A server administrator is investigating reports of slow application performance on a Windows server. Initial analysis shows that CPU and memory usage are within acceptable limits. The administrator suspects the server's network interface may be saturated during peak load. Which of the following Performance Monitor counters provides the MOST direct evidence of network interface saturation?
The correct answer is 'Network Interface: Output Queue Length'. This counter shows the number of packets waiting in the queue to be sent by the network interface card (NIC). A sustained value greater than 2 is a strong and direct indicator that the NIC is a bottleneck and cannot transmit packets as fast as they are being generated.
'Network Interface: Bytes Total/sec' is a useful metric for measuring throughput, but it does not directly indicate saturation on its own. The administrator would need to know the maximum theoretical and practical bandwidth of the interface to determine if the current rate constitutes saturation.
'TCPv4: Connections Established' indicates the number of active TCP connections. A high number of connections does not necessarily mean the network interface is saturated, as each connection could be transmitting very little data.
'Logical Disk: Avg. Disk Queue Length' is a metric for monitoring storage performance, not network performance. It indicates contention for a disk resource.