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The Art and Science of Remote Display Protocols

Recently Miercom published a report that was commissioned and paid for by Citrix. VMware did not participate in these tests they, and we have no knowledge around how Miercom/Citrix set those tests up, how they configured VMware View 4, or how they arrived at some of their conclusions.

All that being said, we would gladly welcome the opportunity to take part in unbiased, apples to apples comparison with Citrix as we're confident that VMware View can stand on its own.

As we’ve previously announced, VMware has sold more than 1M VDI seats and leads the virtual desktop market. View 4 has experienced strong uptake since its release in Q4 2009 and customers are reporting excellent results with their desktop virtualization implementations and  PCoIP – they like the superior user experience that comes with the industry’s only protocol that features dynamic bandwidth allocation, the ability to have a superior experience across rich media as well as standard office applications, and enjoying this experience in both LAN and WAN environments. Our customers are our best references – and we’d be happy to connect you with them so you can hear from them first hand.

With all that being said, I'd like to comment on some of the specific points made in the Miercom report:

In a comparison of Virtual Desktop Infrastructure (VDI) implementations, Citrix XenDesktop 4 provided better overall performance when compared to VMware View 4

It appears that the Miercom report did not consider the image quality of office applications.  XenDesktop 4 uses lossy client side image caching compared to VMware View 4’s lossless techniques, which favor the View 4 user experience.

Many customers insist on lossless image delivery – image compression artifacts are totally unacceptable to them.  The PCoIP protocol provides network efficient progressive image refinement that builds the desktop image to a lossless image.  As a result, View is consistently chosen to deliver a high-quality desktop experience.

XenDesktop 4 used 64% less bandwidth than View 4 with PCoIP for typical tasks

In our testing utilizing the Sysmark benchmark View 4 used 40% less bandwidth when run on a 1Mbps network compared to running the same test on a 100Mbs network.  However, XenDesktop 4 used essentially the same bandwidth in both cases – pointing out the weakness of a fixed quality system – Citrix cannot take advantage of additional network resources when available.  Miercom used 100Mbps as their ‘WAN’ for the single user test which skews the results and is not a real deployment scenario.

To reiterate – the PCoIP protocol dynamically adapts the image quality based on the available network resources – thusly View 4 favors the best user experience when operating on an unconstrained network.  So using a single user session to measure bandwidth performance is not a valid testing scenario.  A more realistic scenario would be to compare View 4 to XenDesktop 4 on a constrained network supporting multiple users – this would result in significantly less bandwidth used by each View 4 session, while giving the best experience possible for the concurrent users.

On the other hand, Citrix HDX uses a fixed quality (set by IT) that cannot adapt to available network resources (even if more bandwidth becomes available) and does not allow them to efficiently use/share the total bandwidth therefore not giving the best user experience. 

Dynamic adjustments in display compression quality result in the best and most consistent user experience for a given network environment.  The PCoIP protocol will fairly share the bandwidth across the active users for a given network segment. 

Flash video was delivered with an average of 65% less CPU usage, 89% less bandwidth, and excellent Quality of Experience by XenDesktop 4 compared to View 4

Part of the strength of PCoIP is the fact that it adapts to the network. So, if you were to test a single desktop, as an example running multimedia, then you would observe that PCoIP consumed whatever bandwidth was available at the time.  If bandwidth is available, it will use it to deliver the highest quality experience.  If bandwidth is restricted, as is recommended in constrained environments, PCoIP "throttles down" to consume less bandwidth and is a “good citizen” in the network.  Our customers report that PCoIP has been game changing for them and enables the delivery of a desktop environment that is secure, scalable, and easy to manage.

For environments where bandwidth is a concern, PCoIP can be configured to limit the amount of bandwidth it consumes. Customers have found they can limit bandwidth and still have a strong user experience.

With regards to the flash video test, this is not an apples to apples comparison – since the tests were conducted running Flash redirection with an unrealistically high packet loss of 0.5 to 5%. 

A correctly provisioned network will have packet loss of 0.1% or less which would result in great video performance.

A 100Mbps “WAN” link is an unconstrained network environment (again, single user test on an unconstrained network is not a "real world" test).

Finally, the PCoIP protocol has no reliance whatsoever on client side driver compatibility, however that is not the case for Citrix’s Flash redirection (in addition to mandating a locally installed Flash client, the Citrix solution also requires more powerful client hardware and increases the operational cost of the client).  Because the Citrix solution only works with Adobe Flash they chose to ignore various other video cases – such as Microsoft Silverlight, Google’s On2 etc. With the PCoIP protocol, current or future versions of Flash, QuickTime or other CODECs/plug-ins will just work.

Overall, XenDesktop 4 uses system resources more efficiently and is capable of scaling more effectively

Enterprises have an investment in their networks and by not dynamically adjusting the user bandwidth to take advantage of the available network resources real dollars are wasted and the user experience is impacted.

Depending on multi-media redirection (MMR) solely does not provide real scalability.  It does not handle the case of common office applications and requires constant investment (by Citrix and the resulting increased IT management) which translates to real cost to IT.  It also does not cover other video options like Apple Quicktime, Microsoft Siliverlight, and Google’s On2 (expected to replace Adobe flash on Google websites including Youtube).

Interesting that Miercom/Citrix does not call out the management costs of HDX Flash optimization/redirection.  In addition to requiring a more powerful (and costly) client, the client media CODECs must be constantly updated as Adobe, Microsoft etc update their media protocols. 

Only VMware View 4 supports a true zero client on the desktop to provide the lowest operation cost, highest security and future-proof scalability (supports any media or graphics).

In closing, we really do believe that VMware View is the only desktop virtualization product that has been designed from the ground up to deliver and manage virtualized desktop environments as a service. And, we do that with less cost and complexity than any other solution on the market.

4 thoughts on “The Art and Science of Remote Display Protocols

  1. VastSlug

    “we do that with less cost and complexity than any other solution on the market.”
    you think?
    We ended up choosing a solution other than yourselves (and Citrix to be fair) due to your high costs.
    I’m from the HE sector in the UK and VMware UK have been poor – especially with any decision to offer campus deals. At least Citrix have made a noble effort in this space (though still not suited to the UK). I can think of at least 14 (of the top of my head) HE institutions that have gone elsewhere as a result of this. I know of 1 who dropped View mid-roll-out and I’m willing to bet there are others out there.
    Not just HE though – several of my peers in other industries share many of my concerns with View.
    Also. View is hardly deigned from the ground up (or the only solution to be designed form the ground up)! it’s a formation of existing technology kludged together to offer an “OK” virtual desktop infrastructure.
    I’m a lover of ESX, etc but View needs to be stopped and actually “designed from the ground up” this time.
    Please don’t be the next Novell and do something about this FUD sooner rather than later. After all you will push your competitors to improve. – They don’t really think of you as a competitor more like a marketing nuisance.
    Hopefully this will make it post!

  2. apu

    I have tested view 4 vs Xen Desktop 4 and the results talks by it selfs.
    We have 30 users plus 25 VoIP extensions working over a 440kbps MPLS link with 120ms of latency.
    The users are “knowledge users” (Office, web, PDF and other office apps). After testing with 3 HP thin clients with teradici chip concurrently the bandwidth was over and the QoE … well I don’t have to depict that. Print… I took my lunch time and back (arround 20 min)to see that a PPT of 35 slides was at the midle of the process (7 MB).
    XenDesktop 4 gave me better results, after the 27 client I could see a little latency problem (cached with speedscreen) when i tried to print the same 7 MB PPT file, the good new is that I could get the print after 5 minutes.
    Conclusion, ICA protocol beats PC over IP and is the cheaper option if you pretend to deploy Virtual Desktops. You can choose between wichever major hypervisor and if you chose HyperV you can get the OS of each guest for free. By the way: Windows 7 is full supported over XD4
    I have a PhD in Computer science and the results are very usefull for an investigation I’am doing. I plans to publish the results in IEEE shortly, but I will put the hard data in this forum when i finish the last draft.

  3. Shure Microphones

    I’m from the HE sector in the UK and VMware UK have been poor – especially with any decision to offer campus deals. At least Citrix have made a noble effort in this space (though still not suited to the UK). I can think of at least 14 (of the top of my head) HE institutions that have gone elsewhere as a result of this. I know of 1 who dropped View mid-roll-out and I’m willing to bet there are others out there.

  4. Adam

    PCoIP is certainly a great display protocol. However in some scenarios of high latency/low bandwidth remote connections (like over certain WANs), you need to complement the VMware View deployment with Ericom Blaze, a software-based RDP acceleration and compression product that provides improved performance over WANs and other slow networks. Besides delivering higher frame rates and reducing screen freezes and choppiness, Blaze accelerates RDP performance by up to 10-25 times, while significantly reducing network bandwidth consumption especially over low-bandwidth/high latency connections.
    You can use VMware View with PCoIP for your LAN and fast WAN users, and at the same time use VMware View with Blaze over RDP for your slow WAN users. This combined solution can provide enhanced performance in both types of environments, letting you get the best out of VMware View for your users.
    Read more about Blaze and download a free evaluation at:

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