Problem
ISPs mostly discover in-home WiFi problems reactively, through helpline calls, engineer dispatches and churn. Existing proactive systems detect that a gateway is degrading but not how: a router hidden behind a television needs repositioning, a home saturated by neighbouring 2.4 GHz networks can be fixed remotely by band steering, a boot-looping gateway needs replacing. Treating those as one "degraded" population wastes intervention budget. The missing step is typing: segmenting degraded gateways into recognisable failure archetypes, each mapped to a feasible remediation route, without any hand-labelled fault data.
Design
A cross-sectional weekly snapshot rather than a pooled panel, because the weekly fields are rolling seven-day windows and pooling daily exports would duplicate each gateway into near-identical rows, inflating the apparent sample. The pipeline: data triage with an audit trail, leakage prevention, feature engineering over mixed telemetry, then PCA into a 50-component space. Stage one clusters the full fleet at k=2 to separate healthy from degraded. Stage two re-fits PCA on the degraded population alone and re-clusters it, letting failure types emerge without the healthy mass as a confound. K-Means (k-means++ initialisation) runs against a Gaussian Mixture Model comparator, with DBSCAN excluded on methodological grounds.
Validation Before Interpretation
Internal validity uses Silhouette and Davies-Bouldin scores across candidate cluster counts, computed on a fixed, seeded 25,000-row subsample because Silhouette's quadratic cost is prohibitive at fleet scale. External validity checks cluster assignments against an operational quality-of-experience label that the clustering never saw, using Adjusted Rand Index and Normalised Mutual Information. Temporal stability re-runs the assignment on the following week's snapshot to test whether archetypes persist. Clusters are treated as hypotheses to be validated, not answers.
Findings
The clustering recovers a small set of stable, interpretable failure archetypes with distinct remediation routes, validated externally and across consecutive weeks. Detailed findings and fleet statistics are held back from this page pending partner sign-off; the full dissertation is available on request where confidentiality allows.