Troubleshooting: Citrix Session Slowness – Streaming Audio/Video

Problem:

End users along with management, complain about inconsistent user experience: keyboard and mouse lag, screen pixelation and general sluggishness.

The Solution:

When trying to identify the root cause of a Citrix end user experience issue, you’ll want to start at the XenApp & XenDesktop session display. To access the XenApp & XenDesktop session display, click on View then XenApp & XenDesktop. This page is divided into three areas: App ServersPublished App & Desktops (for Citrix XenApp) environments and Virtual Desktops (for XenDesktop environments). You’ll want to navigate to the applicable section for your environment (Published App & Desktop or Virtual Desktops) in order to troubleshoot further.

These screens are important because they allow you to track the complete user experience through the environment (both past and present), from the login at the endpoint, all the way through the environment back to the underlying infrastructure, and present these data points over the course of the session so you can troubleshoot any issue that takes place during a user’s session.

On the display, you’ll want to find the users who are experiencing issues and click on those sessions to drill down for further details. When troubleshooting slowness, the primary question you’ll usually need to answer is whether the slowness is due to network/connectivity issue or resource constraint. The quickest way to make that determination is by reviewing the user’s Network Latency, ICA RTT, and Connection Speed all which are displayed on the Connection Performance tab, which is the first tab of the drill down.

In reviewing this display, some Goliath users confirm that the end users have enough connection speed, and ICA & Network latency was normal, and ICA RTT wasn’t impeccable, but it wasn’t outside of unacceptable ranges either. When you reach this point where none of the key metrics are standing out as root cause, the next place to turn is the traffic utilization, which is shown in the bottom left hand corner of the tab. If you are seeing high utilization, then this typically means that something the users are doing is causing slowness and load on the connection. In this case, then you’ll want to review the ICA/HDX Channel tab.

The ICA/HDX tab allows you see if there is aberrant behavior in the user’s session consuming the bandwidth. The main data on this display is located in the top right of the screen each channel the user is leveraging for their session is displayed, so we can understand how much traffic is being used to present their session on the end point, this is thinwire.

Or if they are copy/pasting data, or printing a large file, this would get called out in its own separate channel. If users are playing music or video, call center or hospital using VoIP or dictation software, you will see that bandwidth consumption. You’ll also notice that ICA and Connection speed, on the left, are also carried over to this display to help add context to the impact on user experience.

In many cases, especially with Published desktops or VDI, you’ll see thinwire utilization to be high. In some cases, audio bandwidth as well. In one example thinwire utilization might be consuming most of the traffic over 600 k/sec with audio usage steadily at 50 k/sec during the whole session. To identify what was using bandwidth in this example, you can use the Application tab to check to see each application the user had open and the details of the session. In this example, the root cause of the issue might be many users might be streaming video. Streaming music services like Pandora or Amazon music will also produce similar results via their Citrix sessions.

Root Cause:

As mentioned previously, when troubleshooting session slowness issues often you’ll need to determine if network/connectivity or server resources are the root cause. The quickest and easiest way to make that determination is by reviewing the user’s Network Latency, ICA RTT, and Connection Speed – all metrics are displayed within the Connection Performance tab of the end user drill down dialog. However, there are cases where session performance does not manifest in those areas, allowing you to eliminate them as being an issue. The above scenarios demonstrate how what the end user was doing in their session was the cause of their overall session performance.