As organizations look for ways to reduce the cost of installing, updating, managing and making secure desktop and laptop systems, they come across the idea of viewing the laptop or desktop as just an endpoint or access point device. Once they've gotten to this point, they start thinking about all of the ways applications can be "projected" to that device.
The Kusnetzky Group model of virtualization technology (see Sorting out the different layers of virtualization) describes this type of technology "access virtualization." This technology may be used to project access to an application running on a local blade PC, a remote blade server or a general purpose server. To complicate the picture a bit, the application may actually be encapsulated within a virtual machine that is run a local or remote system as well. What some don't consider at all is what protocol is going to be used to support this projected application and that can make all the difference in the usability of some applications.
What protocols are in use today?
Here are some of the protocols that are found in use today:
- Citrix Independent Communications Protocol (ICA) -- this protocol is available on many types of devices from handhelds, thin clients, and as client software for many different types of systems.
- Microsoft Remote Display Protocol (RDP) -- this protocol is available on Windows Mobile-based devices, some thin clients and is part of Windows client operating environments from Windows 95 on (if I'm not mistaken).
- Qumranet SPICE -- this protocol is a recent addition to the list. Qumranet recently was acquired by Red Hat.
- Sun Appliance Link Protocol (also used by VMware -- this protocol is support by Sun's own Sun Ray devices. VMware has teamed up with Sun to use this protocol with their VDI products.
- Teradici -- this protocol requires special purpose hardware, but offers very high performance.
How can an organization choose?
Each of the above protocols offer strengths and have weaknesses. Some of the questions that should be put to the representatives of these companies when they're trying to sell an access virtualization solution, thin client hardware or PC blade solution are:
- Each user needs multiple displays. Does your protocol make them perform well?
- Each user needs the ability to download and upload files. Does your protocol support that?
- Some users need to display high-performance graphics, videos or listen to audio files. Does your protocol support that?
- Mobile staff members may need to access the organization's applications from a system at a customer site, a hotel kiosk or from an internet cafe. How does your approach deal with the security issues this can cause?
- Mobile staff members may want to access applications from a handheld smartphone. Do you offer client software that implements your protocol for my favorite device? (Suspects would include Apple's iPhone, Microsoft Windows Mobile-based devices, Palm's Treos, RIM's Blackberries, Symbian-based devices and, a recent arrival Google Android-based devices).
- We’re seeing increased interest in the importance of display protocols in virtualization solutions – several of the virtualization players have touted the display protocols which their products use (Citrix’s ICA, VMWare & Teradici, VMWare and Sun’s Appliance Link Protocol).
I would urge you to consider protocols when considering an access virtualization solution.
What other questions should you ask your sales rep?