Monitor client download

Purpose and audience: This tool provides a calculative model to estimate client download time given file size, network bandwidth, and latency. It supports engineers, SREs, product managers, and QA teams evaluating delivery setups and planning capacity for releases. It helps quantify expected download duration, identify bottlenecks, and compare delivery options under modeled conditions.
Core logic: The model uses inputs file_size_bytes, bandwidth_mbps, latency_ms, and optional parallel_connections. Outputs include download_time_seconds, time_to_first_byte_ms, effective_throughput_mbps, and a simple reliability_score. The approach distinguishes basic estimation from advanced modeling via a parallel-fetch factor.
Algorithms & Calculations: Converts file size to bits and computes transfer_time using an adjusted throughput. If parallel_connections > 1, throughput_eff increases by a factor up to a defined cap; download_time = latency + transfer_time. Time-to-first-byte is approximated from latency, while reliability_score reflects input plausibility. This yields actionable planning data without measuring live traffic.
Error & Edge Cases: Missing required inputs triggers errors. Non-positive file sizes or bandwidths are invalid. Extremely high latency with small files may skew estimates; inputs from external data assume stabilized conditions and ignore transient network events.
Localization & Assumptions: Uses metric units (bytes, Mbps, ms) with general Internet-path assumptions. Excludes UI concerns and real-time measurement. Assumes constant network conditions and no server-side throttling. Exclusions include TLS handshakes, DNS times, and CDN cache variability beyond a simple multiplier.
Use cases include pre-release capacity planning, CDN comparison, and download optimization studies for software, games, or media.