Bandwidth is the amount of data a network connection can carry in a given period, usually measured in bits per second. It describes capacity, not how quickly an individual packet arrives; latency, congestion, packet loss, and the consistency of performance also affect how a network feels and functions.
In cybersecurity, bandwidth matters both for defense and for attack impact. A denial-of-service attack can overwhelm a service by consuming its available network capacity, while defenders monitor traffic to identify unusual spikes or bottlenecks. In distributed systems, including AI clusters, insufficient bandwidth can leave GPUs waiting for data. Measuring network performance alongside workload and storage telemetry helps distinguish a capacity limit from other causes of slowdowns.