NSA Didn't Break First. Our Assumptions Did. 5G NSA · LTE · architecture assumptions . 7 min read There is a common narrative that early 5G NSA deployments struggled because the architecture was transitional. That framing misses what actually happened. NSA did not introduce new problems. It made existing ones visible at a scale that could no longer be ignored. The LTE anchor had always been treated as the stable, predictable layer. That assumption held when LTE carried LTE traffic and nothing else. Once NR was layered on top, small inconsistencies in the anchor became amplified in ways that no amount of NR-side tuning could fix. Where the assumption failures actually surfaced Fig 1 -- NSA layer interaction: three failure classes tied to LTE anchor assumptions, not NR behavior Each of these failure classes was present in the LTE network before NSA. They had been managed, worked around, or accepted as within-threshold. NSA changed the c...