Buffer Bloat & BDP Sizing Tool

function bdpBytes(bwMbps, rttMs) { return (bwMbps * 1e6 / 8) * (rttMs / 1000); } function fmtBytes(b) { if (b >= 1e9) return (b/1e9).toFixed(2) + ' GB'; if (b >= 1e6) return (b/1e6).toFixed(2) + ' MB'; if (b >= 1e3) return (b/1e3).toFixed(1) + ' KB'; return Math.round(b) + ' B'; } // Build reference table (function buildRefTable() { const table = document.getElementById('bdpRefTable'); BW_ROWS.forEach(bw => { const tr = document.createElement('tr'); const label = bw >= 1000 ? `${bw/1000} Gbps` : `${bw} Mbps`; tr.innerHTML = `${label}`; RTT_COLS.forEach(rtt => { const bytes = bdpBytes(bw, rtt); tr.innerHTML += `${fmtBytes(bytes)}`; }); table.appendChild(tr); }); })(); function calcBdp() { const bw = parseFloat(document.getElementById('bwMbps').value); const rtt = parseFloat(document.getElementById('rttMs').value); const bufMs = parseFloat(document.getElementById('bufMs').value); const div = document.getElementById('bdpResult'); const section = document.getElementById('bdpResultSection'); section.style.display = 'block'; div.style.display = 'block'; if (isNaN(bw) || isNaN(rtt) || bw <= 0 || rtt <= 0) { div.innerHTML = ''; return; } const bdp = bdpBytes(bw, rtt); const bufBytes = !isNaN(bufMs) && bufMs > 0 ? bdpBytes(bw, bufMs) : null; const bufRatio = bufBytes ? bufBytes / bdp : null; const bloat = bufRatio !== null && bufRatio > 4; // AQM recommendation let aqmRec = 'fq_codel'; let aqmReason = 'general-purpose, excellent for most scenarios'; if (bw < 20) { aqmRec = 'CAKE'; aqmReason = 'low-bandwidth link — CAKE\'s shaping prevents queue buildup'; } else if (bufRatio && bufRatio > 10) { aqmRec = 'CAKE'; aqmReason = 'severe buffer bloat — CAKE + shaping will reclaim latency'; } let bloatHtml = ''; if (bufBytes !== null) { const cls = bloat ? 'warn' : 'good'; bloatHtml = ``; } div.innerHTML = `${bloatHtml}`; }