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PacketShaper Traffic Discovery and Citrix Session Reliability

While troubleshooting some performance issues with Citrix sessions between headquarters and sub locations, I decided to take a closer look at the PacketShaper. The PacketShaper is positioned at the headquarter and does outbound shaping to the sub locations. The PacketShaper is using older software (7.2x), which isn’t necessarily a problem.

I deleted the class for a specific location, created the class again and enabled traffic discovery for that class to check which protocols are used by the sub location.

Traffic Discovery: The PacketWise process of observing and creating traffic classes for all packets as they pass through the unit. This process compiles a list of the protocols and applications in use on a network, creating a traffic tree.

Traffic Discovery is working perfectly, because I see different protocols popping up under the sub locations class under which Citrix. In the past PacketShaper had the opportunity to discover the Published Applications or priority bit tagging used with Citrix. This gave you the opportunity to configure shaping parameters per published application.

Nowadays a lot of Citrix customers use Session Reliability. A major drawback of Session Reliability, in conjunction with a PacketShaper, is the encryption of the data stream. The encryption of the data stream prevents the PacketShaper from discovering the published applications or the priority bit tagging.

I first checked if this problem is solved by the latest software release (8.5 at the time of writing), but it isn’t. BlueCoat acknowledges the problem and describes it in this article. The article contains a link to another article about Manage Citrix Performance, which can be useful when using Citrix without Session Reliability.

Disabling Session Reliability isn’t an option for my troubleshooting, so I guess I have to find another way to troubleshoot the performance issues.