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HDX versus PC-over-IP: The protocol war is not over yet

Microsoft's Remote Desktop Protocol, VMware's PC-over-IP and Citrix's ICA, renamed HDX, are all good enough, but the struggle for the title of best remote protocol isn't over yet.

At a recent conference, I said, "The remote protocol no longer matters. Both options [Citrix HDX and VMware PC-over-IP] are good enough." While I stand behind that statement -- both protocols are good enough (with caveats of course) -- that doesn't mean that the remote protocol war is over.

For years, there were only two Windows remoting protocols: Microsoft's built-in Remote Desktop Protocol (RDP) and Citrix's add-on Independent Computing Architecture (ICA). Lots of others popped up here and there, some standalone and some that enhanced RDP, but really it was RDP or ICA.

But that all changed when VMware released View 4.0 in November 2009 with a software-only implementation of Teradici's PC-over-IP (PCoIP) remoting protocol. And in that single move, the "ICA or RDP" conversation instantly became a question of "ICA, RDP or PCoIP?" (Actually, Citrix also changed the branding around ICA to HDX, so I guess the conversation now is "HDX, RDP or PCoIP?")

More on the remote protocols

Microsoft Getting started with Remote Desktop Protocol

VMware The inner workings of VMware View 4

Citrix What is Citrix HDX?

So which protocol should you use? We could write about 10,000 words on the topic, but the reality is that today's versions of ICA, RDP and PCoIP are all really good. And that simple fact led to my statement about the remote protocol not mattering. What I meant is that customers choose to buy Citrix XenDesktop, VMware View or some other desktop virtualization product for reasons other than the quality of the remote protocol. That's not to suggest that there aren't situations where one protocol does better than another, but all three protocols are pretty solid.

But if the protocols are good enough, and if customers pick a desktop virtualization product for other reasons, does that mean that the three-way protocol war is over?

Hardly! All three vendors have made major announcements about future improvements to their protocols.

  • Microsoft has announced that Windows 7 Service Pack 1 will include an enhancement to RDP called RemoteFX, which it claims will deliver flawless graphical quality over LAN connections, even when viewing graphically intense applications and multimedia on multiple client displays. Some eagle-eyed bloggers <<a href="" target="_blank"> found a job description for an open position at Microsoft for an engineer who will work on the remote desktop team to take virtual desktop infrastructure (VDI) to the "next level" in Windows 8.
  • Citrix recently announced HDX Nitro, which is the codename for several next-generation HDX capabilities, including faster performance across the board, faster printing with less bandwidth, and better intelligence around how graphics are rendered over different connection speeds.
  • Even though VMware's first product leveraging PCoIP is less than a year old, the company has already released an update that adds built-in driverless printing based on ThinPrint technology it had previously licensed. And while VMware hasn't officially announced View 4.5 yet, it's widely expected that it will enhance the security of PCoIP and tune the performance over WAN connections.

So even though all three protocols are good, it's unlikely that Citrix, Microsoft, or VMware will ever be "done" with them. Isn't competition great?

Brian Madden is an independent industry analyst and blogger, known throughout the world as an opinionated, supertechnical desktop virtualization expert. He has written several books and more than 1,000 articles about desktop and application virtualization. Madden's blog,, receives millions of visitors per year and is a leading source for conversation, debate and discourse about the application and desktop virtualization industry. He is also the creator of BriForum, the premier independent application delivery technical conference.

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