.. tiêu đề: Bộ phân tích trung kế Vlan & 802.1Q
.. sên: vlan-trunking-analyzer
.. ngày: 27-03-2026 12:00:00 UTC
.. tags: mạng, vlan, 802.1q, máy tính, công cụ
.. thể loại: Máy tính
.. liên kết:
.. mô tả: Tính toán chi phí hoạt động của đường trục 802.1Q, phân tích danh sách được phép của Vlan và lập kế hoạch tác động MTU thẻ kép QinQ cho thiết kế đường trục mạng.
.. loại: văn bản
<style>
/* ── CANONICAL DESIGN SYSTEM ─────────────────────────────────────────────── */
.calc-container { max-width: 900px; margin: 20px auto; padding: 20px; }
.calc-header {
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}
.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; }
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.calc-button {
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.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; }
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/* ── END CANONICAL ────────────────────────────────────────────────────────── */

.vlan-tag  { background: #4CAF50; color: white; padding: 3px 8px; border-radius: 12px; font-size: 12px; display: inline-block; margin: 2px; }
.vlan-tags { display: flex; flex-wrap: wrap; gap: 4px; margin-top: 8px; }
/* Labels inside .section-content (not on purple bg) need dark text */
.section-content .input-group label { color: #555; }
.section-content .input-group input,
.section-content .input-group select {
    border: 1px solid #ddd; background: white;
}
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.section-content .input-group select:focus {
    border-color: #4CAF50; box-shadow: 0 0 0 3px rgba(76,175,80,0.1); background: white;
}
</style>
<div class="calc-container">
<div class="calc-header">
<h2>Bộ phân tích trung kế Vlan &amp; 802.1Q</h2>
<p>Phân tích danh sách được phép Vlan, tính toán chi phí thẻ và lập kế hoạch tác động của QinQ MTU.</p>
</div>
Phần 1: Trình phân tích cú pháp danh sách được phép của Vlan
<div class="result-section">
<div class="section-header">Trình phân tích cú pháp danh sách được phép Vlan</div>
<div class="section-content">
<div class="input-grid">
<div class="input-group" style="grid-column:1/-1">
<label>Danh sách Vlan (ví dụ: 1-10,20,100-200,4094)</label>
<input id="vlanList" placeholder="1-10,20,100-200,4094" type="text" value="1-10,20,100-200,4094"/>
</div>
</div>
<div class="button-container" style="justify-content:flex-start;margin-top:12px">
<button class="calc-button" onclick="parseVlanList()">Phân tích cú pháp</button>
</div>
<div id="vlanResult" style="display:none;margin-top:15px"></div>
</div>
</div>
Phần 2: Máy tính chi phí thẻ 802.1Q
<div class="result-section">
<div class="section-header">Máy tính chi phí thẻ 802.1Q</div>
<div class="section-content">
<div class="input-grid">
<div class="input-group">
<label>MTU cơ sở (byte)</label>
<input id="baseMtu" max="9216" min="64" type="number" value="1500"/>
</div>
<div class="input-group">
<label>Chế độ gắn thẻ</label>
<select id="tagMode">
<option value="untagged">Không được gắn thẻ (không có chi phí)</option>
<option selected="" value="dot1q">802.1Q (thẻ đơn, +4 byte)</option>
<option value="qinq">QinQ / 802.1ad (thẻ đôi, +8 byte)</option>
</select>
</div>
<div class="input-group">
<label>Tốc độ liên kết (Gbps)</label>
<select id="linkSpeed">
<option value="1">1 Gbps</option>
<option selected="" value="10">10Gbps</option>
<option value="25">25 Gbps</option>
<option value="40">40Gbps</option>
<option value="100">100Gbps</option>
<option value="400">400Gbps</option>
</select>
</div>
</div>
<div class="button-container" style="justify-content:flex-start;margin-top:12px">
<button class="calc-button" onclick="calcOverhead()">Tính toán</button>
</div>
<div id="overheadResult" style="display:none;margin-top:15px"></div>
</div>
</div>
Phần 3: Tham chiếu bố cục byte thẻ QinQ / 802.1ad
<div class="result-section">
<div class="section-header">Lập kế hoạch thẻ đôi QinQ / 802.1ad</div>
<div class="section-content">
<table>
<tr><th>Loại khung</th><th>Byte thẻ</th><th>Loại Ether</th><th>Các trường đã thêm</th></tr>
<tr><td>802.3 không được gắn thẻ</td><td>0</td><td>—</td><td>—</td></tr>
<tr><td>802.1Q (dot1q)</td><td>+4</td><td>0x8100</td><td>TPID (2) + TCI: PCP(3) + DEI(1) + VID(12)</td></tr>
<tr><td>QinQ / 802.1ad</td><td>+8</td><td>0x88A8 bên ngoài</td><td>Thẻ bên ngoài (4) + thẻ 802.1Q bên trong (4)</td></tr>
</table>
</div>
</div>
</div>
<script>
function expandVlanRange(str) {
    const vlans = new Set();
    str.split(',').forEach(part => {
        part = part.trim();
        if (part.includes('-')) {
            const [start, end] = part.split('-').map(Number);
            if (!isNaN(start) && !isNaN(end) && start <= end && start >= 1 && end <= 4094) {
                for (let v = start; v <= end; v++) vlans.add(v);
            }
        } else {
            const v = parseInt(part);
            if (!isNaN(v) && v >= 1 && v <= 4094) vlans.add(v);
        }
    });
    return Array.from(vlans).sort((a, b) => a - b);
}

function compressVlanList(vlans) {
    if (!vlans.length) return '';
    const ranges = [];
    let start = vlans[0], end = vlans[0];
    for (let i = 1; i < vlans.length; i++) {
        if (vlans[i] === end + 1) { end = vlans[i]; }
        else {
            ranges.push(start === end ? `${start}` : `${start}-${end}`);
            start = end = vlans[i];
        }
    }
    ranges.push(start === end ? `${start}` : `${start}-${end}`);
    return ranges.join(',');
}

function parseVlanList() {
    const input = document.getElementById('vlanList').value;
    const vlans = expandVlanRange(input);
    const div = document.getElementById('vlanResult');
    div.style.display = 'block';
    if (!vlans.length) { div.innerHTML = '<strong style="color:red">No valid VLANs found. Valid range: 1\u20134094.</strong>'; return; }
    const tagsHtml = vlans.slice(0, 100).map(v => `<span class="vlan-tag">${v}</span>`).join('') +
        (vlans.length > 100 ? `<span class="vlan-tag">+${vlans.length - 100} more</span>` : '');
    div.innerHTML = `
        <strong>Count:</strong> ${vlans.length} VLANs<br>
        <strong>Normalized:</strong> <code>${compressVlanList(vlans)}</code><br>
        <strong>Range:</strong> VLAN ${vlans[0]} \u2013 ${vlans[vlans.length - 1]}<br>
        <div class="vlan-tags">${tagsHtml}</div>`;
}

function calcOverhead() {
    const baseMtu = parseInt(document.getElementById('baseMtu').value);
    const div = document.getElementById('overheadResult');
    div.style.display = 'block';
    if (isNaN(baseMtu) || baseMtu < 64 || baseMtu > 9216) {
        div.innerHTML = '<strong style="color:red">Invalid MTU. Enter a value between 64\u20139216 bytes.</strong>';
        return;
    }
    const mode = document.getElementById('tagMode').value;
    const speedGbps = parseFloat(document.getElementById('linkSpeed').value);
    const tagBytes = mode === 'untagged' ? 0 : mode === 'dot1q' ? 4 : 8;
    const effectiveMtu = baseMtu - tagBytes;
    const overheadPct = tagBytes > 0 ? (tagBytes / (baseMtu + tagBytes + 18) * 100).toFixed(3) : 0;
    const throughputLoss = tagBytes > 0
        ? ((tagBytes / (baseMtu + 18 + tagBytes)) * speedGbps).toFixed(4)
        : 0;
    div.innerHTML = `
        <strong>Tag overhead:</strong> ${tagBytes} bytes per frame<br>
        <strong>Effective payload MTU:</strong> ${effectiveMtu} bytes (set this on routed sub-interfaces)<br>
        <strong>Frame overhead:</strong> ${overheadPct}% of wire bandwidth consumed by tag bytes<br>
        <strong>Throughput lost at ${speedGbps} Gbps:</strong> ~${throughputLoss} Gbps<br>
        ${tagBytes > 0 ? `<br><em>Recommendation: If running IP over this trunk, set interface MTU to ${effectiveMtu} to avoid fragmentation, or increase the physical MTU to ${baseMtu + tagBytes} if the switch supports jumbo frames.</em>` : ''}`;
}
</script>