What is Network Latency?
Network latency is the time delay experienced when data travels between two points in a network, typically measured as the round-trip time (RTT) in milliseconds. It is a key factor in website performance, as higher latency results in slower page loads and degraded user experience for visitors who are geographically distant from the server.
How Does Network Latency Work?
Network latency is caused by several factors including physical distance between the client and server, the number of network hops and routing efficiency, network congestion, and processing time at intermediate devices like routers and switches. A request traveling from New York to a server in London must traverse undersea cables and multiple network nodes, introducing unavoidable delay. Typical latency values range from under 10 milliseconds for local connections to over 200 milliseconds for intercontinental routes.
Reducing network latency is critical for delivering a fast web experience. The most effective strategy is using a CDN to serve content from edge servers located closer to your visitors. Choosing a data center in a geographic region where most of your audience is located also helps significantly. At the protocol level, technologies like HTTP/2 multiplexing, TCP Fast Open, and QUIC reduce latency by minimizing the number of round trips required to establish connections and transfer data.