HDX Channel Statistics Test

The key factors influencing user experience in a virtual desktop infrastructure are the latencies experienced by the user while connecting to the desktop via ICA and the bandwidth used when a user interacts with a virtual desktop. High latency and excessive bandwidth consumption can often slowdown access to desktops, thereby significantly delaying subsequent user operations. Hence, monitoring the latency and bandwidth usage of the ICA communication channel between the user terminal and the virtual desktops is essential.

The HDX Channel Statistics test auto-discovers the desktops that are brokered by Citrix Xendesktop and the users who are currently connected to each desktop. For each such user, the test monitors the communication between a user and the client desktop, and reports the following:

  • The latency experienced by each user session;
  • The bandwidth used by the incoming and outgoing data/audio/multimedia traffic transacted by the ICA communication channel between each user and virtual desktop;

Using this test, an administrator can identify user sessions that are being impacted by high latency and abnormal bandwidth usage. In addition, the test also reveals the type of traffic that is causing excessive bandwidth usage, thereby providing pointers to how the client configuration can be fine-tuned in order to reduce bandwidth consumption and improve performance.

This test is disabled by default. To enable the test, go to the enable / disable tests page using the menu sequence : Agents -> Tests -> Enable/Disable, pick Microsoft Client Desktop as the desired Component type, set Performance as the Test type, choose the test from the disabled tests list, and click on the < button to move the test to the ENABLED TESTS list. Finally, click the Update button.

Note:

This test will report metrics only for the client desktops that are brokered by Citrix Xendesktop.

Target of the test : A Client Desktop component

Agent deploying the test : An internal agent

Outputs of the test : One set of results for every user who is connected to a client desktop via ICA.

Configurable parameters for the test
Parameter Description

Test Period

How often should the test be executed.

Host

The IP address of the host for which this test is to be configured.

Port

The port to which the specified Host listens

Report By Domain Name

By default, this flag is set to No. This means that, by default, the test will report metrics for each username only. You can set this flag to Yes, to ensure that the test reports metrics for each domainname\username.

Measurements made by the test
Measurement Description Measurement Unit Interpretation

Audio bandwidth input

Indicates the bandwidth used while transmitting sound/audio to this user.

 

Comparing these values across users will reveal which user is sending/receiving bandwidth-intensive sound/audio files over the ICA channel.

To minimize bandwidth consumption, you may want to consider disabling client audio mapping.

Audio bandwidth output

Indicates the bandwidth used while receiving sound/audio from this user.

 

COM bandwidth input

Indicates the average compression ratio for client to server traffic for all the sessions of a user.

 

Comparing these values across users will reveal which user’s COM port is sending/receiving bandwidth-intensive data over the ICA channel.

COM bandwidth output

Indicates the average compression ratio for server to client traffic for all the sessions of a user.

 

Drive bandwidth input

Indicates the bandwidth used when this user performs file operations on the mapped drive on the client desktop.

 

Comparing the values of these measures across users will reveal which user is performing bandwidth-intensive file operations over the ICA channel.

If bandwidth consumption is too high, you may want to consider disabling client drive mapping on the client device. Client drive mapping allows users logged on to a virtual desktop from a client device to access their local drives transparently from the ICA session. Alternatively, you can conserve bandwidth by even refraining from accessing large files with client drive mapping over the ICA connection.

Drive bandwidth output

Indicates the bandwidth used when the virtual desktop performs file operations on the client’s drive.

 

HDX media stream for flash data bandwidth input

Indicates the bandwidth used from this user to virtual desktop for flash data traffic.

Kbps

Comparing the values of these measures across users will reveal which user has been transmitting/receiving bandwidth-intensive flash data.

 

 

 

HDX media stream for flash data bandwidth output

Indicates the bandwidth used from the virtual desktop to this user for flash data traffic.

Kbps

Printer bandwidth input

Indicates the bandwidth used when this user prints to a desktop printer over the HDX channel.

Kbps

Comparing the values of these measures across users will reveal which user is issuing bandwidth-intensive print commands over the ICA channel.

If bandwidth consumption is too high, you may want to consider disabling printing. Alternatively, you can avoid printing large documents over the ICA connection.

Printer bandwidth output

Indicates the bandwidth used when the desktop responds to print jobs issued by this user. 

Kbps

Session bandwidth input

Indicates the bandwidth used from this user to the virtual desktop for a session

Kbps

Comparing the values of these measures across users will reveal which user and which virtual desktop is performing bandwidth-intensive operations for a session.

Session bandwidth output

Indicates the bandwidth used from the virtual desktop to this user for a session.

Kbps

Session compression input

Indicates the compression ratio used from this user to the virtual desktop for a session.

Number

Compression reduces the size of the data that is transacted over the ICA channel.

Comparing the values of these measures across users will reveal which client has been configured with a very low and a very high compression ratio.

In the event of high bandwidth usage over an ICA channel, you can set a higher compression ratio for the corresponding client and thus reduce bandwidth consumption.

Session compression output

Indicates the compression ratio used from the virtual desktop to this user for a session.

Number

Speed screen data channel bandwidth input

Indicates the bandwidth used from this user to the client desktop for data channel traffic.

Kbps

Comparing the values of these measures across users will reveal which user has been transmitting/receiving bandwidth-intensive data channel traffic.

Speed screen data channel bandwidth output

Indicates the bandwidth used from client desktop to this user for data channel traffic.

Kbps

Speed screen multimedia acceleration bandwidth input

Indicates the bandwidth used from this user to the server for multimedia traffic.

Kbps

Comparing the values of these measures across users will reveal which user has been transmitting/receiving bandwidth-intensive multimedia files.

Speed screen multimedia acceleration bandwidth output

Indicates the bandwidth used from the server to this user for multimedia traffic.

Kbps

USB bandwidth input

Indicates the bandwidth used from this user to the virtual desktop for the USB port-related traffic.

Kbps

Comparing the values of these measures across users will reveal which user has been transmitting/receiving bandwidth-intensive USB traffic.

USB bandwidth output

Indicates the bandwidth used from this user to the virtual desktop for the USB port-related traffic.

Kbps

Screen refresh latency - avg

Indicates the average time interval measured at the client between the first step (user action) and the last step (graphical response displayed) of this user's interactions with the server. The value reported is the average of the latencies for all the current sessions of a user.

Secs

This is a measurement of the screen lag that a user experiences while interacting with the XenApp server. In other words, is the latency detected from when the user hits a key unti the response is displayed.

Comparing the value of this measure across users will enable administrators to quickly and accurately identify users who are experiencing higher latency when interacting with the XenApp server.

If both the Screen refresh latency and Client network latency measures report high values, it implies that network slowness is contributing to user-perceived Citrix slowness (i.e., the problem is not due to the Citrix servers, but probably due to the network connection that the user is connecting from - e.g., a wireless WAN).

If Screen refresh latency is high and Client network latency is low, this implies that there is a bottleneck in the Citrix stack that is causing user experience to be poor (e.g., overloaded server or virtual platform, slowness in storage, etc.). Slowness can also occur because of client-side processing delays on the receiver end.

Screen refresh latency - deviation

The latency deviation represents the difference between the minimum and maximum measured latency values for a session. The value reported is the average of the latency deviations for all the current sessions of a user.

Secs

Ideally, the deviation in latencies over a session should be minimum so as to provide a consistent experience for the user.

Screen refresh latency - last

Represents the average client latency for the last request from a user. The latency is measured by the Citrix XenApp server based on packets sent to and from each client during a session - this includes network delay plus server side processing delays. The value reported is the average of the last latencies for all the current sessions of a user.

Secs

A consistently high latency may be indicative of performance degradations with the Citrix XenApp servers. Possible reasons for an increase in latency could be increased network delays, network congestion, server slow-down, too many simultaneous users on the server etc.

Session line speed input

Indicates the average line speed from the client to the server for all the sessions of a user.

Kbps

 

Session line speed output

Indicates the average line speed from the server to the client for all the sessions of a user.

Kbps

 

Bandwidth usage of user's session

Indicates the total bandwidth usage of the sessions of this user.

Kbps

Compare the value of this measure across users to know which user is consuming the maximum bandwidth.

ThinWire bandwidth input

Indicates the bandwidth used from client to server for ThinWire traffic.

Kbps

Typically, ICA traffic is comprised of many small packets, as well as a some large packets. Large packets are commonly generated for initial session screen paints and printing jobs, whereas the ongoing user session is principally comprised of many small packets. For the most part, these small packets are the highest priority ICA data called Thinwire. Thinwire incorporates mouse movements and keystrokes. 

Compare the value of these measures across users to know which user’s keystrokes and mouse movements are generating bandwidth-intensive traffic.

ThinWire bandwidth output

Indicates the bandwidth used from server to client for ThinWire traffic.

Kbps

Seamless bandwidth input

Indicates the bandwidth used from client to server for published applications that are not embedded in a session window.

Kbps

Compare the value of these measures across users to know which user is accessing bandwidth-intensive applications that are not in a session window.

 

Seamless bandwidth output

Indicates the bandwidth used from server to client for published applications that are not embedded in a session window.

Kbps

Resource shares

Indicates the total number of resource shares used by this user.

Number

By comparing the value of this measure across users, you can identify the user who is hogging the resources.