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What is latency?
- Authors
- Name
- Skip2 Networks
- Title
- Content Manager
Latency
What is Latency?
Latency refers to the time delay between initiating a request and receiving the first byte of response, essentially measuring how long data takes to travel from point A to point B across a network. Often described as the "round-trip time," latency encompasses all the delays that occur during data transmission, including processing time at servers, routing decisions at network nodes, and the fundamental physical limitation of data traveling at the speed of light through cables and fiber optic lines. Unlike bandwidth, which measures capacity, latency measures speed – you can think of it as the difference between the width of a pipe and how quickly water flows through it.
Network latency becomes particularly critical in today's interactive web applications where users expect immediate responses to their actions. High latency creates noticeable delays that frustrate users, reduce engagement, and can significantly impact business metrics like conversion rates and user satisfaction. Geographic distance plays a major role in latency, as data traveling from New York to Sydney must cover approximately 10,000 miles, creating unavoidable delays even under ideal conditions. This physical reality makes CDNs essential for global applications, as they position content closer to users to minimize the distance data must travel.
Latency Impact Example
An online gaming company notices players in Australia experiencing 300ms latency when connecting to their servers in California, making real-time gameplay nearly impossible due to noticeable delays between player actions and game responses. After deploying CDN edge servers in Sydney and Melbourne, Australian players now experience 15-25ms latency, transforming the gaming experience from frustrating and unplayable to smooth and responsive. This dramatic improvement leads to increased player retention, longer gaming sessions, and higher in-game purchase rates in the Australian market.
Latency Measurement and Benchmarks
| Connection Type | Typical Latency | User Experience |
|---|---|---|
| Local Network | 1-5ms | Imperceptible delay |
| Same City | 5-20ms | Excellent responsiveness |
| Same Country | 20-50ms | Good performance |
| Cross-Continental | 100-300ms | Noticeable delays |
| Satellite | 500-700ms | Significant lag |
Factors Contributing to Latency
- Physical Distance - Speed of light limitations over long distances
- Network Hops - Each router adds processing and queuing delays
- Server Processing - Time required to generate responses
- DNS Resolution - Domain name lookup adds initial delay
- SSL Handshake - Security negotiation creates connection overhead
- Network Congestion - Traffic volume affects routing and queuing times
CDN Latency Optimization Strategies
- Edge Server Placement - Position content geographically closer to users
- Intelligent Routing - Select optimal network paths dynamically
- Connection Optimization - Use HTTP/2, connection pooling, and keep-alive
- Caching Strategies - Serve content from memory rather than disk
- Prefetching - Anticipate and preload likely user requests
Measuring Latency Tools
- Ping - Basic round-trip time measurement
- Traceroute - Shows path and delays at each network hop
- Real User Monitoring - Measures actual user experience latency
- Synthetic Testing - Automated latency testing from multiple locations