The HTTP/1.1 / six-connection-cap claim was wrong — it came from the
Schannel curl build that cannot speak HTTP/2. ALPN (openssl s_client)
and .NET HttpClient confirm the portal negotiates h2; the queue is
server-side in the SWA SSR runtime. Doc, index, log and the
GlobalSidebar comment now describe the real mechanism.
Adds the 2026-07-28 outcome section: Standard plan changed nothing
(stratified p50s match, Mann-Whitney p=0.81); prefetch={false} removed
the freezes (worst totalDuration 225s -> 4.9s) and also removed an
accidental keep-alive (~150ms added to cold navigations).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Navbar + GlobalSidebar render the full navigation on every page, so the
App Router's default viewport prefetch fired one ?_rsc= request per
visible link against the SWA runtime (~10.4k requests / 14 days). That
origin serves document, chunks and RSC payloads over HTTP/1.1 (6
connections per origin); when the runtime queued the prefetches (p95
896ms, tail up to 234s), they held every socket and the portal froze
until the queue drained. Measured on the 2026-07-27 17:25 incident:
/admin/presence?_rsc= at 151s while the backend API answered in <2.2s.
All 16 nav links now set prefetch={false}. Every target route is a
client component behind ProtectedRoute that fetches its own data after
mount, so the prefetched RSC payload carried no benefit.
New OKF doc docs/web/portal-navigation-prefetch.md records the full
evidence chain and where browser telemetry lives (separate App Insights
resource, not reachable via MCP query_backend_logs).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Oliver Kieselbach