Network configuration is a primary factor in the performance of applications. A poorly designed network can slow client activity to unacceptable levels.
You use Network monitoring to determine whether your network is causing a delay in the performance test. You can also determine the problematic network segment.
In a true Web or client/server system, there are many network segments. A single network segment with poor performance can affect the entire system.
The following diagram shows a typical network. To go from the server machine to the Vuser machine, data must travel over several segments.
The Network Delay Time monitor shows the delays for the complete path between the source and destination machines (for example the database server and Vuser host). The graph maps the delay as a function of the elapsed performance test time. Each defined path is represented by a separate line with a different color in the graph.
To measure network performance, the Network monitor sends packets of data across the network. When a packet returns, the monitor calculates the time it takes for the packet to go to the requested node and return. This time is the delay which appears in the Network Delay Time graph.
Note: The delays from the source machine to each of the nodes are measured concurrently, yet independently. It is therefore possible that the delay from the source machine to one of the nodes could be greater than the delay for the complete path between the source and destination machines.
For information about how to set up the network monitoring environment, see Set up the network monitoring environment.
For information about how to configure the Linux source machine for network monitoring, see Configure the Linux source machine for network monitoring.