Lag often refers to delays experienced in computing communications, however it may also apply to written or other forms of communication.
Within computing, Lag refers to the time taken for a packet of data from the sending application to the receiving application. This includes both transit time over the network, and computer processing time at both the source and destination computers.
Whilst in the strictest sense every packet experiences lag, the term lag is implied to refer to noticeable delays to the user caused as a result of extended or unexpected delay. As the time taken for a packet to travel from a server in Europe to a client nearby in the same region is likely to differ from a trip from Europe to the Americas or Asia, it is possible that two users may experience connections to the same server with a different extent of network lag.
The packets are either interrupted along their path by faulty routers, the network cannot handle the number of packets sent/required (see: bandwidth) or the packets pass through an unusually large number of routers before reaching their destination.
Inadequate server processing power
Lag may be experienced where the user submits an unusual request which is not yet cached, or where the reply requires a large amount of processing before it can be sent. This affects multiplayer gaming . The bandwidth of an area which the packets would normally pass through quickly may be disrupted during working hours (for example), thus the packet would need to 'queue' at each router before being sent onwards. A suitable analogy would be the effects of rush hour on everyday road traffic.
Inadequate computer processing power
Even on a fast connection, a slow computer may have a difficult time to process all the data being sent and received while other applications are running, (Ex. Online games and internet Browsers.) Spyware and Peer-to-peer programs hamper the efficiency of both computer and connection integrity, reliability and efficiency in a timely manner.
Slow computers can usually be upgraded very easily in both hardware and software to improve efficency. Stopping other programs such as spyware, trojans, viruses, and Peer-to-peer programs help as well.
Bandwidth - Measure of a connection's maximum data transfer capacity.
Ping - Tool for determining latency with regard to another system.
Avalon - Movie by Mamoru Oshii, in which large parts of the portrayed society play an immense online virtual reality game, features lag as a phenomenon to which players react with bodily symptoms (convulsions, nausea).
