Latency

The physical distance and the number of network elements involved (such as routers and communication lines) delay even the smallest data packet significantly. This delay is called latency . In a global network like the Internet, latency can be substantial. When building a client/server solution across a network, these delays may present problems; therefore, additional error checking should be incorporated. For example, latency may cause a database query to exceed the maximum number of seconds allowed for the client to receive a reply. If the environment this solution is running in is susceptible to latency problems, increase the minimum amount of time, or allow the user to cancel (and retry ) the query.

Lesson Summary

Bandwidth is the speed at which data can be transferred from one computer to another. Latency is the delay in data transmission due to the physical distance and number of network elements involved in a transmission. To limit the impact of low bandwidth, consider the following strategies:

• Show text first when displaying a Web page.
• Use alternative text to describe graphics.
• Use separate, smaller images for links instead of one large image map.
• Use interlaced GIFs to return partial results.