Tag Archives: bandwidth

Latest XenApp XenDesktop bandwidth utilization tests

As many of you saw, XenApp and XenDesktop 7.17 was recently released.  And again, there are statements saying that due to optimizations in the codecs, bandwidth usage rates dropped again.

Is it just me, or does it seem like every few releases Citrix finds ways to further reduce bandwidth consumption. When 7.13 came out, there were statements saying bandwidth utilization dropped. And in 7.17, we are hearing similar remarks.

I wanted to see how true this was, so I ran my own simulations. I decided to run tests against the 7.11, 7.12, 7.13, 7.14, 7.15, 7.16 and 7.17 releases.

Bandwidth Utilization

I know, the lines do get a bit jumbled, but you can see each simulation ran similar workloads as the rises in usage all appear within similar time periods.

To make it easier to see the overall bandwidth reductions, lets switch to a bar graph.

Bandwidth Utilization

Now you can easily see 3 distinct groupings of data:

  1. Group 1: 7.11 and 7.12
  2. Group 2: 7.13-7.16
  3. Group 3: 7.17

So it is true, 7.17 further reduces bandwidth consumption.

Daniel (Follow on Twitter @djfeller)
XenApp/XenDesktop On-Prem Poster
XenApp/XenDesktop Cloud Service Poster
Citrix XenApp and XenDesktop 7.15 VDI Handbook




Virtual Desktop Bandwidth – Revisited

Back in May 2010, I started my Top 10 Mistakes Made with Virtual Desktops. I talked about how much bandwidth certain activities require when using XenDesktop and HDX. The table I provided is great, but it does pose the question, “What does a person do with this information?” Since then, I’ve been able to spend more time and have recently completed the bandwidth planning guide, which you can get by accessing the XenDesktop Design Handbook. But let’s take a closer look at what the planning guide says…

First, we have a list of bandwidth requirements for certain activities (Office work, Internet activities, Flash rendering, WMV videos, etc). I can simply use the following formula to create my average bandwidth consumption:

Estimated Bandwidth=(OfficeBW*%ofTime)+(InternetBW*%ofTime)+(PrintBW*%ofTime)+(FlashBW*%ofTime)+(StdVideoBW*%ofTime)+(HDVideoBW*%ofTime)

The formula works great, BUT it is an average for 1 user. The whole concept of averages is that most of your users will be doing activities that require smaller amounts of bandwidth while a few will consume more.  By averaging them all out, we create a buffer. Let me show you what I mean. First, think of a single user’s day and calculate how much time they spend doing certain activities:

  • Office-based: 4 hours
  • Internet: 1 hour
  • Printing: 15 minutes
  • Flash Video: 30 minutes
  • Standard WMV Video: 10 minutes
  • HD WMV Video: 5 minutes
  • Idle: 3 hours (one hour lunch and two, one hour meetings)

If I use this scenario, the user will require and average of 78Kbps of bandwidth, (43kbps or less for low end and 1812 kbps for high end). If I average this out across hundreds of users within a site, I have a small safety net for those few users who are watching videos.  Unfortunately, because the difference between low usage and high usage is so great, very few users can simulatanously consume high levels of bandwidth before the experience fails.

Hopefully, I’ve explained the dangers of using averages, but that begs the question of how to plan bandwidth requirements.

  1. Start with the averages. That is your baseline.
  2. Define a burst level of required bandwidth. Chances are high that not all users will be watching HD WMV video at the same time. So by creating a 20% safety net (just an example, your safety net will differ) on top of our average bandwidth calculation, we should be able to provide users with acceptable performance, even when watching videos.

Hopefully, this sheds some light onto planning your XenDesktop environment.

Don’t forget to get this planning guide and many others in the XenDesktop Design Handbook.

Daniel – Lead Architect


The Virtual School Is In Session, Please Take your Seats

Once upon a time, there was a little school (70,000 users) with a  little problem (desktops over 5 years old) with a little idea. The school was trying to find a way to make the tax money go further. The newest desktops were 5 years old with many more approaching 10 years.  Depending on the school within the district meant different endpoints, different applications and even different quality.  With so many students having home PCs, the school was also interested in allowing these students to work with their applications while not at school.

The school decided to try something new… desktop virtualization.

But if you had to create a desktop virtualization design for a school or your organization, how would you begin? What would you focus on?  What do you think are the most important design components?  That is what we will focus on during a Ask the Architect TechTalk on June 18th at 1PM Eastern time.  Not only will we focus on the hypevisor, which is Microsoft Hyper-V, we will also focus on the three Citrix FlexCast models used, the image delivery solution, applications integration and how the XenDesktop farm is designed.

There will be many interesting points throughout the TechTalk including this one: Continue reading The Virtual School Is In Session, Please Take your Seats


How Much Bandwidth Do I Need for My Virtual Desktop

Do you ever wonder how much bandwidth you need to do a desktop virtualization implementation? Regardless of the flavor of virtual desktop being implemented (hosted shared, hosted VM-based VDI, local streamed, etc), the network plays a critical role. That should not be surprising (if it is, we need to have an even bigger discussion). If you don’t plan your network bandwidth appropriately, you will have unhappy users, who will make you unhappy.

As we would expect, the user experience degrades as the latency increases and the bandwidth decreases. Proper network planning must be based on the type of work users are performing and the overall network topology. Back in the XenApp-only days, many people used 20 kbps as an estimate for network bandwidth requirements. Can we use that for virtual desktops? NO (although I could configure XenDesktop to only use 20 kbps).
Continue reading How Much Bandwidth Do I Need for My Virtual Desktop