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HDX RealTime Optimization Pack 1.1 for Microsoft Lync

Citrix have released a new version of HDX RealTime Optimization Pack 1.1 for Microsoft Lync

Citrix HDX RealTime Optimization Pack for Microsoft Lync offers clear, crisp high-definition video calls in conjunction with Microsoft Lync. Users can seamlessly participate in audio-video or audio-only calls to and from other HDX RealTime users and other standards-based video desktop and conference room systems.

Citrix HDX RealTime Connector for Microsoft Lync runs in both the Citrix XenDesktop virtual desktop and in the Citrix XenApp virtual application environments

About HDX RealTime Optimization Pack 1.1 for Microsoft Lync

Citrix HDX RealTime Optimization Pack for Microsoft Lync provides a highly scalable solution for delivering real-time audio-video conferencing and USB or VoIP enterprise telephony through Microsoft Lync in XenDesktop and XenApp environments. HDX RealTime Optimization Pack leverages your existing Lync infrastructure and inter-operates with other Lync endpoints running natively on devices.

HDX RealTime Optimization Pack for Microsoft Lync consists of both client and server components:

  • The client component, called Citrix HDX RealTime Media Engine, is integrated with the Citrix Receiver on the endpoint device and performs all signaling and media processing directly on the user device itself, offloading the server for maximum scalability, minimizing network bandwidth consumption and ensuring optimal audio-video quality.
  • The server-side (and virtual desktop) component, Citrix HDX RealTime Connector for Microsoft Lync, is a connector to the Microsoft Lync client that drives the RealTime Media Engine on the endpoint. Connector runs in the virtual server environment alongside Microsoft Lync and communicates signaling information over a Citrix ICA virtual channel to the RealTime Media Engine running on the user device.

What’s New

  • Enterprise Voice telephony features (PBX/PSTN integration)
  • Emergency Services support (E911)
  • Support for buttons (HID functions) on USB phones/headsets
  • Conformance to Microsoft Lync Call Admission Control specification
  • SUSE Linux support (v11 SP1/SP2)
  • Support for Logitech C920 webcam with built-in H.264 encoder
  • TCP/IP fallback for firewall traversal through Edge Server when UDP is blocked
  • Compatibility with XenDesktop Remote PC feature
  • Compatibility with CloudGateway StoreFront 1.2 for automated updating of the HDX RealTime Media Engine plug-in to the Citrix Receiver for Windows


Download Optimization Pack 1.1 for Microsoft Lync here (Require MyCitrix ID)

Beta Hotfix Rollup Pack 1 for Citrix XenApp 6.5

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.


The beta version is not available to the public yet. If its important you get access to this release then please contact Citrix.

Citrix statement on how Microsoft Lync is supported with Citrix XenDesktop

I want to share this informative knowledge article that describes how Microsoft Lync is supported with Citrix XenDesktop.

As stated in Client Virtualization in Microsoft Lync 2010 (, republished by Microsoft in February 2012, delivery of the Lync 2010 client using XenDesktop and XenApp is “Supported” by Microsoft (see Table 2 on page 7). However, audio (voice chat) is not directly supported by Microsoft (see Table 3 on page 8) except through a desk phone using USB Redirection. Likewise, video chat is not directly supported by Microsoft. These statements are based on XenDesktop 4.0 and XenApp 6.0 (see Appendix A.1, page 12). As noted in the footnote on page 13, “XenDesktop 5 (which introduces webcam video compression as an alternative to USB redirection) was not tested.”

How do these statements impact Citrix customers who wish to deliver Microsoft Lync with voice and video chat functionality from XenDesktop 5.5 or XenApp 6.5?

In short, XenDesktop/XenApp delivery of Microsoft Lync, including voice chat and video chat, is fully supported by Citrix.

Microsoft does not directly support third-party products such as XenDesktop. In our experience, customers can expect “best effort” support from Microsoft but in some cases might be asked to duplicate a problem on a regular PC with no Citrix software installed.

Citrix supports the delivery of Microsoft Lync and other similar third-party Unified Communications clients and softphones from XenDesktop (including XenApp) to users of the Citrix Receiver through a variety of innovative technologies including:

  • Optimized-for-speech codec technology, featuring fast encode and low bandwidth utilization
  • Webcam Video Compression in the Citrix Receivers for Windows and Linux, offering excellent bandwidth efficiency and network latency tolerance
  • Jitter buffering in the Citrix Receiver for Windows to ensure smooth audio even when network latency is variable, and Echo Cancellation when users a microphone and speakers instead of a headset
  • Audio plug-n-play
  • Audio device routing (for example: ringtone can be directed to speakers but voice to a headset)
  • Multi-stream ICA transport for full QoS support
  • UDP/RTP audio option on XenDesktop VDI
  • DSCP packet tagging for RTP packets (Layer 3)
  • WMM tagging for Wi-Fi
  • Branch Repeater support for QoS and multi-stream ICA, including UDP

Additional optimizations for Lync 2010 are currently in beta trial, including native support for Microsoft’s proprietary RTAudio and RTVideo codecs without transcoding. Furthermore, Citrix is committed to fully supporting the next release of Microsoft Lync, codenamed “Wave 15”.

More Information

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

CTX128831 – Guidelines for Delivering Microsoft Lync with XenDesktop 5.x

CTX124124 – Configuring XenDesktop 5.5 or 5.6 to Deliver Microsoft Lync 2010

Citrix NetScaler for Lync Server 2010

Citrix NetScaler for Lync Server 2010.

Microsoft® Lync™ ushers in a new connected user experience transforming every communication into an interaction that is more collaborative, engaging, and accessible from anywhere. Citrix® NetScaler® improves the Lync server performance and end user experience through its advanced Application Delivery Controller techniques such as Load Balancing, SSL Bridging & Offload, Advanced Health Monitoring, TCP & SSL Multiplexing, GSLB and High Availability. Deployed in front of the Lync Edge Servers in the DMZ and between the Lync Edge and Front End servers on the internal network, Citrix NetScaler enables a new level of scalability, performance, security, availability and ease of use for Microsoft Lync. At the same time, NetScaler reduces time to deployment, simplifies management and reduces the cost of operations.

Load Balancing

Citrix NetScaler’s advanced Multiplexing software distributes traffic across multiple Lync servers to improve performance and ensure availability. When a
Lync server goes down, Citrix NetScaler routes traffic around it to other servers that are up and running. Citrix NetScaler Load Balancing defaults to the
Least Connections algorithm, but can also be setup to use Round Robin, Least Response Time, Hash Method, Least Bandwidth, Custom Load and Token based algorithms among others.

SSL Bridging & SSL Offloading

SSL bridging enables the NetScaler to bridge all secure traffic directly to the Lync server, without having to import Certificates. When using SSL Briding,
NetScaler does not offload the Certificate processing from the Lync servers, enabling a new level of ease-of-deployment and ease-of-use.

A Citrix® NetScaler® appliance configured for SSL Offloacing accelerates SSL transactions by offloading SSL processing from the Lync servers. Configuring SSL offloading requires an SSL certificate and key pair. Other related SSL capabilities include managing certificates, CRLs, client authentication and SSL

Advanced Health Monitoring

The Citrix NetScaler tracks the state of each Load Balanced Lync server in real-time, so that it can divert traffic from an unresponsive Lync server to a
server that is responding. Lync servers are removed from the list of available servers, until they become responsive again. Citrix NetScaler allows for the
creation of custom monitors specific tor Lync servers.


The Citrix NetScaler provides Global Server Load Balancing for disaster recovery and ensures continuous availability of applications by protecting
against points of failure in a Wide Area Network (WAN). GSLB performs Load Balancing across geographically disparate data centers, by directing traffic to
the closest or best performing data center.

High Availability

Citrix NetScaler High Availability (HA) provides uninterrupted operation for Lync server traffic, by designating a Primary NetScaler and a Secondary
NetScaler. The Secondary NetScaler monitors the Primary, and if the Primary goes down, the Secondary takes over.

Microsoft Lync 2010 Details

To see the ports and protocols used in a Microsoft Lync Server 2010 environment, go here. A poster of the Lync Server 2010 workloads, describing the relationships and traffic flow can be found here. To download and use the Lync Server 2010 Topology Builder tool, go here

NetScaler for Lync Server 2010 Deployment Guide

Citrix have recently spent some time in Redmond, WA with Microsoft’s Lync 2010 team to certify the Citrix NetScaler for deployment with Lync 2010. The deployment guide walks the user through simple steps of configuring the Citrix NetScaler for Lync 2010. Additionally, the user can download the pre-built configuration for Lync Server 2010 used in the deployment guide and upload it to Citrix NetScaler to serve as an example.

Download the Deployment Guide – Citrix NetScaler for Lync Server 2010 here

Download the Citrix NetScaler configuration here.

Delivering Microsoft Lync with XenDesktop 5

Citrix have posted a great knowledge article about delivering Microsoft Lync with XenDesktop 5, i want to share with you. It’s a must read if you are going to implement Microsoft Lync in a Citrix environment.


This article provides guidelines for configuring XenDesktop 5 to deliver Microsoft Lync (formerly Microsoft Office Communicator). Microsoft Lync is a unified communications client used with Microsoft Lync Server that provides instant messaging, voice chat and desktop video conferencing. Citrix XenDesktop with HDX RealTime allows users to communicate using the voice chat and video chat features of Microsoft Lync.

There are three scenarios where HDX RealTime is used with Lync:

  • Voice chat using Voice-over-IP. This feature of Lync is much like using a telephone. It enables users to chat in real time using a headset or USB telephone connected to their computer or thin client.
  • Video conferencing as an observer (voice-only participant). A user may choose to join in a video conference as a voice-only participant. The user can view the video conference and participate in the conversation but does not use a webcam.
  • Video chat using a webcam.

This article describes how to get the best results from both products in these scenarios. It is split into two sections; the first section deals with any configuration changes needed to the XenDesktop 5 environment and the second section looks at Microsoft Lync itself.

For information on using XenApp 6 to deliver Microsoft Office Communicator, see CTX124655 – Best Practice: How to Configure XenApp 6 for Microsoft Office Communicator 2007 R2.

Read the article about delivering Microsoft Lync with XD5 here