US Patent 7676570 Determining client latencies over a network

A network latency estimation apparatus for estimating latency in network communications between a server and a client. The apparatus comprises an event observer for observing occurrences of pre-selected events. The events associated with the communication occurring at the server. A logging device associated with the event observer for logging into a data store the occurrence of the events together with respective time information. A latency estimator associated with the logging device for using the logged occurrences with the respective time information to arrive at an estimation of a client's latency for the communication.