Tag Archives: Adaptive Transport

Your network is hurting your application experience


A few times a year I get addicted to Xbox. Once the kids go to sleep, I can easily spend hours playing Mass Effect, Fallout or Assassin’s Creed.

The games are wonderful and immersive, which is why I spent over 100 hours playing Fallout 3 and another 100+ hours in Fallout New Vegas.  Unfortunately, I’ve experienced some annoying things with these games.  I’ll be in one of the final battles of Mass Effect 3 against the Reapers when the game starts stuttering.  Do you know how hard it is to aim when the system stutters?

Game stuttering, system stuttering or application stuttering is a great way to severely hurt the user experience. How can we reduce app stutters? We need to look at the underlying reason for the stuttering and figure out how to correct.

Network latency and packet loss is a big reason why users might experience stuttering in an application. If a packet gets lost or a packet times out due to high latency, that packet must be retransmitted.  Retransmissions take time. And if you experience a lot of retransmissions, you experience a lot of application stutters.

We’ve already seen how Citrix’s Adaptive Transport impacts

  1. File Copying
  2. Video Viewing

But what does it do to the application experience? See for yourself

Daniel (Follow on Twitter @djfeller)
Citrix XenApp and XenDesktop 7.6 VDI Handbook
XenApp Best Practices
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Your network is hurting your video viewing experience


I just binged watched the first season of “The Expanse”. Awesome! (BTW, the books are even better.)

I would say 90% of my TV viewing is done with streaming media either from Netflix, Amazon or my home library. Nothing is better at ruining a good viewing session than the spinning circle of oblivion as the video stream is being loaded.

Unfortunately, I had the unfortunate experience of watching that spinning circle of frustration multiple times per episode. Running an Internet speed test revealed I had plenty of bandwidth but, for some reason, my latency was through the roof (400+ms).

My solution was to reboot my cable modem and wireless access points throughout my house. This always fixes the problems. I even made it easy for my family to reboot the system when I was traveling.

What I find interesting about this experience is how latency, and not bandwidth, can impact the viewing experience of video content. Lucky for me, the solution was easy… Reboot. But what if the latency isn’t a technical challenge, but more of a physical challenge based on the location of the viewer and the location of the content?

How can we overcome poor network latency and packet loss?

In a previous video that talked about Adaptive Transport, the focus was on file copying.  The results were astounding.

The question now is, would Adaptive Transport also have an impact on the video viewing experience?

Short answer: Yes. Yes it does.

And just in case you were worried about me and my personal happiness, I did fix my home network issues by replacing my WiFi router with better WiFi access points. No more rebooting devices every 2 days.

Daniel (Follow on Twitter @djfeller)
Citrix XenApp and XenDesktop 7.6 VDI Handbook
XenApp Best Practices
XenApp Videos

Your network is killing your file copy performance


We’ve all been there before, rush hour traffic.

You know how it goes. You slowly increase speed to 5mph, then 10, then 15. Excitement is building because you are now going 20mph. Then, out of nowhere, you slam on the brakes and your speed immediately drops back to 0mph. We eventually start over again, 5, 10, 15mph before we slam our foot on the brakes again bringing us to a complete stop.

At this point it is OK to yell “SERENITY NOW!!!

Unfortunately, this is how packets are being sent across the LAN/WAN. This is how TCP functions via the AIMD (Additive Increments, Multiplicative Decrements) congestion control algorithm. TCP slowly increases transmission speed and then drastically falls back when a re-transmission is required due to a timeout, collision or packet loss.

This works fine on a LAN where bandwidth is high, packet loss is low and latency is low. But as latency and packet loss increases, as is common with a WAN environment, TCP is never able to get up to full speed. We are left with only partial utilization of our WAN link.

We see this all of the time when we try to copy a file. On a LAN, the speed of the file copy remains fairly constant, but on a WAN, the bandwidth utilization slowly increases before dropping back to 0, just like rush hour traffic.

Look at what Citrix did!

Adaptive Transport is able to overcome WAN latency and packet loss. It makes a simple task, like file copying, twice as fast as a traditional Windows 10 PC and 3 times as fast as a VMware Horizon desktop.

Adaptive Transport is an alternative to traditional TCP. And it is more than simply a switch to UDP. Adaptive Transport is a newly developed Citrix enlightened data transport optimized for WAN environments by overcoming high latency and packet loss resulting in faster file copying.

protocol

If the network supports the new transport, HDX will use it. If it does not, HDX falls back to TCP.

Daniel (Follow on Twitter @djfeller)
Citrix XenApp and XenDesktop 7.6 VDI Handbook
XenApp Best Practices
XenApp Videos