Application Performance Management Blog – Shunra Software

In the previous post I presented a new solution that increases the accuracy of load tests by easily adding network conditions to the load generators.

This will be the first in a series of posts that walks through the steps needed to setup a test scenario that includes end user load and network conditions. By the end of this post you will know how to setup a load test that can answer the question: “How will this application perform for a remote user in [Chicago] compared to a local user?” [replace with any remote site that is relevant for your enterprise network]

Our setup includes 2 machines:

1. A LoadRunner controller version 9.5 with a license for the VE Desktop for HP Software. This machine will also serve as a local load generator and is assigned with IP address 172.31.0.143

2. A LoadRunner load generator with the VED for HP injector and VE Reporter for analysis. This machine is assigned with IP address 172.31.0.142 and will simulate the “remote” load generator.

Both machines are physically in our center of excellence lab in Philadelphia, and so is the server under test.

We begin with a simple test scenario that will run the same script from the 2 load generators – 143 will be the local user and 142 will emulate the remote user in Chicago, so we name the 2 groups accordingly:

Next we need to setup the “remote” load generator with the desired network conditions. The WAN emulation conditions are defined on the load generator details dialog box. These details can be accessed by clicking on the Load Generators Icon (marked with the border),

selecting the “remote” load generator in the load generators setup page, and clicking the details button:

You will notice that the Load Generator Details has a WAN Emulation tab. Selecting the tab and checking the Enable WAN Emulation checkbox will allow you to setup the WAN emulation conditions. It is recommended to change the name of the profile to reflect the network conditions, e.g. Chicago, remote site with 512Kbps, Satellite link, etc.

Clicking on the WAN Emulation settings button will open up the following dialog box:

You will notice the 3 setup modes: Basic, Advanced and Professional.

The Basic mode (shown above) allows you to quickly define a network profile based on predefined settings, the example above sets up a network link from a Chicago user to an Atlanta data center with a T1 link during normal business hours.

The advanced mode lets you setup specific network conditions such as latency, packet loss and bandwidth. The Professional mode will be covered in future posts.

Once the desired settings are configured, the test is ready to go. Our test scenario has 1 user from each generator, but the scenario isn’t limited by the number of users (up to the licensed number of virtual users).

The scenario can be saved and run like any other LoadRunner scenario.

Once the test completes, we can invoke the analysis and generate the reports we are looking for (reminder, we want to see the response time between the local user and the user in Chicago). The analysis is triggered by clicking on the LoadRunner analysis button:

By default the analysis results are averaged across all load generators, so we need to group the results by WAN Emulation location which is done in the next 3 steps:

Step 1 – select the transaction response time chart:

Step 2 – Select the Set Filter\Group By option by clicking on (Ctrl T):

And group by emulated location:

Step 3 – We want to present the data as a bar chart, so we select the display options (Ctrl I):

And setup a Bar chart with the following options:

Finally, we get the report we were looking for (below), answering the question:

“How will this application perform for a remote user compared to a local user?”

The local user response time is identified by the transactions with the “No WAN Emulation” suffix, the Chicago user is identified by the transactions with the Chicago suffix (click on the thumbnail to view the large image).

Hope this helps, stay tuned for more use cases and tutorials.

Best,

Amichai