backup connectivity in areas with no terrestrial coverage. It’s not a standalone solution for most use cases but complements terrestrial options. Each model presents trade-offs in complexity, flexibility, and cost. The next sections examine their architectures and deployment factors. 

Multi-IMSI Architecture and Deployment Considerations 

An IMSI (International Mobile Subscriber Identity) is a SIM’s unique identifier, made up of a Mobile Country Code (MCC), Mobile Network Code (MNC), and Subscriber Number (MSIN). Traditional SIMs contain one IMSI tied to a single operator. Multi-IMSI SIMs store multiple IMSIs on the same card, allowing devices to switch between operator profiles based on geography, network conditions, or fallback logic. 

Architecture and Switching Logic 

Multi-IMSI SIMs use a SIM-resident applet to manage and activate the appropriate operator profile. Selection is typically based on predefined logic—such as MCC/PLMN codes, failed registration attempts, or timeout thresholds. More advanced implementations support autonomous switching, where the SIM evaluates network conditions and changes profiles locally, without external systems. 

Switching requires the modem to detach from one network and reattach to another. Devices must remain powered and network-active long enough for this to complete reliably. 

Advantages 

Broader coverage: Access to multiple local networks reduces dependency on roaming. 

Lower cost: Localized connectivity helps control data and roaming charges. 

Faster time to market: Preloaded IMSIs allow for immediate out-of-the-box connectivity. 

Simplified logistics: A single SIM SKU can support multiple regions and operators. 

For many commercial and industrial IoT deployments, Multi-IMSI remains a highly effective and efficient choice, particularly when cost control, fast time to market, and simplified logistics are priorities. 

Deployment Considerations 

The effectiveness of multi-IMSI depends heavily on vendor implementation and device behavior. Engineering teams should evaluate: 

OTA update support: Some SIMs support remote updates; others are fixed at provisioning. 

Custom steering logic: Look for granular control over network selection, fallback behavior, timers, and failover logic. 

Device compatibility and power constraints: Devices must stay powered and network-aware long enough to complete transitions reliably. 

Visibility and diagnostics: Access to real-time network behavior via a centralized connectivity management platform (CMP) is essential for large-scale operations. 

Structural Limitation: Vendor Lock-in 

Most Multi-IMSI SIMs use profiles managed by the provider. While OTA updates may be possible, they are typically limited to the provider’s ecosystem. To use your own carrier agreements or change providers entirely, eUICC functionality is required. A hybrid model, using Multi-IMSI as a bootstrap profile on an eUICC, offers both immediate connectivity and long-term flexibility. 

eUICC and SGP.32: Enabling Scalable, Flexible IoT Connectivity 

SGP.32 is the latest GSMA specification designed to support Remote SIM Provisioning (RSP) for IoT deployments that are resource-constrained, intermittently connected, or lack a user interface. It builds on previous standards like SGP.02 (M2M) and SGP.22 (consumer eSIM) to offer a more scalable, asynchronous, and secure approach tailored for IoT. 

At the core of SGP.32 is the eUICC—an embedded SIM that can host multiple profiles and supports remote provisioning. Its architecture is optimized for constrained devices, enabling profile management through lightweight, asynchronous protocols—well-suited for power-sensitive devices that connect over LPWAN or cellular networks in sleep cycles. 

Key Architectural Components 

The SGP.32 architecture introduces several components designed specifically for the constraints and scale of IoT deployments. 

eUICC: Stores multiple operator profiles and manages lifecycle operations like activation, deactivation, and deletion. 

IPA (IoT Profile Assistant): Facilitates communication between the eUICC and provisioning systems. It can be implemented either on the device (IPAd) or embedded in the eUICC (IPAe), allowing flexibility based on device constraints. 

eIM (eSIM IoT Remote Manager): Orchestrates secure profile downloads and authentication and interacts with the IPA. 

SM-DP+ (Subscription Manager – Data Preparation): Prepares operator profiles and delivers them securely to the eUICC. 

ISD-R / ISD-P: Security domains that manage secure access to eUICC functionality. 

Deployment Considerations and Risks 

While SGP.32 presents a strong foundation for the future of IoT connectivity, there are implementation complexities to consider: 

Regulatory and Security Compliance: Adherence to local laws around data handling and roaming must still be carefully managed. New architectures may introduce unforeseen compliance gaps if not implemented correctly. 

Interoperability Challenges: MNOs may vary in their level of support, which could create fragmentation in service quality across regions. 

Integration Overhead: Switching between providers may require VPN reconfiguration, APN management, and connectivity platform adjustments. 

Cost and Operational Overhead: There are added hosting and switching fees, as well as potential disruptions if CMPs don’t fully support the new profile logic. 

Vendor Lock-In Risks: Without a neutral, interoperable platform, SGP.32 deployments can inadvertently become tied to specific eIM vendors or IPA implementations. 

Hybrid Deployments with Multi-IMSI 

Some providers now combine multi-IMSI as the initial profile on an eUICC with SGP.32-based remote provisioning. This hybrid approach offers the best of both models: instant connectivity on activation, with the flexibility to localize or change operator profiles later via SGP.32. 

Positioning SGP.32 

While Multi-IMSI and SGP.32 both address the limitations of traditional roaming and single-operator lock-in, they serve different needs. SGP.32 excels in deployments that require: 

• Long-term operator flexibility beyond a vendor-managed IMSI library
• Secure, asynchronous, and scalable provisioning across large fleets 

Rather than replacing Multi-IMSI, SGP.32 extends the concept of dynamic, software-defined connectivity, enabling more granular control over SIM lifecycle management. It offers particular value in scenarios where devices are widely distributed, difficult to access, or subject to changing regulatory or operator requirements.

Satellite NTN 

Satellite non-terrestrial networks (NTN), as defined by 3GPP Release 17, are becoming a practical addition to cellular connectivity strategies—particularly for deployments in remote or infrastructure-poor environments. These systems enable fallback connectivity when terrestrial networks are unavailable. 

In most current deployments, satellite NTN access is provided through preloaded IMSIs on dual-mode SIMs. Devices switch to satellite when standard cellular coverage is unavailable, helping maintain connectivity continuity. 

Key Implementation Considerations 

Modem Support: Requires hardware compatible with NTN standards, including relevant RF and protocol features. 

Antenna Requirements: A clear line of sight is often needed. Device enclosures and antenna placement must be designed accordingly. 

Fallback Logic: Switching behavior must be predefined. Work closely with your SIM provider during staging to ensure seamless transition to satellite when needed, and back to cellular when available. 

Satellite NTN is not a universal solution due to cost, latency, and hardware constraints, but it provides meaningful redundancy for critical deployments. 

Technology Selection and Deployment Planning 

Global IoT deployments are inherently complex. Choosing between multi-IMSI, eUICC (SGP.32), or a hybrid model requires aligning device requirements, network conditions, and long-term strategy. 

Key Planning Considerations 

Time-to-Deploy: If your timeline requires rapid scale-up, prioritize solutions that offer immediate out-of-the-box connectivity, such as preloaded multi-IMSI SIMs. If future flexibility outweighs speed, remote provisioning via eUICC may provide longer-term benefits. 

Vendor Lock-In: Consider how tightly your deployment is tied to a specific provider. Multi-IMSI architecture often relies on the provider’s IMSI library. If long-term portability or bringing your own operator agreements is important, ensure your solution includes eUICC support. 

Coverage Flexibility: Confirm your provider supports the countries and network types (e.g., LTE-M, NB-IoT, 5G) relevant to your devices. For multi-IMSI, verify OTA and logic update capabilities to maintain adaptability. 

Compliance and Regulatory Fit: Some markets enforce permanent roaming restrictions or require local data breakout. Confirm whether your connectivity model can localize profiles as needed—either through regional IMSIs or remote provisioning capabilities. 

Latency and Gateway Proximity: Latency-sensitive applications should assess if local breakout is supported for each operator. Gateway placement matters. 

Cost Considerations: SGP.32 has streamlined costs relative to older models, but infrastructure, certification, and integration costs remain. Satellite NTN and multi-IMSI pricing may vary by fallback logic and geography. Consider total cost of ownership. 

Infrastructure and CMP Integration: Choose a CMP that exposes real-time insights into SIM behavior, registration, and fallback across SIM types and operators. 

Scalability and Lifecycle Management: Can your provider support remote SIM updates or large-scale switching logic changes as your footprint evolves? 

Device Capabilities: Validate that hardware and firmware can support your strategy. Multi-IMSI requires reliable detach/reattach cycles; SGP.32 may require IPA and eIM compatibility 

Common Pitfalls to Avoid 

Even with the right strategy, poor execution can introduce costly delays. Watch out for: 

Overlooking Early Connectivity Planning 

Late-stage SIM decisions can create integration delays. Incorporate connectivity needs early in device design. 

Assuming All Vendors Offer the Same Capabilities: Capabilities like OTA updates, fallback behavior, and diagnostics vary widely. Confirm vendor capabilities up front. 

Insufficient Pre-Deployment Testing: Lab validation isn’t enough. Conduct field tests to verify registration, fallback, and CMP behavior under real-world conditions. 

Firmware and Device Incompatibilities: Some SIM operations require the device to remain active long enough to complete transitions or provisioning steps. Ensure device firmware and power profiles are aligned with SIM behavior. 

Lack of Operational Visibility: Without real-time diagnostics, issue resolution becomes reactive. Prioritize vendors with transparent CMP tooling. 

The future of IoT connectivity lies in strategic flexibility, not a one-size-fits-all solution. Whether deploying multi-IMSI, adopting SGP.32, or incorporating Satellite NTN, success depends on early planning, technology alignment, and vendor transparency. With thoughtful integration and robust testing, enterprises can build IoT systems that are resilient, scalable, and ready to meet the challenges of an increasingly dynamic and distributed world.