In networking, packet loss occurs when data packets traveling across a network fail to reach their intended destination. This can be caused by various factors including network congestion, hardware failures, software bugs, or issues with the transmission medium. Packet loss can significantly impact the performance of network services, leading to degraded user experiences, especially for real-time services like video streaming or online gaming. Quantifying packet loss is critical in network management, as it directly influences latency and throughput as well.