ICA behavior on lossy networks. 1


I guess a picture is worth a thousand words. So what about a video?

Yesterday here at Citrix Synergy 2010 I had the time to record a quick video that shows how ICA, normally a very robust protocol for the WAN, suffers from packet loss. Before you go ahead and say the conditions of the test are not really ‘real world’ all I can tell you (and I can show it in person if you want) is the loss I have seen yesterday over the connection provided by the Marriot Hotel in San Francisco spiked during certain moments to more than 15-20%. So on the real world you will face packet loss at one degree or another. Guaranteed it WILL be there.

This quick test (runs for 6 minutes) shows a XenApp 6 server running on Windows Server 2008 R2 with no load whatsoever. We injected a 3% loss but again, were able to see huge spikes on it (remember, our solution, hardware or software based, sends a beacon between both ends all the time to determine how network conditions are at any given time and adjusts how mildly/heavily we do our magic and with all this data we can plot what is going on over the link in real time).

The results? Well see for yourself. My take on this is XenDesktop/XenApp do suffer. Period. In certain cases your users would experience serious lags when typing, very choppy video/audio and so on. Unusable? I would not go that far. Fixable? Yes as the video clearly shows. And also keep in mind this was all done over a hotel internet connection (the type you get on your room) in a conference where probably every single person IS using the hotel link AND this was done on a XenApp 6 box running in Ottawa, Canada, a couple miles from San Francisco (probably around 3,000 miles).

If you want to understand how we do this (remember, we are a layer 2 solution so we fix ICA, RDP, PCoIP, etc – we do not care what you run; we fix it) feel free to stop me at Citrix Synergy for a chat or just follow me on Twitter (crod).

Bottom line: even though these protocols do have their mechanisms to cope with packet loss, ICA, the king of the kings in the VDI world IMHO, does suffer. If it does, I can only imagine PCoIP will suffer even more (and RDP too). Oh we have tested them.

Yes, they suck.

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