Citrix wins virtual desktop interface shootout

Virtual Desktop Interface is becoming easier to do, with potentially killer graphics, reasonable port virtualization, fine-grained administrative control, and with potential hosts other than Windows.

While Citrix XenDesktop/XenApp remains the one to beat, two other VDI platforms we tested, Ericom Connect Enterprise and Parallels Remote Application Server, can provide for the publishing of diverse applications to desktops, while following “the rules” regarding resource accessibility and security.

In testing, we found Citrix leads the pack in terms of overall flexibility, although its vast feature sets can increase support burdens. If price-be-damned and you really want the venerable Full Meal Deal, it’s Citrix XenDesktop/XenApp Enterprise. We found it has almost everything you could ask for in a VDI product.

We found solid extensibility with Ericom Connect, which allows IT managers to create grids of connectivity with no additional licensing costs. This is good for multi-site/multi-tenant organizations.

The easiest entry point was found with Parallels RAS, which is a comparative breeze to install and integrate. It has most of the features found in both of its competitors and a few of its own.

+ A LOOK BACK AT THE 2013 VERSION: Citrix wins VDI faceoff +

The commonality of these three products is that they’re capable of great depth, and in most cases, numerous gradients of feature options. Mostly, their documentation is inadequate, and neophyte admins will need to know something about Remote Access Services before starting.

Part of the problem is the enormous complexity of virtualizing apps plus desktops plus resources and getting everything to run smoothly on a myriad of remote devices, perhaps over a distributed complex network. This is made more difficult by language and international boundaries.

You need to be up to speed with remote access, Active Directory infrastructure, and certificate management. And you need to plan the resources necessary to support the virtualized infrastructure required to do the job.

Securing virtual resources across the open Internet requires more attention to detail, and each VDI package we tested has features that guard against rudimentary host-probing. Certificate infrastructure was most wholesome with Citrix, followed by Ericom Connect, then Parallels RAS.

We tried the full enterprise top-shelf versions of each product, and we caution IT execs that they’ll need to understand the options thoroughly. While each product at its basic will do the basic job, you’ll likely want more, and will need to pay more for the options you want. These options seemed to change over the months that we looked at each product. Enterprise organizations have become used to a somewhat dizzying array of possible options. Here, Parallels RAS and to a lesser extent, Ericom Enterprise Connect have the bliss of simplicity, if with scalability.

Remote roles

Not long ago, it was all you could do to get a remote virtual screen. Microsoft’s RAS and its protocols allowed terminal-like sessions. Then multiple concurrent sessions could be managed, and with the advent of a 64-bit memory map and processor virtualization modes, hypervisor-like virtual sessions and operating system instantiations became possible.

Mobile devices impose new types of OS instantiations, and when publishing apps to mobile devices, session resources can become highly reduced. This reduction in resources, aided by running multiple apps within the same OS instance, then allows publishing apps without dragging a lot of app logic to a remote client/viewer. This also allows app usage on incompatible session devices—like Windows apps on Mac machinery.

Each of the three VDI platforms tested competes with cloud-based apps, made ever-more reliable by Microsoft specifically, as well as others, like Google. Hosted services are a direct competitor, but each of the VDI players has a “secret sauce” that hosted office apps can’t do—yet.

The advent of specialized co-processing boards—GPU arrays that process complex graphics on the host side—enable remote sessions of highly complex graphics apps.

Given decent bandwidth between a session host and a remote client, modernized protocols permit CAD, GIS, and other graphics-intensive apps to be run at considerable distance with only nominal latencies. In the past, latencies made running such programs untenable at best.

The resources for publishing just the app have soared as well. App sources can be anything from traditional Linux and even Mac apps. Sometimes, the app can use added graphics or chipset co-processing, which aids in the remote device perceived response, we found. Other times there didn’t seem to be much of a boost. Much is dependent on the platform, and a session manager’s ability to expose chipset/co-processing resources to the app.

Speed perception can be very important for several reasons, one of which is the nature of support calls and complaints poised when the user doesn’t know if network speed, device speed, or application speed is the crux of finger-drumming complaints. Faster is better.

Speed, along with peripheral integration between a viewing device and client also becomes very important. If there’s a webcam (interactive video or just video viewing), sound indirection, mouse/pointing device movement, or other interactive peripheral device in a session, support for the device(s) becomes very important.

Citrix is the one to beat with device compatibility, but both Parallels and Ericom aren’t far behind.

Parallels supports HTML5, mobile apps, and VDI for PCs, Macs, and to a lesser extent, Linux -- all at a lower competitive cost. But device support is more limited.

Ericom does a similar job (also with limited Linux support), but also allows scale expansion through the use of clustering, and with attachments supports a wide variety of legacy apps.

Here are the individual reviews:

XenApp/XenDesktop Enterprise 7.9

The depth and width of Citrix’s compatible device list, coupled with their virtualize-anything mentality makes them the one to beat in this comparison. There is much organizationally specific customizing and “branding” that can be done, as well. Citrix remains almost hyper-focused on delivering virtualized Windows-based resources to a staggering variety of possible interactive devices.

Before one starts, however, another battle starts that’s become more complex with the varieties of options Citrix offers: licensing, and the implications and gradients of extensibility, which are a function of the Citrix Netscaler line, which we did not review.

The difference between XenApp and XenDesktop is based on the concept of user/device, or concurrent use licenses. You can pick one model, or the other. Citrix goes to great trouble, more than 30 pages to explain the differences and their implications and “stretchyness”.

Architecturally, each organization has to decide which model fits their accessibility needs and budget. There’s a management app to deal with licenses, which might also be tied to other vendor’s licensing, say, Microsoft, SAP, or Oracle using similar “named user” vs. concurrent sessions/users/accesses.

Your legal department may want in on the considerations, along with finance. As both models may involve Microsoft Client Access Licenses (CAL) and application hosting costs, we advise the reader to do the math over the lifecycle of the licenses, hardware, and hosting costs to get a picture of what VDI actually costs. 

We tried XenDesktop on HyperV-3, XenServer 6.5, as well as VMware vSphere 6. There isn’t much difference between installation and use on these varied hosts/hypervisor operating systems. Citrix’s user-device app for remote access is Citrix Receiver, and it supports the same interaction across the five devices we used, including iPhone, Mac, Windows 10, Linux Ubuntu 14.04, and HTML access.

XenDesktop/App integrated well with the Windows 2012R2 Active Directory-based network we used to test, and its connection brokerage via Citrix StoreFront (included and highly customizable) to resources takes place quickly, meaning our sessions were authenticated and proxied to resources we had made, quickly.

The Citrix Receiver, the client side of viewing apps and VDI resources, worked uniformly well across the devices we used to test sessions and apps. The long list of devices supporting a Citrix Receiver is increasing, and the five types we used presented a uniform peripheral support and behavior across Citrix Receiver client devices. We found that if circuit transports have the same base speed, multimedia response is uniform, as well. In other words, we found the Citrix Receiver client behavior has great user experience consistency.

Citrix recommends use of its NetScaler products for widening turf. The atomic unit of administration and focus is the site. A Citrix Site has a delivery controller (running some version of SQL Server), a license server, Citrix Studio and/or Citrix Director (both connection broker/customization links) atop a Windows Server license. Installation of the basics is staggeringly simple, and unlike the other two products compared here, Citrix grabs all of the external bits needed and installs them on the fly, simplifying installation.

We built the site, and used Citrix Studio (included) to create the site, establish the database and logging to work with it, and set the resources that we could build for users. Citrix is glued to Active Directory like Velcro, and we found the resources needed to get our trial apps and desktop configurations developed with little trouble. There are many possible features to virtualize, and we found the process of thinking about the implication of enabling features to be occasionally daunting—usually from a practical support and security perspective. Citrix covers these issues well, and their docs and online help are fruitful.

The possible breadth of virtualized applications can be huge, if sometimes with optional hardware components. We tested the NVIDIA Tesla GPU adapter inside an HPE DL560Gen9 platform. The NVIDIA Tesla serves as a graphics adapter in our use, and permits the heavy lifting of doing combinations of raster/vector graphics inside the host so that virtualized apps under XenDesktop control in the host send almost ridiculously fast rendering.

While we eschew graphics benchmarks, the difference using ESRi (a GIS app) with and without the Tesla support (selectable) hosted then virtualized in the XenDesktop-Receiver circuit through broadband was simply startling to us. A side-by-side comparison of desktop app with, and without GPU support reminded us of the speed difference between an ISDN modem link and GBE.

Citrix was the only member of the group tested that supports this board, which is compatible with other hosts, but must be mated specifically to each hardware platform supported. For the narrow number of use cases that need whoppingly fast graphics, we’ve seen nothing faster, protocol-enhanced or not. The work is done in the host, not otherwise enhanced by a protocol, as has been done elsewhere.

We accessed our virtualized resources, as with others, in this comparison, from devices both in our lab (connected via broadband), but also at random locations like famous chain coffee shops, home offices, and in motels with bad Wi-Fi—the kind where you know everyone’s watching NetFlix instead of paying for TV.

We didn’t experience any session crashes on any device, except for our Samsung S3s, but we also cannot guarantee our telecom providers adherence to “the rules” as regards to DNS and session shifting. Receiver as an access method was very uniform as a virtualized screen to apps or desktops.

+ RELATED: Free download: A get-up-to-speed guide on VDI +

Citrix XenApp/XenDesktop hides much of its sophistication behind wizards that we found practical for delivering both apps to persistent/non-persistent desktops with even the latest Windows 10 builds, mutable as they are.

As Microsoft adopts more Linux-ish traits, we expect Linux apps and window managers/desktops to be found as virtualized resources. Our sense was that Citrix is ahead of the competition when virtualizing and presenting Linux resources. We like that we were in a very mature platform that behaved predictably. Predictable is good.

Parallels RAS 15

Of the three products tested, Parallels RAS was the most easily configured, yet has most of the features we expected—including the second longest list of supported host virtualization sources and client devices. We published apps, desktops, and shared resources quickly.

Parallels acquired the 2x RAS platform (along with MDM assets) in early 2015, then coupled the 2x platform with virtualization and cross-platform glue of their own, producing what is now Build 15 of Parallels RAS.

Unlike Citrix XenDesktop/App, Parallels runs on Windows 2003-2012 R2 servers and needs a variety of integration steps for the Windows server host operating system, depending on its vintage. Herein lies a catch: Don’t use older servers to host Parallels RAS.