Latency is the time it takes for data to travel between two points on a network, typically measured in milliseconds (ms). Key points:
- Types:
- Propagation latency: Time for signal to travel through the medium (depends on distance and speed of signal).
- Transmission latency: Time to push all packet bits onto the wire (packet size / bandwidth).
- Processing latency: Time routers/switches/hosts take to examine and forward packets.
- Queuing latency: Time packets wait in buffers when network devices are congested.
- Common causes of high latency: long physical distance (especially intercontinental links), low bandwidth relative to packet size, overloaded routers or links, wireless interference, poor routing paths, VPNs or proxies, and faulty hardware.
- Impact: Higher latency increases delay for interactive applications (gaming, VoIP, remote desktop) and can reduce throughput for protocols sensitive to round-trip time (e.g., TCP).
- Typical values:
- Local LAN: <1–5 ms
- Same country/region: 10–50 ms
- Cross-continent: 100–300+ ms
- How to measure: Use tools like ping (measures round-trip time), traceroute (shows hops and per-hop latency), and more advanced network monitoring (packet captures, synthetic transactions).
- Ways to reduce latency:
- Use wired connections instead of Wi‑Fi.
- Move servers closer to users (CDNs, edge computing).
- Upgrade bandwidth and hardware (routers, NICs).
- Optimize routing (peering, choose lower-latency paths).
- Reduce packet processing (smaller MTU adjustments, offload features).
- Minimize intermediate proxies/VPNs.
- Prioritize traffic with QoS for latency-sensitive apps.
- Notes on measurement accuracy: Ping uses ICMP which may be deprioritized by devices, so application-level RTT may differ. Traceroute variants use different protocols and may show varying hop behavior.
If you want, I can generate a short explainer for gamers, a troubleshooting checklist, or commands/examples for measuring latency on your system.
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