You can emulate various WAN connection speeds used for HTTP traffic
to determine its effect on response times and throughput.
About this task
You can set a user group to emulate the speed at which HTTP data
is sent and received. By delaying the network uploads and downloads to emulate
a slower network connection, the user group mirrors real-world interaction
with production servers. To emulate line speed:
Procedure
- In the Test Navigator, browse to the schedule and double-click
it. The schedule opens.
- In the schedule, click the user group for which you want to define
a line speed.
- In the Schedule Element Details area, click the Options tab.
- To declare the line speed value:
- Click Enable line speed control.
- Select the actual line speed, or select Custom values to
enter a value.
- Select the desired line speed, or select Custom values to
enter a value, which must be lower than the actual line speed.
Example
If a user group employs multiple agent computers (locations) that
have different real line speed values, to obtain the highest possible accuracy,
we recommend that you divide the user group into smaller user groups so that
each user group contains agents with the same actual line speed value. However,
even if the actual line speeds are different, if they are both much larger
than the desired line speed, then the inaccuracy will be small, and may even
be tolerable.
The following example illustrates this difference. The actual
line speeds are different (100 Mbps and 10 Mbps) but are both much larger
than the desired line speed of 56 Kbps:
The computed line speed delay
for a 5000 byte response where the actual line speed is 100 Mbps and the desired
line speed is 56 Kbps is 706 ms. The computed line speed delay for a 5000
byte response where the actual line speed is 10 Mbps and the desired line
speed is 56 Kbps is 702 ms. In this example, the inaccuracy is only 4 ms.