Connecting users to their virtual desktops is only one part of an overall VDI deployment, but the connection broker can make or break the end-user experience.
Initially, most administrators use the connection brokers that are included with their virtual desktop infrastructure (VDI) products. Citrix shops start out with the broker bundled with XenDesktop, while VMware users typically use the View connection broker. But you may eventually want to move to a more robust, third-party broker simply because proprietary connection brokers often lack the capabilities necessary for heterogeneous environments.
Delivering high-definition desktops
Many desktop virtualization vendors promote a high-definition experience in which video, keystrokes, screen updates and access to peripherals are provided without delay, degradation or other interference. Delivering an HD experience has become so critical to VDI that some vendors have created groups of technologies dedicated to delivering HD, such as Citrix HDX.
But the HD experience starts with the connection broker, which acts as part traffic cop and part telephone operator. It handles the authentication and connection between endpoints (clients) and virtual machines (VM) and directs remote requests to the proper VM or service. It also simplifies reconnections if the link from the client to the VM is broken.
Some connection brokers are proprietary to vendor products. For example, VMware and Citrix have their own proprietary display protocols -- PC over IP and HDX, respectively -- and both have their own integrated connection brokers. But connection brokers are one of the few vendor-agnostic elements of a VDI deployment, so you can be picky about which product you choose, and you can swap it out for something else if a particular connection broker does not meet your needs.
Here is a breakdown of some vendor-agnostic connection brokers that support an HD experience.
Ericom's PowerTerm family of "enhanced" connection brokers not only connects users to virtual desktops but can also serve as tools for management and provisioning. The products support a number of virtualization platforms, including VMware, Microsoft and Citrix, as well as Windows Terminal Services (Remote Desktop Services).
Each of Ericom's three connection-broker offerings incorporates different features for specific use cases. For example, PowerTerm WebConnect RemoteView offers the basics for connectivity to virtual machines and applications and is aimed at replacing legacy Citrix systems with VDI.
PowerTerm WebConnect DeskView lets IT pros provision, deploy and centrally manage Windows-based virtual desktops hosted on various virtualization platforms. PowerTerm WebConnect Enterprise is a more comprehensive product for server-hosted computing products such as Terminal Services, VDI, traditional Citrix offerings and Remote Desktop Protocol, so it's a good choice for those moving from legacy Terminal Services deployments to VDI.
Ericom's connection brokers contribute to a high-definition experience by applying compression and acceleration technologies to the display protocols used by many virtualization vendors. What's more, the product handles disconnects and reconnects seamlessly.
Leostream's approach is different because it packages its connection broker as a virtual appliance that runs on a virtual host. It functions like the proprietary connection brokers that vendors bundle with their VDI products, but it is vendor-agnostic, so it can be used in heterogeneous data centers.
The Leostream Connection Broker establishes access-control rules that connect end users to the right resources at the right time, regardless of their location. It also manages the connection of end users to their desktops and applications without sitting in the data path.
The product connects users directly to physical and virtualized desktops, terminal server sessions, and applications according to the user's profile and the location of the client device. Leostream's broker also integrates with an organization's directory services, such as Microsoft Active Directory and Novell eDirectory, to authenticate users and map them to one of the access-control rules. That integration makes it simpler to manage users, policies and endpoints, reducing management overhead and speeding VDI deployments.
Leostream's product also supports a high-definition experience by working outside of the VDI data path, so it doesn't affect throughput or introduce latency into the VDI connection. In addition, Leostream Connection Broker incorporates intelligent policy controls, which can be used to associate specific sessions with particular endpoints, creating VMs that are matched to particular user experiences.
Quest vWorkspace is another vendor-agnostic connection broker that provides connectivity and authentication for VDI clients, terminal server endpoints and blade PCs. It also provides management capabilities, including authentication policies, enhanced security and user administration controls for VDI.
In addition, Quest vWorkspace uses algorithms to optimize performance, reduce latency and improve display protocols.
These three products represent a small sampling of connection broker offerings on the market today. Like these products, other third-party connection brokers offer more than just connectivity services. They also incorporate features that can improve the end-user experience such as compression, latency reduction and high-definition capabilities.
ABOUT THE AUTHOR:
Frank Ohlhorst is an IT journalist who has also served as a network administrator and applications programmer before forming his own computer consulting firm.
This was first published in March 2011