# 5G : NSA/SA

**5G** comes in two flavours. **NSA** (Non-Standalone) bolts a 5G radio onto an
existing 4G LTE core — fast to deploy, and the reason early "5G" phones still lean on
LTE for signalling. **SA** (Standalone) is a full 5G core (5GC), unlocking low latency,
network slicing and massive IoT. New Radio (**NR**) uses flexible numerology and can
run from sub-6 GHz up to millimetre-wave.

**Key points:**

* **NSA** = 5G radio + 4G core (transitional); **SA** = end-to-end 5G
* New Radio (**NR**): scalable subcarrier spacing, sub-6 GHz to mmWave
* Peak rates in the **Gbps** range, latency down to a few ms
* A known attack surface at the edge: **NSA redirection** back down to LTE/EDGE

## Quick Access

```{toctree}
:maxdepth: 1
evolution.md
tutorial.md
```