WHY DOES LATENCY MATTER?
Latency (ping/RTT) is the round-trip time for a packet. Even fast connections feel sluggish with high latency. Database queries on a 100ms link can turn a 50-query page load into a 5-second wait. Use this guide to set SLAs and troubleshoot performance issues.
Network Latency Guide — Acceptable Ping Times by Application Type
This comprehensive network latency guide provides acceptable, ideal and poor latency thresholds for every major application type — from VoIP and online gaming to database queries and file transfers. Use this reference when designing networks, troubleshooting performance complaints, writing SLAs, or explaining to stakeholders why latency matters as much as bandwidth.
Understanding RTT vs One-Way Latency
RTT (Round Trip Time) — measured by the ping command — is the total time for a packet to travel from source to destination and back. One-way latency is approximately half the RTT and is what matters for applications like VoIP where the ITU G.114 recommendation specifies a maximum one-way delay of 150ms for acceptable voice quality. Tools like ping, traceroute, mtr and smokeping help identify and monitor latency.
How to Measure and Diagnose Network Latency
- ping — Basic RTT measurement. Use
ping -c 100for statistical analysis of packet loss and jitter. - traceroute / tracert — Shows the latency at each router hop, identifying where delays are introduced.
- mtr (My Traceroute) — Combines ping and traceroute for continuous monitoring with packet loss statistics per hop.
- iperf3 — Measures actual TCP/UDP throughput and jitter between two endpoints.
- smokeping — Long-term latency monitoring with graphical visualisation of trends and packet loss.
Causes of High Network Latency
- Geographic distance — The unavoidable speed-of-light delay. Use CDNs and edge computing to bring content closer to users.
- Network congestion — Too much traffic for the available bandwidth causes queuing delays. Resolve with QoS, bandwidth upgrades or traffic shaping.
- Routing inefficiency — Suboptimal BGP paths can add unnecessary hops. Work with your ISP or use direct peering.
- Buffer bloat — Excessive buffering in routers and modems introduces latency during congestion. Resolve with CoDel or FQ-CoDel queue management.
- Wireless interference — Wi-Fi adds variable latency due to channel contention, interference and retransmissions. Use wired connections for latency-sensitive applications.