Packet loss occurs when data packets sent across a network fail to arrive. It is expressed as the percentage of packets lost over a measurement period. Causes include congested links, faulty cables or Wi-Fi interference, overloaded routers and rate-limited or filtered traffic.
Why it matters
TCP detects missing packets and retransmits them, which slows the connection and increases delay, so even 1 to 2 percent loss can noticeably reduce throughput. Real-time traffic such as video calls and games over UDP cannot wait, so the user hears or sees the gap. Sustained loss on a path often looks like intermittent timeouts or "site down from some places".
Example
ping -c 20 example.com
# 20 packets transmitted, 19 received, 5% packet lossTo find where along the path loss starts, use mtr:
mtr -rwc 100 example.comLoss that begins at one hop and continues to the destination indicates a real problem there. Loss at a single middle hop that disappears later is usually just that router de-prioritizing ICMP replies.
Common mistakes
- Judging by a few pings. Collect dozens to hundreds of samples.
- Treating loss at an intermediate
mtrhop as the culprit when later hops are clean. - Ignoring that firewalls and rate limits can drop ICMP while real traffic works.
- Testing only from the server. Loss may exist only on the client's path.
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यह पेज सामान्य जानकारी है, जिसे हमारी संपादकीय टीम ने लिखा है और दस्तावेज़ीकरण बदलने पर अपडेट किया जाता है। सर्वर और प्रदाता अलग-अलग होते हैं, इसलिए बदलाव पहले सुरक्षित तरीके से जाँचें। देखें: संपादकीय नीति और अस्वीकरण.