Delivering Softphones with Citrix XenDesktop 5.5 / 5.6

Written by Thomas Poppelgaard. Posted in Citrix, HDX, XenDesktop

Citrix have released this great article on how to deliver Softphones with Citrix XenDesktop 5.5 / 5.6

Summary

This article describes a generic approach to delivering softphones and voice chat applications with XenDesktop 5.5 and 5.6.

Alternatives for delivering softphones

XenDesktop supports several alternatives for delivering softphones:

  • Control mode, where the hosted softphone simply controls a physical telephone set
  • Generic softphone support (VoIP-over-ICA)
  • Optimized softphone support (media engine runs on user device, and VoIP traffic flows peer-to-peer)

This article focuses on generic softphone support, where an unmodified softphone is hosted on XenDesktop in the data center and the audio traffic goes over Citrix ICA protocol (UDP or TCP) to the user device running the Citrix Receiver. Generic softphone support is a feature of HDX RealTime.

Generic softphone support

There are two aspects to softphone delivery using XenDesktop:

  • How the softphone application is delivered to the virtual desktop
  • How the audio is delivered to and from the user’s headset, microphone and speakers, or USB telephone set

XenDesktop 5.5 and the Citrix Receiver 3.0 for Windows introduced several valuable enhancements to generic softphone delivery:

  • Low latency audio path
  • Client-side jitter buffer – Ensures smooth audio even when network latency fluctuates
  • Audio plug-n-play – Audio devices do not need to be plugged in before starting a XenDesktop session, they can be plugged in at any time during a session
  • Improved echo cancellation – Allows for greater variation in the distance between microphone and speakers for workers who do not use a headset
  • Audio device routing – Users can direct ringtone to speakers but the voice path to their headset
  • Multi-stream ICA including UDP/RTP – Enables flexible Quality of Service (QoS)-based routing over the network
  • Packet tagging (DSCP and WMM) for QoS
    DSCP tagging for RTP packets (Layer 3)
    WMM tagging for WiFi

How the softphone application is delivered to the virtual desktop

There are two methods by which a softphone can be delivered to the XenDesktop virtual desktop:

  • It can, of course, be installed in the virtual desktop image.
  • Alternatively, as a best practice, it can be streamed to the virtual desktop using On-Demand Applications by XenApp, a feature of XenDesktop Enterprise Platinum Edition. This second approach has manageability advantages because the virtual desktop image is kept uncluttered. Once streamed to the virtual desktop, the application executes in that environment just as if it had been installed in the traditional manner.

How the audio is delivered to and from the User Device

XenDesktop supports two methods of delivering audio to and from the user device: Generic USB redirection (for LAN-connected users only) and the Citrix Audio Virtual Channel.

  • Isochronous USB Redirection
    Citrix’s Generic USB Redirection technology (CTXGUSB virtual channel) provides a generic means of remoting USB devices, including isochronous USB devices such as headsets and webcams. This approach is generally limited to LAN-connected users because the USB protocol tends to be sensitive to network latency and requires considerable network bandwidth. Isochronous USB redirection has been found to work very well with some softphones, providing excellent voice quality and low latency, but it is generally preferred to use the Citrix Audio Virtual Channel which is optimized for audio traffic. An exception is when using a USB telephone attached to a user device that is LAN-connected to the data center; in this case, Generic USB Redirection offers the advantage of supporting buttons on the phone set that control features by sending a signal back to the softphone.
  • Citrix Audio Virtual Channel
    The Citrix Audio Virtual Channel (CTXCAM) and the Bidirectional Audio feature of XenDesktop enable audio to be delivered very efficiently. XenDesktop takes the audio from the user’s headset/microphone, compresses it, and sends it over ICA to the softphone application on the virtual desktop using the audio virtual channel. Likewise, the softphone’s audio output is compressed and sent in the other direction to the user’s headset or speakers. This compression is independent of the compression used by the softphone itself (such as G.729 or G.711). It is done using the Optimized-for-Speech codec. This is, in fact, the Speex codec (see http://www.speex.org/), and its characteristics are ideal for voice-over-IP (VoIP).

Citrix generally recommends using Bidirectional Audio (leveraging the XenDesktop audio driver) rather than raw isochronous USB redirection because this consumes less bandwidth and puts less of a load on the server. However, if using a USB telephone on the LAN, then Generic USB Redirection (CTXGUSB virtual channel) is recommended because both signaling and audio are involved.

To use either isochronous USB redirection or the optimized-for-speech audio codec, the user device must be equipped with either the Citrix on-line plug-in for Windows version 11.2 or later, or the Citrix Receiver for Linux version 11.100 or later. It is recommended to use the latest versions of the Citrix Receiver to get the benefit of ongoing HDX enhancements. For example, significant improvements to audio quality were introduced in the Citrix Receiver 3.0 for Windows (13.0 online plug-in) and the Citrix Receiver 12.0 for Linux.

System Configuration Recommendations

Client hardware and software

For optimal audio quality, Citrix recommends the Citrix Receiver 3.x for Windows and a good quality headset with echo cancellation.

The 12.0 online plug-in for Windows introduced echo cancellation into the client software, allowing the use of speakers and a microphone as an alternative to using a headset. This has been further enhanced in the Citrix Receiver 3.0 with version 13.0 of the online plug-in.

On each user device, install the latest Citrix Receiver for Windows or Linux. These versions include the Optimized-for-Speech audio codec technology required for softphone use.

CPU considerations

Monitor CPU utilization on the VDA to determine if it is necessary to assign two virtual CPUs to each virtual machine. Real-time voice and video are data intensive and configuring two virtual CPUs reduces the thread switching latency. Note that having two virtual CPUs does not necessarily mean doubling the number of physical CPUs, because physical CPUs can be shared across sessions.

Citrix Gateway Protocol (CGP), which is used for the Session Reliability feature, also increases CPU consumption. Improvements in XenDesktop 5.5 have greatly reduced the CPU impact of Session Reliability / Citrix Gateway Protocol (CGP). Nevertheless, on high quality network connections this feature could be disabled to further reduce CPU consumption on the VDA.

Neither of the above steps might be necessary on a powerful server.

Settings for use on WAN connections

Voice chat can be used over both LAN and WAN connections. On a WAN connection, audio quality depends on the latency, packet loss, and jitter on the connection. If delivering softphones to users on a Wide Area Network (WAN) connection, the following additional configuration settings are recommended:

  • Use XenDesktop 5.5 or above for best results.
  • Use Citrix Repeater and Branch Repeater between the data center and the remote office for Quality-of-Service (QoS). The Citrix Branch Repeater supports Multi-Stream ICA, including UDP. Also, in the case of a single TCP stream, it able to distinguish the priorities of the various ICA virtual channels to ensure that high priority real-time Audio data gets preferential treatment.

Use the HDX Monitor to validate your HDX configuration.

Audio service priority

If you are running XenDesktop 5.5 or above, there should be no need to adjust the priority of the Audio service. On earlier versions of XenDesktop, however, check the priority of the Citrix Audio Service (CtxAudioService) on the Virtual Desktop Agent. If it is set to Normal, increase the priority to Above Normal. (See Microsoft article; this topic is also discussed in CTX124516 - How to Optimize HDX MediaStream Server-Rendered Video).

Audio virtual channel priority

If you are running XenDesktop 5.5 or later, there should be no need to adjust the priority of the Audio virtual channel. On earlier version of XenDesktop, Citrix recommends setting the priority of the Audio virtual channel (Client Audio Mapping) to 0 (real-time priority).

If using XenDesktop 5.0, see CTX128190 - How to Change Virtual Channel Priority in XenDesktop 5. To do this on XenDesktop 4 and earlier, see CTX118836 - How to Optimize Audio for XenDesktop.

Note: If the clients are not configured to use the Optimized-for-Speech audio codec, then this setting is not recommended on WAN connections.

UDP audio

Audio over UDP provides excellent tolerance of network congestion and packet loss, and is preferred over TCP when available. XenDesktop 5.5 offers an Audio over UDP Real-time Transport user policy setting.

UDP audio requires XenDesktop 5.5 or later, and the Citrix Receiver 3.x for Windows, which includes the 13.0 online plug-in. The feature can only be used with medium quality audio (Optimized-for-Speech).

To enable UDP Audio, refer to the following links:

http://support.citrix.com/proddocs/topic/xendesktop-als/hd-audio-settings-ad.html

http://blogs.citrix.com/2011/09/07/introducing-udp-transport-in-hdx

Codec Selection and Bandwidth Consumption

Between the user device and the XenDesktop VDA platform in the data center, Citrix recommends using XenDesktop’s Optimized-for-Speech codec setting, also known as Medium Quality audio. Choosing the Medium quality setting, rather than the default High Definition setting, minimizes bandwidth consumption and latency (encoding time). The Medium quality codec is specially optimized for voice-over-IP. It consumes approximately 56 kilobits per second of network bandwidth (28 kilobits per second in each direction), peak.

Between the VDA platform and the IP-PBX, the softphone uses whatever codec is configured or negotiated:

• G711 provides best voice quality but has the highest bandwidth requirement of 80 to 100 kilobits per second per call (depending on Network Layer2 overheads).

• G729 provides good voice quality and has the lower bandwidth requirement of 30 to 40 kilobits per second per call (depending on Network Layer 2 overheads).

More information

CTX118216 - Microsoft Office Communications Server 2007 Application Delivery Best Practices

CTX124655 - Best Practice: How to Configure XenApp 6 Voice and Video Chat Features for Microsoft Office Communicator 2007 R2

CTX130912 - Testing and Using Audio and Video on Microsoft Lync 2010 with XenDesktop 5.5 or 5.6

CTX124634 - XenDesktop Support for Avaya Softphones

CTX124438 - Delivering Cisco IP Communicator from Citrix XenDesktop

CTX111309 - Voice over IP Support with the Citrix Access Gateway Standard Edition

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Beta Hotfix Rollup Pack 1 for Citrix XenApp 6.5

Written by Thomas Poppelgaard. Posted in HDX, Lync, XenApp

Citrix have released a beta version of the upcoming Hotfix Rollup Pack 1 for Citrix XenApp 6.5

When hotfix Rollup Pack 1 is out, it will dramatically improve XenApp 6.5 and still be the leader in SBC.

Features and Enhancements in Hotfix Rollup Pack 1 for XenApp 6.5

Support for Additional Communications Software

In addition to Microsoft Office Communicator and Lync, XenApp now supports the use of Web cams in conjunction with the following communication software published on XenApp 6.5 servers:

  • Citrix GoToMeeting with HD Faces
  • Skypeo
  • Adobe Connect

Enhanced Audio Virtual Channels

Enhancements have been made to the audio virtual channels to help reduce latency. This results in improved performance of softphones and the voice chat feature of Unified Communications applications.

Adaptive Display Settings for Smooth-running Videos and Slide Shows

Adaptive Display dynamically adjusts image quality and frame rates to deliver the best possible user experience when viewing graphics or server-rendered video content over a limited bandwidth network connection. Adaptive Display is the successor to Citrix’s highly successful Progressive Display technology. Adaptive Display is self-tuning and generally does not require configuration.

Windows Media Redirection Enhanced Flow

ControlEnhancements to Windows Media Enhanced Flow Control provide improved results for streamed HD videos delivered over WAN connections.

XenApp 6.5 Mobility Pack

This feature improves the experience of Citrix Receiver users working in supported Windows applications and published server desktops on mobile devices.

Universal Print Server Support

Citrix Universal Print Server extends XenApp 6.5 Universal printing support to network printing. This feature eliminates the need to install numerous network printer drivers on XenApp hosts, and enables more efficient network utilization. The new Citrix Universal printer driver supports direct network printing on Windows and non-Windows clients.

Internet Explorer 9 Support

Internet Explorer 9 has been validated for XenApp 6.5. Citrix is committed to ensuring the best possible compatibility with the latest Microsoft products and provides best effort support for Internet Explorer 9 in XenApp 6.5.

Source

The beta version is not available to the public yet. If its important you get access to this release then please contact Citrix.
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Citrix Cloud Provider Pack for Citrix XenApp 6.5

Written by Thomas Poppelgaard. Posted in App Orchestration, Citrix, Local App, Mobility Pack, XenApp

About Citrix Cloud Provider Pack

This powerful collection of enabling technologies, available exclusively to certified Citrix Service Providers (CSPs), makes it easy to set up “Windows-as-a-Service” hosting businesses that are simpler to run, less costly and better optimized for mobile devices.

App Orchestration Technology This groundbreaking new capability automates the design, configuration, deployment and lifecycle maintenance of Windows apps and desktops hosted by CSPs for multiple tenants, across multiple farms. App orchestration is a requirement in order to attain cloud-scale and cloud-economics. From a single interface, cloud provider admins can define a workspace, performance characteristics, network configuration, and isolation requirements, and have the orchestration engine complete the deployment – hands-free. When it comes time to update apps or desktop images, the admin simply points to the new image, and the app orchestration engine handles draining servers and migrating subscribers without manual intervention. In addition, a new update to Citrix CloudPortal Services Manager provides out-of-the-box support for App Orchestration, enabling the hosted desktop infrastructure to autonomically respond to account provisioning requests via CloudPortal. For additional information regarding this technology please visit Citrix eDocs. Please be sure to review the Quick Deployment Guide.

Seamless App Technology For decades, Citrix has led the industry in “seamless apps” – making an application that’s running in a remote datacenter integrate with a local desktop environment – where we make it practically impossible for an end user to tell whether an app is running locally on their device or virtually in the datacenter. The Cloud Provider Pack moves this technology forward for the future with new capabilities designed specifically for the cloud. With this latest technology, end users can now have their personal, local apps alongside private-cloud business apps from their employer, all seamlessly presented in a cloud-based desktop with standard productivity suites. This unique ability to stitch together personal, private and public cloud components is unprecedented and not only improves the end user experience, but also simplifies customer on-boarding for cloud providers. It is no longer necessary to migrate every app in the entire customer desktop environment to the cloud prior to rolling out cloud desktops; providers can move the easy ones first, transition more difficult ones later, and even leave some apps local as deemed appropriate by the business owner. Please be sure to review the Local App Access Readme and Local App Access guide.

Mobility Pack With millions of mobile devices and millions more Windows apps and desktops in use, everyone is looking for a way to bridge the gap – and have the experience be intuitive and friendly. While there are many ways to view a Windows desktop from a tablet device, making the experience usable and touch-optimized is another matter altogether.  The Mobility Pack for XenApp 6.5 accomplishes this by transforming the standard Windows PC experience into a more touch-friendly interface, with larger icons, iOS and Android-native menus and options, and auto pop-up keyboard for text entry. There are dozens of clever enhancements in the Mobility Pack, as well as a complete SDK for customizing specific apps for mobility.  These customizations can even extend to allowing hosted apps to interact seamlessly with mobile device features such as GPS, Camera, or SMS. (The Mobility Pack was first introduced in December 2011; the Cloud Provider Pack includes important updates.)

Source

Download Citrix Cloud Provider Pack for Citrix XenApp 6.5 here

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Citrix Receiver 11.5 for Mac

Written by Thomas Poppelgaard. Posted in Apple, Citrix, Receiver, VDI-in-a-box, XenApp, XenDesktop

About Receiver for Mac

Citrix Receiver for Mac provides users with self-service access to resources published on XenApp or XenDesktop servers. Receiver combines ease of deployment and use, and offers quick, secure access to hosted applications and desktops.

Citrix Receiver for Mac has been enhanced for on-demand access to Windows, Web, and Software as a Service (SaaS) applications. You can use it for web access or configure it for use with Citrix CloudGateway.

What’s New

Citrix Receiver for Mac 11.5 provides the following new features and enhancements for customers:

  • CloudGateway Express Interoperability. Enables existing XenApp and XenDesktop customers to deliver all their Windows apps and desktops to any device using a unified StoreFront with self-service.
  • CloudGateway Enterprise Interoperability. Enables enterprises to aggregate, control, and deliver all of their Windows, web and software-as-a-service (SaaS) applications to any user on any device.
  • Pass-through authentication to AppController. When used with Receiver Storefront 1.1, once logged on to Citrix Receiver, users can access Web and SaaS applications through AppController without needing to authenticate again. No Receiver-specific administration is needed to use pass-through authentication support.
  • Flexible installation methods. You can install Receiver for Mac from Receiver for Web and Web Interface or you can use Electronic Software Distribution (ESD) tools like Casper Suite.
  • Self-service. Citrix Receiver displays all the resources that you make available to users. Users can browse the list or search for the resources they require and subscribe with a single click. Enabled using one-click configuration and CloudGateway.
  • One-click configuration. Opening a service record after installing Citrix Receiver activates self-service access to CloudGateway-published resources. You can publish a service record on a web site or email it to multiple users.
  • Auto-provisioned applications. Receiver automatically adds administrator-designated applications when users first authenticate. Requires CloudGateway StoreFront.
  • Receiver for all devices. User experience is consistent across Receiver platforms and devices.
  • Follow-me subscriptions. Users’ selected applications follow them across devices. Requires CloudGateway StoreFront.
  • Workspace control. Provides users with the ability to roam. They can disconnect quickly from all running applications and desktops and reconnect to them. Workspace control enables users to move between user devices and gain access to all of their desktops or open applications when they log on.

Source

Download Citrix Receiver 11.5 for Mac here

Read all issues that have been fixed in this release here

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Citrix Receiver 3.2 for Windows

Written by Thomas Poppelgaard. Posted in Citrix, Receiver, VDI-in-a-box, XenApp, XenDesktop

What’s New in this Release

When used with Citrix Storefront 1.1, this release of Receiver for Windows (standard, CitrixReceiver.exe) supports single authentication to Receiver and the browser for Web and SaaS apps published through AppController 1.1. Receiver users will now authenticate with those apps as they have for published Windows apps. No Receiver-specific administration is needed to use the additional single authentication support.

The Receiver Enterprise package did not change for this release. It is required only to support applications that use Smart Card authentication.

Source

Download Citrix Receiver 3.2 for Windows here

Read full overview what has been fixed

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