Latency

The latency of the network is the sum of all delays a message encounters from its point of departure to its point of arrival. The significance of a network's latency varies according to the communication patterns of the application.

Low latency can be particularly important when the message traffic consists mostly of small messages--in such cases, latency will account for a large proportion of the total time spent transmitting messages. Transmitting larger messages can be more efficient on a network with higher latencies.

Parallel I/O operations are less vulnerable to latency delays than some as small-message traffic because the messages transferred by parallel I/O operations tend to be large (often 32 Kbytes or larger).