eG Monitoring
 

Measures reported by WVDTcpTrafficTest

Since most popular applications rely on the TCP protocol for their proper functioning, traffic monitoring at the TCP protocol layer can provide good indicators of the performance seen by the applications that use TCP. The most critical metric at the TCP protocol layer is the percentage of retransmissions. Since TCP uses an exponential back-off algorithm for its retransmissions, any retransmission of packets over the network (due to network congestion, noise, data link errors, etc.) can have a significant impact on the throughput seen by applications that use TCP. This test monitors the TCP protocol traffic to and from an Azure Virtual Desktop, and particularly monitors retransmissions.

Outputs of the test : One set of results for the chosen Session Host / Azure Virtual Desktop.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Segments_recvd Indicates the rate at which segments are received by the virtual desktop. Segments/Sec If the value of this measure is unusually high, then use the detailed diagnosis of the measure to know the source of the unusual traffic.

Note:

Detailed diagnostics will be available only if the TRACE flag and the DETAILED DIAGNOSIS flag of this test are enabled.
Segments_sent Indicates the rate at which segments are sent to clients or other virtual desktops. Segments/Sec  
Retransmits Indicates the rate at which segments are being retransmitted by the virtual desktop. Segments/Sec  
Retransmit_ratio Indicates the ratio of the rate of data retransmissions to the rate of data being sent by the virtual desktop. Percent Ideally, the retransmission ratio should be low (> 5%). Most often retransmissions at the TCP layer have significant impact on application performance. Very often a large number of retransmissions are caused by a congested network link, bottlenecks at a router causing buffer/queue overflows, or by lousy network links due to poor physical layer characteristics (e.g., low signal to noise ratio). By tracking the percentage of retransmission, an administrator can quickly be alerted to problem situations in the network link(s) to the virtual desktop that may be impacting the service performance.