Definition
Latency is the time it takes for data to travel from the source to the destination across a network. It is usually measured in milliseconds and reflects the delay between a user action and the system response. Lower latency means faster and more responsive applications, while higher latency can create noticeable lag.
Latency is especially important for real-time services such as video calls, online gaming, and financial trading, where even small delays can affect performance or outcomes.
Advanced
At an advanced level, latency is influenced by factors such as distance between servers, network congestion, routing, and hardware limitations. It is often broken into types, including propagation delay, transmission delay, processing delay, and queuing delay.
Content Delivery Networks and edge computing are commonly used to reduce latency by bringing data closer to users. Monitoring tools track round-trip time, jitter, and packet loss to optimise performance.
Why it matters
- Determines the responsiveness of applications and services.
- Impacts user experience in streaming, gaming, and real-time apps.
- Critical for business systems that require near-instant data transfer.
- Affects the global scalability of cloud and SaaS platforms.
Use cases
- Supporting video conferencing with minimal delay.
- Powering online multiplayer games.
- Reducing lag in financial trading systems.
- Improving performance of global websites with CDNs.
Metrics
- Average latency measured in milliseconds.
- Round-trip time for requests and responses.
- Jitter represents variations in delay.
- Packet loss rates during transmission.
Issues
- High latency leads to slow applications and poor user experience.
- Network congestion or poor routing increases delay.
- Global distance between servers and users adds propagation delay.
- Critical in sectors where split-second decisions matter.
Example
An international e-commerce company reduces latency by deploying servers in multiple regions. With data served closer to customers, page load times improve and conversion rates increase.