Month: May 2012

Citrix Cloud Gateway, a wrap-up so far

/ Bram Wolfs / 1 Comment

Citrix Cloud Gateway, a wrap-up so far

Table of contents :

1 : Introduction
2 : Cloud Gateway Editions
3 : Storefront services
4 : Access Gateway services
5 : Cloud Gateway Enterprise and the Access Gateway Universal License
6 : Cloud Gateway Express and the Platform License
7 : Webinterface V.S. Receiver for Web
8 : Conclusion

1 : Introduction

In this blog post I wanted to talk about Citrix Cloud Gateway, as you may already know, Cloud Gateway will replace Citrix Webinterface and Webinterface will go end of live in 2015. Webinterface has grown into a key component in almost every Citrix environment, and it is a so called “proven technology” product. Webinterface is great in providing access to XenApp and XenDesktop environments in many different ways and  different scenarios, but that is also its limitation, there is no possibility to integrate it with Cloud services like follow-me-data or SaaS applications. This is why Citrix made a new product from scratch, called Cloud Gateway. This blog post is a wrap-up so far about Cloud Gateway, because Citrix is working hard on the product things in this blog post may be very soon changed or outdated.

2 : Cloud Gateway Editions

There are currently 2 editions of Cloud Gateway :

Cloud Gateway Enterprise

Cloud Gateway Enterprise is the paid version and provides the following features :

– Access to XenApp and XenDesktop (through Storefront)
– ShareFile integration (new in version 2.0)
– Single Sign On (SSO) and account provisioning for Web and SaaS applications through AppController
– Mobile (native) app management + remote wipe (new in version 2.0)
– Access Gateway Universal License included

Cloud Gateway Express

Cloud Gateway Express is free for XenApp and XenDesktop customers and provides access to XenApp and XenDesktop and Merchandising services only.This version will be the direct replacement of Webinterface.
With Merchandising services you can manage the complete Citrix Receiver (and other plugins) life cycle.

3 : Storefront Services

As you can see in the above pictures Storefront is one of the key components in Cloud Gateway, it’s the broker for all the services behind it and provides a SSO experience for the users.
Storefront provides access to XenApp and XenDesktop in the following 3 ways :

1 : Access through the Native Receiver (Self Service plugin)
2:  Access through StoreWeb (Receiver for Web)
3:  Access through Legacy mode (PNAgent)

The native receiver can be configured with a provisioning file (.cr file which is XML based) downloaded from the Receiver for Web or distributed by Email or something like that.
To make the internal access to Storefront more clear I made the following drawing :

Every login point is used by different type of client devices, some Receivers (older Thinclients, Android devices and Iphones) still uses the legacy mode (PNAgent). But newer Receivers will talk to Storefront directly and not using Legacy mode anymore.

4 : Access Gateway Services

Another key component in Cloud Gateway is the Access Gateway, there are 2 types of Access Gateways that can be used with Cloud Gateway:

1: Access Gateway VPX (with or without advanced controller software)
2: Access Gateway Enterprise (Netscaler VPX\MPX)

Whether you go for Cloud Gateway Express or Enterprise you need to buy a Access Gateway Platform license for one of this Access Gateways. The platform license will give you unlimited access to XenApp and XenDesktop, this is called ICA proxy. With ICA proxy you are allowed to land on the Webinterface and launch a XenApp and/or a XenDesktop session but you cannot use any advanced features of the Access Gateway (for example Clientless Access, VPN plugin, EPA scans, etc), if you want to use this features you need to purchase a Access Gateway Universal License per concurrent user (included with Cloud Gateway Enterprise license).
In Access Gateway you can choose between the following logon point\virtual server modes :

1: Basic Mode (ICA Proxy only) (Platform license needed)
2: Smart Access Mode (Advanced Features) (Platform license + Universal License needed)

To make this more clear I made a drawing how the access to storefront looks like with the Access Gateway Enterprise edition :

As you can see the Netscaler will check, if it is correctly configured, the type of Receiver based on expression filters and HTTP headers. Netscaler will then contact Storefront the right way depending on the Receiver type. With Access Gateway VPX you cannot configure this expression filters, Access Gateway VPX works with Receiver for Web, but I have not yet seen this working with the native receiver from the outside.
My guess is that Citrix will enable this in a feature release of Access Gateway VPX.

5: Cloud Gateway Enterprise and the Access Gateway Universal License

If you purchase Cloud Gateway Enterprise you are also entitled to use the Access Gateway Universal License, i think this is a logical step because Cloud Gateway Enterprise leverages the clientless access and VPN features of the Access Gateway, for example Appcontroller can be configured with keywords to start the VPN plugin and for access to Storefront clientless access is used.

6: Cloud Gateway Express and the Platform License (ICA Proxy)

As you may have noticed you need clientless access when you want to use the Native Receiver through Access Gateway, though it works on a VIP in basic mode the documentation says that you need a VIP in Smart Access mode to make this work. I can imagine that Citrix is going to allow one of the following when using Cloud Gateway Express with the platform license only :

1: Only allow landing on the Receiver for Website (same as ICA proxy using Webinterface)
2: Allow access for all type of Receivers, but only for use with XenApp and XenDesktop

Option 2 is most preferred imho! 😉

6 : Webinterface V.S. Receiver for Web

First : Webinterface cannot be directly compared to Storefront, because Storefront enables a lot more other features then Webinterface (SSO to other services, Application subscription, more advanced HA, etc.) But if we compare Webinterface with the Receiver for Website, it is safe to say that Webinterface has still a lot more features. Thomas Koetzing made a list of missing features here, but I am certain that Citrix is working hard on this feature list, remember that they are only at version 1.1 so there is a lot more to come.

The total redesign has also some very positive points, for example a big plus of Storefront is that it includes a new user authentication method which directly queries Active Directory rather than the existing double-hop Web Interface process where user credentials are sent from the Web Interface server to the XML broker who then negotiates authentication with the Domain Controller.

7: Conclusion

I think Cloud Gateway and Storefront have a lot of potential, it gives the user a true single logon experience with all of the applications and data they need in one place on almost every device. Integration is the key here as more and more companies are starting to use Cloud services,  Cloud Gateway aggregates and secures this services into one logical logon point with the same look and feel on every device.

On the down side, Storefront is still missing a lot of features compared to Webinterface, if you already installed Storefront and walked through the console you were probably done in 30 seconds 😉 not much to customize there. This is why Storefront is not yet a tight fit in scenarios with special needs and requirements. I hope Citrix will make it as flexible and customizable as Webinterface is today in feature releases!

If you want to know more about Fine-tuning Adaptive Display, please read my previous blog post and follow me on twitter or subscribe on this blogsite if you want to be notified when a new blog post is available! thanks!

Please note that the information in this blog is provided as is without warranty of any kind, it is a mix of own research and information provided by Citrix.

Adaptive Display, what’s in the game? And do we need to fine-tune?

/ Bram Wolfs / 17 Comments

Make sure to also check this blogpost about a very handy tool named Remote Display Analyzer

In this blog post I wanted to talk about Adaptive Display, this new HDX feature is now available in both XenDesktop 5.5\5.6 and XenApp 6.5 (through a hotfix), Adaptive Display is the successor of the highly successful Progressive Display SpeedScreen technology, and it’s switched on by default. It’s an awesome technology because it is auto adopting to changes in the available bandwidth.

There is not so much information in the Citrix Edocs about fine tuning Adaptive Display, this is mainly because it’s auto-tuning and in various blog posts from Citrix they are saying the following :

“Progressive Display requires creating complex policy configurations to get it right making it a hard to use feature. Adaptive Display eliminates the need for such complex configurations and provides a fantastic out-of-the-box experience, making it zero configurations for Citrix Administrators”

Ok that’s fine by me, so we do not have to create complex policies anymore for LAN and WAN use cases, because it will detect the available bandwidth and adjusts accordingly. Super!
But what is exactly going on inside the Thinwire channel?
Before I go further, let’s summarize the default settings that are adjustable within Adaptive Display :

Adaptive Display Setting

Default Value
Max frames per second 24
Target Minimum Frame rate 10
Minimum Image Quality Normal
Moving Image Compression On (Enables or Disables Adaptive Display)
Extra Color Compression Default Off and enabled when bandwidth is below 8192 KBps
Heavyweight Compression Default Off
Lossy Compression level Default Medium, the default threshold is unlimited

* Note:  At this time, not all Adaptive Display policies can be configured using the XenApp 6.5 AppCenter console. Use Windows Group Policy Editor (gpedit.msc) instead.

Ok so now we know what settings are in the game of Adaptive Display, how are this settings come together? To make this more clear I made some drawings and explanations.

Let’s begin with the Extra Color Compression setting,  Color Compression takes advantage of the fact that the human eye is less sensitive to color information (Chroma) than luminance (Luma). When images are encoded with less color information, the bandwidth savings are huge yet the human eye still sees a very satisfactory picture. Most of today’s digital cameras use this technique to save on storage space. Extra Color Compression is turned on by Adaptive Display when the default threshold of 8192 KBps is reached, let’s picture this default behavoir :

Ok moving on to the Minimum Image Quality setting, this setting sets the JPEG quality floor.
In other words, this is the minimal acceptable JPEG quality, the following minimum quality levels can be set :

Minimum Image Quality

JPEG Quality
Ultra High 80 (highest image quality, lowest Compression)
Very High 55
High 30
Normal (Default) 20
Low 15 (Lowest image quality, Highest Compression)

The Lossy Compression level set’s the starting JPEG Quality, Adaptive Display adjusts the JPEG quality between the starting point to the Minimum Image Quality based on the bandwidth available to try to keep the frame rate from decreasing. The default starting JPEG Quality is 55 (Medium). Ok let’s picture this combination :

Notice that the default Lossy Compression level is set to Medium and the threshold to enable Lossy compression is set to 2147483647 KBps (unlimited), which means that this setting is always on.
The following Lossy Compression levels can be configured :

Lossy Compression Level

Starting JPEG Quality
High 25
Medium (Default) 55
Low 80
None 80 (Lossless)

Ok now we know what the default settings are and how the frame rate and compression is dynamically adjusted by Adaptive Display.  So what about this default settings, should we change it or leave it alone?
As usual it depends on the use case 🙂 but read on….

There is a great tool from Citrix called HDX Monitor, this tool lets you see all the HDX aspects in an active ICA session. If you start the HDX Monitor (with the default settings in place) you will see the following screen :

Ok looks good, but what’s that big red cross? Let’s find out :

Error : Image compression is not tuned to the available bandwidth. An Administrator can improve the user experience by creating a policy that optimizes image compression.

Ok so it looks like the HDX monitor engineering team is not happy with the Out-of-the-Box experience settings from the HDX Adaptive Display engineering team 🙂
I think the HDX Monitor engineering team is right, because if we connect through a fast LAN connection the default Medium compression is used and the windows flag background and other images looks like this :

This is not the best experience you can get with LAN conditions.
Why did Citrix choose this default Out-of-the-Box settings? I think because of a combination between the following 3 points :

1: User Experience
2: Server Scalability
3: Bandwidth Scalability

The default settings also improves the performance on the LAN when viewing high resolution photos etc, if you enabled Progressive display  in the past your users might already be used to this compression level.
But we can consider to improve the user experience for LAN scenarios by lowering the Lossy compression level or turning it off. This can be done in 3 ways :

1: Configure a Lossy Compression maximum threshold

The default threshold for Lossy Compression is set to unlimited, so by default Medium compression is always used. We can change the maximum threshold so we can give it a maximum  value in KBps, above that threshold Lossy Compression will be turned off. This looks like this :

As you can see the Lossy Compression will be turned off when the maximum threshold is reached, for example you can set this threshold on 75% of your LAN speed. The side effect of this one, is that you don’t have any Lossy Compression at all when the Bandwidth is above the maximum Threshold. This can be negatively impact your environment with a lot of LAN users viewing high resolution photos.

2: Set the Default Lossy Compression to Low

If we want to improve the user experience on the LAN, we can also lower the Lossy Compression to the lowest level. This looks like this.

Keep in mind that Adaptive Display will try to maintain this starting JPEG Quality also for your WAN users.

3: Configure different Adaptive Display policies and filter them on IP address

This one is a little bit the same as we configured for Progressive Display in the past.
Make a policy which applies a low level of Lossy compression for you LAN users and filter them on internal IP ranges and give it a higher priority then your default policy.
You can let the default policy (which applies to all users) default or change it with higher compression levels. In this scenario we only give the LAN users a higher starting JPEG quality.

Conclusion :

Do we need to fine-tune Adaptive Display?
I think we need to take this into consideration depending on the use case, for example :
– Do your users need to see lossless images on the LAN?
– Is your environment (Network, Servers, Client Devices) fast and scalable enough?
I also think the default Out-of-the-Box configuration is fine for most environments, but as you can see there are possibilities to change the default behavoir of Adaptive Display slightly to fit your needs.
You can do this by changing the compression levels and telling Adaptive Display what’s the starting JPEG Quality and the Minimum acceptable JPEG Quality.

What do you think? Please leave a comment on your thoughts.
Please note that the information in this blog is provided as is without warranty of any kind, it is a mix of own research and information from the following sources :

– Citrix Edocs “Configuring Adaptive Display” (Contains wrong information about the default Lossy compression level values)
– Citrix Blog “Dynamic Color Compression”
– Citrix Blog “Introducing Adaptive Display”

Popup in IE after installing Hotfix XA650W2K8R2X64025 and HDXFlash200WX64001 for XenApp 6.5

/ Bram Wolfs / 4 Comments

** Update **
Please read this blog post for additional information.

I noticed in some environments that after installing XA650W2K8R2X64025 and HDXFlash200WX64001 for XenApp 6.5 (wich fixes a lot of flash redirection issues in XA65) the users are getting an popup in Internet Explorer about the VDAredirector.exe opening outside IE protected mode :

(Screenshot is from a user with the Dutch language pack enabled)

English message :

This program will open outside of Protected mode. Internet Explorer’s Protected mode helps protect your computer. If you do not trust this website, do not open this program.

Name: Citrix FTA, URL VDA Redirector
Publisher: Citrix Systems, INC

Resolution :

After selecting “Do not show me the warning for this program again” and clicking on “Allow” i searched the registry and found the following key :

[HKCU\Software\Microsoft\Internet Explorer\Low Rights\ElevationPolicy\{BFFC40A2-FFE2-4E6F-B179-3641561D4FCD}]
“AppName”=”VDARedirector.exe”
“AppPath”=”C:\\Program Files (x86)\\Citrix\\system32”
“Policy”=dword:00000003

Import this registry key into RES Workspace Manager (loginscript or other environment manager software you are using) apply it to your users and they will not be bothered with this warning message!