.. 제목: 버퍼 팽창 및 BDP 크기 조정 도구
.. 슬러그: buffer-bloat-bdp-tool
.. 날짜: 2026-03-27 12:00:00 UTC
.. 태그: 네트워킹, tcp, bufferbloat, bdp, 성능, 계산기, 도구
.. 카테고리: 계산기
.. 링크:
.. 설명: 대역폭 지연 곱을 계산하고, 버퍼 팽창을 감지하고, 링크 구성에 대한 AQM 권장 사항(fq_codel, CAKE, PIE)을 얻습니다.
.. 유형: 텍스트
<style>
.calc-container { max-width: 900px; margin: 20px auto; padding: 20px; }
.calc-header { margin-bottom: 30px; padding: 25px; background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); border-radius: 12px; box-shadow: 0 4px 6px rgba(0,0,0,0.1); color: white; }
.calc-header h2 { margin-top: 0; color: white; font-size: 28px; margin-bottom: 10px; }
.calc-header p  { margin: 10px 0; opacity: 0.95; font-size: 15px; }
.input-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 15px; margin-top: 20px; }
.input-group { display: flex; flex-direction: column; }
.input-group label { margin-bottom: 8px; font-weight: 600; color: rgba(255,255,255,0.95); font-size: 14px; }
.input-group input, .input-group select { padding: 14px; font-size: 14px; border: 2px solid rgba(255,255,255,0.3); border-radius: 6px; background: rgba(255,255,255,0.95); transition: all 0.3s ease; box-sizing: border-box; }
.input-group input:focus, .input-group select:focus { outline: none; border-color: #4CAF50; background: white; box-shadow: 0 0 0 3px rgba(76,175,80,0.1); }
.button-container { margin-top: 20px; display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; }
.calc-button { padding: 14px 35px; font-size: 16px; background: #4CAF50; color: white; border: none; border-radius: 6px; cursor: pointer; font-weight: bold; transition: all 0.3s ease; box-shadow: 0 2px 4px rgba(0,0,0,0.2); }
.calc-button:hover { background: #45a049; transform: translateY(-1px); box-shadow: 0 4px 8px rgba(0,0,0,0.3); }
.calc-button:active { background: #3d8b40; transform: translateY(0); }
.help-text { margin-top: 15px; font-size: 14px; color: rgba(255,255,255,0.9); background: rgba(0,0,0,0.1); padding: 10px 15px; border-radius: 4px; }
.result-section { background: white; border: 1px solid #e0e0e0; border-radius: 8px; margin-top: 20px; overflow: hidden; box-shadow: 0 2px 4px rgba(0,0,0,0.05); transition: all 0.3s ease; }
.result-section:hover { box-shadow: 0 4px 8px rgba(0,0,0,0.1); }
.section-header { background: linear-gradient(135deg, #4CAF50 0%, #45a049 100%); color: white; padding: 15px 20px; font-size: 18px; font-weight: bold; }
.section-content { padding: 20px; background: #fafafa; }
.result-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 15px; }
.data-row { display: flex; flex-direction: column; padding: 15px; background: white; border-radius: 6px; border-left: 4px solid #4CAF50; box-shadow: 0 1px 3px rgba(0,0,0,0.05); }
.data-label { font-weight: bold; color: #555; font-size: 13px; margin-bottom: 8px; text-transform: uppercase; letter-spacing: 0.5px; }
.data-value { color: #4CAF50; font-family: 'Courier New', monospace; font-size: 20px; font-weight: bold; }
.data-value.small { font-size: 14px; }
.info-box { margin-top: 15px; padding: 15px; background: #e3f2fd; color: #1565c0; border-radius: 8px; border-left: 4px solid #2196F3; font-size: 14px; line-height: 1.6; }
.info-box strong { color: #0d47a1; }
table { width: 100%; border-collapse: collapse; }
th { background: linear-gradient(135deg, #4CAF50 0%, #45a049 100%); color: white; padding: 10px; text-align: left; }
td { padding: 8px 10px; border-bottom: 1px solid #eee; font-size: 13px; }
tr:hover td { background: #f8fff8; }
@media (max-width: 768px) { .input-grid, .result-grid { grid-template-columns: 1fr; } .calc-header h2 { font-size: 22px; } .calc-container { padding: 10px; } }
/* Page-specific — if JS injects .metric-card or .metric-grid classes: */
.metric-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 15px; }
.metric-card { display: flex; flex-direction: column; padding: 15px; background: white; border-radius: 6px; border-left: 4px solid #4CAF50; box-shadow: 0 1px 3px rgba(0,0,0,0.05); }
.metric-label { font-weight: bold; color: #555; font-size: 13px; margin-bottom: 6px; text-transform: uppercase; letter-spacing: 0.5px; }
.metric-value { color: #4CAF50; font-family: 'Courier New', monospace; font-size: 18px; font-weight: bold; }
.result-highlight { color: #4CAF50; font-weight: bold; font-size: 1.2em; }
/* Legacy result-box classes used by JS */
.result-box { background: #f0fff5; border-left: 4px solid #4CAF50; padding: 15px; margin-top: 15px; border-radius: 6px; }
.result-box.warn { background: #fff8e0; border-left-color: #f0a500; }
.result-box.good { background: #f0fff5; border-left-color: #4CAF50; }
.metric-card .val { font-size: 1.3em; font-weight: bold; color: #4CAF50; }
.metric-card .lbl { font-size: 12px; color: #666; margin-top: 4px; }
code { background: #f0f0f0; padding: 2px 5px; border-radius: 3px; font-size: 12px; }
</style>
<div class="calc-container">
<div class="calc-header">
<h2>버퍼 팽창 및 BDP 크기 조정 도구</h2>
<p>대역폭 지연 곱을 계산하고, 버퍼 팽창 조건을 감지하고, AQM 권장 사항을 얻습니다.</p>
<div class="input-grid">
<div class="input-group">
<label>링크 대역폭(Mbps)</label>
<input id="bwMbps" min="0.1" step="any" type="number" value="100"/>
</div>
<div class="input-group">
<label>왕복 시간(ms)</label>
<input id="rttMs" min="0.1" step="any" type="number" value="50"/>
</div>
<div class="input-group">
<label>현재 버퍼 크기(ms, 선택 사항)</label>
<input id="bufMs" min="0" placeholder="0 = skip" step="any" type="number" value="500"/>
</div>
</div>
<div class="button-container">
<button class="calc-button" onclick="calcBdp()">믿다</button>
</div>
</div>
<div class="result-section" id="bdpResultSection" style="display:none">
<div class="section-header">BDP 및 버퍼 팽창 결과</div>
<div class="section-content">
<div id="bdpResult"></div>
</div>
</div>
<div class="result-section">
<div class="section-header">AQM 추천 가이드</div>
<div class="section-content">
<table>
<tr><th>AQM</th><th>최고의 대상</th><th>리눅스 명령</th><th>메모</th></tr>
<tr><td><strong>fq_codel</strong></td><td>범용, 저지연</td>
<td><code>tc qdisc add dev eth0 root fq_codel</code></td>
<td>많은 배포판에서 기본값입니다. 흐름 공정 큐잉 + CoDel</td></tr>
<tr><td><strong>케이크</strong></td><td>홈 라우터, ISP 에지</td>
<td><code>tc qdisc add dev eth0 root cake bandwidth 100Mbit</code></td>
<td>성형을 포함합니다. 대역폭이 제한된 링크에 가장 적합</td></tr>
<tr><td><strong>파이</strong></td><td>케이블 모뎀, DOCSIS</td>
<td><code>tc qdisc add dev eth0 root pie</code></td>
<td>비례 적분 컨트롤러 강화; IETF RFC 8033</td></tr>
</table>
</div>
</div>
<div class="result-section">
<div class="section-header">BDP 참조 테이블</div>
<div class="section-content">
<table id="bdpRefTable">
<tr><th>대역폭</th><th>RTT 10ms</th><th>RTT 50ms</th><th>RTT 100ms</th><th>RTT 300ms</th></tr>
</table>
</div>
</div>
</div>
<script>
const BW_ROWS = [1, 10, 100, 1000, 10000];
const RTT_COLS = [10, 50, 100, 300];

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 = `<td><strong>${label}</strong></td>`;
        RTT_COLS.forEach(rtt => {
            const bytes = bdpBytes(bw, rtt);
            tr.innerHTML += `<td>${fmtBytes(bytes)}</td>`;
        });
        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 = '<div class="result-box"><strong style="color:red">Enter valid bandwidth (&gt; 0 Mbps) and RTT (&gt; 0 ms).</strong></div>';
        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 class="result-box ${cls}" style="margin-top:12px">
            <strong>Buffer analysis:</strong> ${fmtBytes(bufBytes)} buffer (${bufMs} ms at ${bw} Mbps)<br>
            <strong>Buffer / BDP ratio:</strong> ${bufRatio.toFixed(1)}&times;<br>
            ${bloat
                ? `<strong style="color:#b06000">Buffer bloat likely.</strong> Buffer is ${bufRatio.toFixed(1)}&times; the BDP. Latency under load may spike by ~${Math.round(bufMs - rtt)} ms.`
                : `<strong style="color:#155724">Buffer sizing looks reasonable.</strong> Buffer is ${bufRatio.toFixed(1)}&times; the BDP.`}
        </div>`;
    }

    div.innerHTML = `<div class="result-box">
        <div class="metric-grid">
            <div class="metric-card"><div class="val">${fmtBytes(bdp)}</div><div class="lbl">BDP (bandwidth × RTT / 8)</div></div>
            <div class="metric-card"><div class="val">${(bdp/1500).toFixed(0)}</div><div class="lbl">BDP in 1500-byte packets</div></div>
            <div class="metric-card"><div class="val">${bw} Mbps</div><div class="lbl">Link bandwidth</div></div>
            <div class="metric-card"><div class="val">${rtt} ms</div><div class="lbl">RTT</div></div>
        </div>
        <hr style="margin:12px 0;border-color:#c8dfff">
        <strong>AQM Recommendation:</strong> <code>${aqmRec}</code> — ${aqmReason}
    </div>${bloatHtml}`;
}
</script>