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 and 1811 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	206 kbps	117 kbps	262 kbps	99 kbps
7.12	212 kbps	123 kbps	263 kbps	96 kbps
7.13	196 kbps	114 kbps	266 kbps	74 kbps
7.14	200 kbps	119 kbps	263 kbps	80 kpbs
7.15	202 kbps	106 kbps	261 kbps	74 kbps
7.16	200 kbps	122 kbps	269 kbps	82 kbps
7.17	198 kbps	103 kbps	96 kbps	28 kbps
7.18	185 kbps	88 kbps	97 kbps	28 kbps
1808	184 kbps	92 kbps	103 kbps	28 kbps
1811	186 kbps	88 kbps	103 kbps	28 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 PolicyLet’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 – ComparisonBy looking at average bandwidth utilization across the 60 minute test, we can start to see these improvements a little easier.Task Worker – User Experience PolicyIn 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 7.17, 7.18 and 1808 releases 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 – ComparisonWhen 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: 7.17-1811

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