Network Connection Information

Diagnostic metrics reported directly by the browser Network Information API.

Understanding the W3C Network Information API

The Network Information API provides web applications with direct telemetry regarding the active connection interface: effective connection type (ECT), estimated round-trip time (RTT), and downlink speed reported directly by the operating system networking stack.

Effective Connection Type (ECT) Profiles

Rather than checking physical Wi-Fi or cellular chip generation, ECT classifies the actual round-trip latency and downlink throughput into standard performance profiles:

  • 4G (Broadband / LTE / 5G): Downlink ≥ 1.4 Mbps, RTT ≤ 273 ms. Instant page loads, smooth 4K/1080p video streaming, real-time multiplayer gaming.
  • 3G: Downlink 270 – 1,400 kbps, RTT 273 – 540 ms. Standard SD video streaming, noticeable page asset delays, casual web browsing.
  • 2G: Downlink 50 – 270 kbps, RTT 540 – 1,400 ms. Heavy image and video timeouts; basic text-only messaging functional.
  • Slow-2G: Downlink < 50 kbps, RTT > 1,400 ms. Severe packet queuing, connection timeouts, high failure rates.

Estimated Downlink & Round-Trip Time

Downlink bandwidth is quantized to increments (typically capped at 10 Mbps by browser vendors to reduce tracking surface area). Real throughput often vastly exceeds this quantized estimate. Estimated RTT measures round-trip transit time in milliseconds, rounded to nearest 25 ms multiples.

Frequently Asked Questions About Connection Telemetry

Why does Estimated Downlink show 10 Mbps when I have 1,000 Mbps gigabit fiber?

The W3C Network Information specification intentionally caps reported downlink bandwidth at 10 Mbps in Chromium browsers. This is a privacy protection measure to prevent malicious ad trackers from fingerprinting your exact broadband tier. To measure your actual multi-gigabit throughput, always use an active throughput benchmark like the WRLDU Speed Test.

What is Save-Data mode?

Save-Data is a browser setting that sends an HTTP Save-Data: on header with web requests. When active, compatible websites serve compressed images, disable video autoplay, and reduce background data fetching to respect cellular data limits.