Virtualisation, for example, allows more than one user to run a desktop session on a centralised server. Another less discussed but perhaps more important component is connection brokering.

One major side effect of centralising desktop resources is the disembodiment of the PC: The single unit sitting on the desktop is replaced by a small, often solid-state device at the desk that connects back to some sort of computer - whether a blade, a 1U server or a virtual machine - housed in the data centre. What was one became at least two, but usually even a greater number of components.

Connection brokering traces its origins to allowing IT administrators to simplify the management of this centralised, "disembodied" PC. Clearly, policies had to be set determining which client device would connect to what server resource. This relationship management is primarily what the early connection brokers did.

The first generally available connection broker was released in 2003. The software allowed administrators to easily create mappings between edge devices and back-end host hardware. When users logged on to their client devices, they would find themselves magically attached to the right data centre resource.

The designers of this early-stage brokering software found the new disembodied paradigm created some exciting opportunities. Because the connection to the CPU and storage occurred via IP, in the event of a failure, the broker could play the part of a failover manager, sending the user to a properly functioning resource rather than the initially allocated but now malfunctioning server or blade.

The architecture, in fact, is the equivalent of having a massive virtual KVM switch at your disposal, making it possible to switch from one session to another. This allows developers, quality-assurance engineers, financial-services traders and other power users to gain access instantly to almost unlimited compute power, all from a single, small desktop device.

As the notion of centralised PCs began to heat up, a healthy ecosystem of companies developing software for the market came about. In the interim, virtualisation matured substantially and was rapidly entering the desktop arena, having proven itself in the server virtualisation and quality-assurance facilitation segments.

Because virtual machines increasingly were being used as desktops running on data-centre hardware, the need became paramount for software that could keep track of the myriad possible connections between virtual machines and thin clients. Thus, connection brokers became linked inextricably to the success of virtual machines as virtual desktops.

To address the need, Citrix Systems, the long-time developer of thin-client and remote access software, announced its Virtual Desktop Infrastructure initiative as a solution that would integrate its thin-client software with virtualisation and connection brokering. And VMware, the virtualisation behemoth, announced it was acquiring a connection broker vendor.

The current state of the art in connection-brokering technology eases the integration of virtualiation technologies for desktop. As the centralised model is assimilated, additional areas where connection brokers can add value become increasingly obvious. The technology, for example, makes it possible for remote troubleshooters to take over a user session or simply mirror it to help users resolve problems.

If centralised computing becomes the dominant paradigm for PCs in the coming years, as some predict, connection brokers are positioned to become the new resource managers: higher-level operating systems that take on responsibilities for which traditional PC operating systems were not designed.

Future connection brokers will factor in network conditions and geography to determine how connections will be made. Some of them already intelligently allocate least-loaded resources to users, thus managing all centralised PCs as a "single" resource. These capabilities will become more advanced.

Mobile devices, for example, will be supported by future connection brokers as simply another form of client, which maps neatly to visions where storage and compute power exists in unlimited quantities in the cloud, supporting any duly authenticated access device.

Connection brokers then, are poised to be the gatekeepers and decision makers in this environment, operating seamlessly in the background, always connecting the right user to the right resource at the right time.

Amir Husain is CTO of ClearCube Technology. He may be reached at [email protected]