Which QoS parameter is most relevant when considering the Internet's "best effort" delivery service?

Packet loss is the most relevant QoS parameter in the context of the Internet's "best effort" delivery service because it directly reflects the reliability of the data transmission process. In a best effort delivery system, there are no guarantees that packets sent from the source will reach their intended destination. As a result, some packets may be dropped due to network congestion or other issues, which can lead to data integrity problems and negatively impact the performance of applications, particularly those requiring real-time data, such as voice and video streaming.

While throughput, latency, and bandwidth utilization are also important parameters, they do not capture the fundamental characteristic of the best effort service, which is its inability to ensure successful delivery. Throughput refers to the rate at which data is successfully transmitted, but does not account for failures in delivery. Latency measures the delay in packet transmission, yet does not capture the issue of packet loss. Bandwidth utilization indicates how effectively the available bandwidth is being used but also fails to address the reliability of the delivery itself. Therefore, packet loss stands out as the key parameter relating to the "best effort" nature of Internet services.