.. عنوان: BFD & IP SLA Timer Calculator
.. اسلاگ: bfd-ip-sla-calculator
.. تاریخ: 2026-03-27 12:00:00 UTC
.. برچسب ها: شبکه، bfd، ip-sla، failover، ماشین حساب، ابزار
.. دسته: ماشین حساب
.. لینک:
.. توضیحات: زمان تشخیص خرابی BFD را از فواصل tx/rx و ضریب محاسبه کنید. تأخیر تشخیص BFD در مقابل IP SLA را برای برنامه ریزی شکست فرعی دوم مقایسه کنید.
.. نوع: متن
<style>
/* ── CANONICAL DESIGN SYSTEM ─────────────────────────────────────────────── */
.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, .input-group textarea {
    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; font-family: inherit;
}
.input-group input:focus, .input-group select:focus, .input-group textarea: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; }
.code-block { background: #1e1e2e; color: #cdd6f4; padding: 12px 16px; border-radius: 6px; font-family: 'Courier New', monospace; font-size: 13px; overflow-x: auto; white-space: pre; margin: 8px 0; }
@media (max-width: 768px) {
    .input-grid, .result-grid { grid-template-columns: 1fr; }
    .calc-header h2 { font-size: 22px; }
    .data-value { font-size: 16px; }
    .calc-container { padding: 10px; }
}
/* ── END CANONICAL ────────────────────────────────────────────────────────── */

/* Page-specific */
.badge { display: inline-block; padding: 2px 8px; border-radius: 10px; font-size: 11px; font-weight: bold; }
.badge-fast { background: #d4edda; color: #155724; }
.badge-slow { background: #fff3cd; color: #856404; }
.input-row { display: flex; gap: 15px; flex-wrap: wrap; }
.input-row .input-group { flex: 1; min-width: 160px; }
/* Labels/inputs inside .section-content need dark text (not on purple bg) */
.section-content .input-group label { color: #555; }
.section-content .input-group input,
.section-content .input-group select {
    border: 1px solid #ddd; background: white;
}
.section-content .input-group input:focus,
.section-content .input-group select:focus {
    border-color: #4CAF50; box-shadow: 0 0 0 3px rgba(76,175,80,0.1); background: white;
}
/* JS-injected classes */
.result-box { background: #f8fff8; border-left: 4px solid #4CAF50; padding: 15px; margin-top: 12px; border-radius: 6px; font-size: 14px; line-height: 1.8; }
.result-highlight { font-size: 1.4em; font-weight: bold; color: #4CAF50; }
.compare-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 15px; }
.compare-card { background: white; border: 1px solid #e0e0e0; border-radius: 8px; padding: 15px; border-left: 4px solid #4CAF50; }
.compare-card h4 { margin-top: 0; color: #2d6a2d; }
@media (max-width: 600px) { .compare-grid { grid-template-columns: 1fr; } }
</style>
<div class="calc-container">
<div class="calc-header">
<h2>ماشین حساب تایمر BFD و IP SLA</h2>
<p>محاسبه زمان تشخیص شکست برای جلسات BFD و پروب های IP SLA. گزینه‌های فالوور فرعی و دوم را مقایسه کنید.</p>
</div>
بخش BFD
<div class="result-section">
<div class="section-header">زمان تشخیص BFD</div>
<div class="section-content">
<p style="font-size:13px;color:#666;margin-top:0">زمان تشخیص = حداکثر (دقیقه_tx، مورد نیاز_min_rx) × detect_mult</p>
<div class="input-row">
<div class="input-group">
<label>فاصله حداقل TX مورد نظر (میلی‌ثانیه)</label>
<input id="bfdTx" max="60000" min="50" type="number" value="300"/>
</div>
<div class="input-group">
<label>حداقل فاصله RX مورد نیاز (ms)</label>
<input id="bfdRx" max="60000" min="50" type="number" value="300"/>
</div>
<div class="input-group">
<label>شناسایی ضریب</label>
<input id="bfdMult" max="255" min="2" type="number" value="3"/>
</div>
</div>
<div class="button-container" style="justify-content:flex-start;margin-top:12px">
<button class="calc-button" onclick="calcBfd()">محاسبه BFD</button>
</div>
<div id="bfdResult" style="display:none;margin-top:15px"></div>
</div>
</div>
بخش IP SLA
<div class="result-section">
<div class="section-header">IP SLA Failover Timer</div>
<div class="section-content">
<div class="input-row">
<div class="input-group">
<label>فرکانس IP SLA</label>
<input id="slaFreq" max="604800" min="1" type="number" value="5"/>
</div>
<div class="input-group">
<label>آستانه (شکست های متوالی)</label>
<input id="slaThresh" max="100" min="1" type="number" value="3"/>
</div>
<div class="input-group">
<label>وقفه در هر کاوشگر (میلی ثانیه)</label>
<input id="slaTimeout" max="60000" min="100" type="number" value="2000"/>
</div>
</div>
<div class="button-container" style="justify-content:flex-start;margin-top:12px">
<button class="calc-button" onclick="calcSla()">محاسبه IP SLA</button>
</div>
<div id="slaResult" style="display:none;margin-top:15px"></div>
</div>
</div>
بخش مقایسه
<div class="result-section">
<div class="section-header">مقایسه BFD در مقابل IP SLA</div>
<div class="section-content">
<div class="button-container" style="justify-content:flex-start;margin-top:0">
<button class="calc-button" onclick="calcCompare()">هر دو را مقایسه کنید</button>
</div>
<div id="compareResult" style="display:none;margin-top:15px"></div>
</div>
</div>
جدول از پیش تنظیم استاتیک
<div class="result-section">
<div class="section-header">از پیش تنظیم های معمول تایمر BFD</div>
<div class="section-content">
<table>
<tr><th>نمایه</th><th>حداقل TX/RX (ms)</th><th>ضرب کننده</th><th>زمان تشخیص</th><th>استفاده از مورد</th></tr>
<tr><td>تهاجمی</td><td>50</td><td>3</td><td><span class="badge badge-fast">150 میلی‌ثانیه</span></td><td>مرکز داده، همتایان زیر شبکه یکسان</td></tr>
<tr><td>متعادل</td><td>300</td><td>3</td><td>900 میلی‌ثانیه</td><td>اکثر پیوندهای WAN</td></tr>
<tr><td>محافظه کار</td><td>500</td><td>3</td><td>1500 میلی‌ثانیه</td><td>WAN با تأخیر بالا، ماهواره</td></tr>
<tr><td>آهسته (بدون BFD)</td><td colspan="2">N/A</td><td><span class="badge badge-slow">30-180 s</span></td><td>بازگشت به عقب تایمر نگه داشتن پایین BGP</td></tr>
</table>
</div>
</div>
</div>
<script>
function calcBfd() {
    const tx = parseInt(document.getElementById('bfdTx').value);
    const rx = parseInt(document.getElementById('bfdRx').value);
    const mult = parseInt(document.getElementById('bfdMult').value);
    const div = document.getElementById('bfdResult');
    div.style.display = 'block';
    if (isNaN(tx) || isNaN(rx) || isNaN(mult) || tx < 50 || rx < 50 || mult < 2) {
        div.innerHTML = '<strong style="color:red">Invalid input. Min TX/RX &ge; 50 ms, multiplier &ge; 2.</strong>';
        return;
    }
    const negotiated = Math.max(tx, rx);
    const detectionMs = negotiated * mult;
    const sla = detectionMs < 500 ? 'sub-500ms — excellent for datacenter failover'
        : detectionMs < 1000 ? 'sub-second — suitable for most WAN failover'
        : detectionMs < 3000 ? 'multi-second — suitable for slow WAN/satellite'
        : 'slow — consider reducing intervals if link supports it';
    div.innerHTML = `
        <div class="result-box">
        <span class="result-highlight">${detectionMs} ms</span> detection time<br>
        <strong>Negotiated interval:</strong> ${negotiated} ms (max of TX ${tx} ms, RX ${rx} ms)<br>
        <strong>Multiplier:</strong> ${mult} missed hellos before failover<br>
        <strong>Assessment:</strong> ${sla}
        </div>`;
}

function calcSla() {
    const freq = parseInt(document.getElementById('slaFreq').value);
    const thresh = parseInt(document.getElementById('slaThresh').value);
    const timeout = parseInt(document.getElementById('slaTimeout').value);
    const div = document.getElementById('slaResult');
    div.style.display = 'block';
    if (isNaN(freq) || isNaN(thresh) || isNaN(timeout) || freq < 1 || thresh < 1 || timeout < 100) {
        div.innerHTML = '<strong style="color:red">Invalid input. Frequency &ge; 1 s, threshold &ge; 1, timeout &ge; 100 ms.</strong>';
        return;
    }
    const worstCaseMs = (freq * 1000 * thresh) + timeout;
    const bestCaseMs = (freq * 1000 * (thresh - 1)) + timeout;
    div.innerHTML = `
        <div class="result-box">
        <span class="result-highlight">${(worstCaseMs / 1000).toFixed(1)} s</span> worst-case detection<br>
        <strong>Best case:</strong> ${(bestCaseMs / 1000).toFixed(1)} s (failure occurs just after successful probe)<br>
        <strong>Worst case:</strong> ${(worstCaseMs / 1000).toFixed(1)} s (failure occurs just after failed probe starts)<br>
        <strong>Probe formula:</strong> (frequency &times; threshold) + timeout = (${freq}s &times; ${thresh}) + ${timeout}ms
        </div>`;
}

function calcCompare() {
    const tx = parseInt(document.getElementById('bfdTx').value) || 300;
    const rx = parseInt(document.getElementById('bfdRx').value) || 300;
    const mult = parseInt(document.getElementById('bfdMult').value) || 3;
    const freq = parseInt(document.getElementById('slaFreq').value) || 5;
    const thresh = parseInt(document.getElementById('slaThresh').value) || 3;
    const timeout = parseInt(document.getElementById('slaTimeout').value) || 2000;
    const bfdMs = Math.max(tx, rx) * mult;
    const slaMs = (freq * 1000 * thresh) + timeout;
    const div = document.getElementById('compareResult');
    div.style.display = 'block';
    const faster = bfdMs < slaMs ? 'BFD' : 'IP SLA';
    const ratio = (Math.max(bfdMs, slaMs) / Math.min(bfdMs, slaMs)).toFixed(1);
    div.innerHTML = `<div class="compare-grid">
        <div class="compare-card">
            <h4>BFD</h4>
            <div class="result-highlight">${bfdMs} ms</div>
            <div>Negotiated: ${Math.max(tx, rx)} ms &times; ${mult}</div>
        </div>
        <div class="compare-card">
            <h4>IP SLA</h4>
            <div class="result-highlight">${(slaMs / 1000).toFixed(1)} s</div>
            <div>Worst case: ${freq}s &times; ${thresh} + ${timeout}ms</div>
        </div>
    </div>
    <div class="result-box" style="margin-top:12px">
        <strong>${faster} is faster</strong> by ${ratio}&times; in this configuration.<br>
        ${bfdMs < 1000 ? '<em>BFD at this setting provides sub-second failover not achievable with IP SLA at standard frequencies.</em>' : ''}
    </div>`;
}
</script>