This section explains how Simbase connectivity works — the concepts underneath the buttons. It answers "what is an APN", "what's the difference between Multi-IMSI and eUICC", "why is my device behind NAT", and similar questions. It does not walk you through configuration; that lives in Getting started and Dashboard.
Read this section when you want to understand something, design a deployment, or make a decision (which SIM technology, which radio access type, whether you need a VPN). Skip it when you just need the steps.
How to use this section
Every article is self-contained, so you can jump straight to the concept you care about — there's no required order. Each one explains the concept, ties it to how Simbase implements it, and links to the relevant Getting started or Dashboard page when there's something to actually do.
If you're new to cellular IoT, there's a suggested reading order further down that builds the concepts up in a sensible sequence.
What's in here
SIM technology
SIM card sizes and form factors — the physical SIM, its sizes (2FF–4FF, MFF2), and how form factor differs from profile.
eSIM — what it is and when to use one — downloadable SIM profiles, and how eSIM differs from eUICC.
Multi-IMSI vs eUICC — the two technologies for multi-operator SIMs, and which to choose.
Connecting to the network
APN explained — what an Access Point Name is and why the wrong one breaks data.
Radio access technologies — 2G through 5G, plus LTE-M, NB-IoT, and LoRa, and which fits your device.
Data roaming and national roaming — how a SIM uses networks beyond its home operator.
Addressing and networking
IP addresses for IoT — how SIMs are addressed on the internet, and IPv4 basics.
Private vs public IP — the difference and why it matters.
Network Address Translation (NAT) — why your device is hidden behind NAT by default.
VPN for IoT — when an encrypted tunnel is worth it and what Simbase supports.
Location and performance
Cell ID and SIM location — how Simbase estimates device location without GPS, and how accurate it is.
Quality of service (QCI) — what to expect from latency and throughput on a roaming SIM, and why.
New to cellular IoT? A suggested reading order
If you're coming from a software or Wi-Fi background and cellular is new, read these in order — each builds on the last:
By the end you'll understand how a device gets online, how it's addressed, why it can or can't be reached from the internet, and what performance to expect.
Looking for steps, not concepts?
Setting up a new account, SIM, or device → Getting started
Using a dashboard feature (coverage, public IPs, SMS, usage limits) → Dashboard
Something isn't working → Troubleshooting
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