Latest XenApp XenDesktop bandwidth utilization tests

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. If we look at the latest releases, we see the following major improvements to the ICA protocol

• 7.13:
  • Introduce glyph detection/caching algorithm – Beneficial for text-based workloads
  • Improve scroll detection
• 7.17:
  • Update glyph detection/caching algorithm – Beneficial for text-based workloads
• 7.18:
  • H.264 Build-to-Lossless – Beneficial for graphically interactive sessions
  • Progressive Display – Beneficial for low bandwidth and/or high latency connections

I want to see how these improvements impacts network utilization, so I ran my own simulations. I decided to run the same tests against the 7.11, 7.12, 7.13, 7.14, 7.15, 7.16, 7.17, 7.18, 1808, 1811 and 1903 releases.

Bandwidth Findings

In case you don’t wish to look at the graphs and details, here are the high-level findings for each release

Release	Knowledge Worker User Experience	Knowledge Worker WAN Experience	Task Worker User Experience	Task Worker WAN Experience
7.11	196 kbps	108 kbps	273 kbps	97 kbps
7.12	214 kbps	113 kbps	268 kbps	100 kbps
7.13	202 kbps	116  kbps	273 kbps	77 kbps
7.14	203 kbps	128 kbps	277 kbps	81 kpbs
7.15	204 kbps	99 kbps	270 kbps	78 kbps
7.16	202 kbps	126 kbps	288 kbps	86 kbps
7.17	205 kbps	95 kbps	98  kbps	29 kbps
7.18	174 kbps	82 kbps	100 kbps	25 kbps
1808	177 kbps	91 kbps	103 kbps	28 kbps
1811	183 kbps	87 kbps	103 kbps	27 kbps
1903	171 kbps	79 kbps	102 kbps	27 kbps

Knowledge Worker – User Experience Policy

In the first graph, we have the following:

• Workload: LoginVSI Knowledge Worker
• Policy: Optimize for User Experience
• Test Duration: 60 minutes
• Sample Period: 1 second

I notice the following:

• 7.13: A slight drop in cumulative bandwidth usage. This drop extends through the 7.17 release.
• 7.18: A noticeable drop, most likely due to the H.264 Build-to-Lossless capability with the graphical knowledge worker workload.

Knowledge Worker – WAN Policy

Let’s change the policy and retest

• Workload: LoginVSI Knowledge Worker
• Policy: Optimize for WAN
• Test Duration: 60 minutes
• Sample Period: 1 second

Besides lower numbers, as we would expect with the optimize for WAN policy, we see similar bandwidth reductions in the 7.13 and 7.18 releases.

Knowledge Worker – Comparison

By looking at average bandwidth utilization across the 60 minute test, we can start to see these improvements a little easier.

Task Worker – User Experience Policy

In the first graph, we have the following:

• Workload: LoginVSI Task Worker
• Policy: Optimize for User Experience
• Test Duration: 60 minutes
• Sample Period: 1 second

WHAT???

The releases after 7.17 look crazy. This would be due to the improvements in glyph caching, which is extremely beneficial for text-based workloads, like Excel. I compared the steep increases in the 7.11-7.16 graphs with the actual workload. Turns out these all align with Microsoft Excel. Imagine scrolling through a spreadsheet full of numbers. The glyph detection/caching improvements in 7.17 really shine on this portion of the simulation.Task Worker – WAN PolicyIf we change the policy to WAN and retest

• Workload: LoginVSI Task Worker
• Policy: Optimize for WAN
• Test Duration: 60 minutes
• Sample Period: 1 second

We see similar reductions in the 7.17 release. In addition, we also see the introduction of the glyph caching in the 7.13 release with the optimize for WAN policy.

Task Worker – Comparison

When we change the graph to look at the estimated kilobits per second, the improvements are quite interesting for the Task Worker.

Based on all of these tests, workload changes and policy changes, there are essentially 3 distinct groupings of data based on improvements made to ICA:

• Group 1: 7.11 and 7.12
• Group 2: 7.13-7.16
• Group 3: 7.17-1903

Stay tuned as I plan to keep running these standard tests on upcoming releases.Daniel (Follow on Twitter @djfeller)
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