In the first part of this two-part article, we discussed the network performance problems that arise when unified communication (UC) applications run across virtual desktop infrastructure (VDI). See what options enterprises have to integrate UC apps into VDI environments in part two.
Real-time challenges for VDI environments
Supporting real-time communications within a virtual desktop infrastructure is challenging. Early attempts to integrate UC software in a virtual desktop environment followed the conventional wisdom of traditional application deployment on desktops -- install the UC software client interfaces on users' virtual machines and rely on the back-end servers to perform the multimedia processing.
Unfortunately, the nature of VDI defies old thinking. This approach created a new set of problems, particularly at scale. For example, VDI relies on the client hardware to intercept the audio and video from the user's endpoint and to transfer it across the network to the server-based virtual machine. This adds a tremendous amount of load to the enterprise network, straining it and exposing voice and video calls to dropped packets or lag.
Early attempts to integrate UC software in a virtual desktop environment followed the conventional wisdom of traditional application deployment on desktops.... Unfortunately, the nature of VDI defies old thinking.
Although enterprises can apply optimization technology to this additional traffic, a server-side deployment of UC apps in a VDI environment is too performance and administrative intensive for all but the smallest of virtual desktop deployments. In fact, the most common method of deploying IP telephony and UC apps in a virtual desktop environment has been to install both a physical telephony endpoint and a thin client device on the user's desk, surrendering much of the operational and administrative benefits of VDI in the process.
However, the need for true UC multimedia collaboration in a VDI environment remains. In response, VDI and UC vendors are developing an alternative to server-side media processing: Client-side media engines. In a client-side model, or split model, the software code of softphones, video clients or UC clients becomes two distinct components -- the user interface and a media engine. This separation recreates the client-server nature of IP telephony and UC, while optimizing the client within the VDI environment.
Supporting a split model for UC apps in a VDI/thin-client environment has several advantages. This approach takes the excessive load off of the server and redistributes the transcoding and multimedia processing back out across the clients. Just like physical endpoints, the client's media engine takes command over calls after the call controller sets up the call. Likewise, network design decisions and configurations around QoS, prioritization and access control remain intact because the media engine-enabled thin client functions on the network like any other endpoint. Network traffic is also optimized because this model eliminates the excessive traffic load from server-based media processing. Finally, because the media engine is a client function, the system maintains calls in process even if the remote VDI server fails.
UC providers, VDI suppliers and thin client developers are embracing the client-side approach with products recently released or currently in development. Some challenges still exist with a client-side approach, notably for enterprises with existing fleets of deployed thin clients. However, retaining the client-server nature of UC in VDI environments is the best approach for using the two technologies together.
Michael’s full report “Streamlining Unified Communications with Virtual Desktop Infrastructure,” which offers greater insight into the challenges and opportunities of integrating real-time UC apps into a VDI environment, is available at http://www.frost.com/q268724256
Dig deeper on VoIP QoS and Performance