Latency refers to the time it takes for content to travel from sender to receiver. High latency or delay in content delivery can ruin the user experience and constitute an unacceptable degradation in service quality. For example, consumers expect telephone conversations to have pin drop signal clarity without echoes, delays and other types of distortion. Fiber optic cable networks provide this quality of service, but wireless options, such as microwave and satellite links, typically offer a comparatively inferior service.
Satellite delivery provides the primary means of communications for reaching many nations not served by undersea or backbone terrestrial cables. Satellite telephone communications has high latency, because of the half-second it takes to send a signal up to the satellite, and the additional half-second to receive the downlinked signal. Because telephone conversations often have interruptions and both parties may talk at the same time, satellite latency can generate user frustration with echoes and signal distortion. Satellites rarely handle voice telephone traffic, unless no terrestrial alternative exists.
Operators of broadband networks currently work to reduce network latency and improve quality of service primarily because of competitive necessity and consumer expectations. Many information and communications services require real time, instantaneous delivery of packets so that a “live” conversation can take place. Real time streaming of packets provides the basis for making the Internet a medium for services that parallel radio, television, music jukeboxes, and on demand delivery of video programming.