Communication from the XenDesktop site to the client or end user happens over the ICA/HDX protocol. ICA/HDX runs over TCP, and, with the recent acquisition of Framehawk, can now use UDP. You can't really control what happens on the Internet with regard to performance. You can install tools to speed things up, however, and these are within your sphere of control. Implementing a NetScaler Application Delivery Controller (ADC) and CloudBridge WAN optimization can improve performance significantly for certain environments. Both NetScaler and CloudBridge optimize ICA/HDX.
An ADC might get you a improvement in performance of more than 5%. A WAN Optimization Controller might get you a improvement in performance of more than 90%. Using a Content Delivery Network (CDN) can improve performance from 20% to more than 100%.
The real benefit of an ADC in front of a XenDesktop site is the SSL security that encrypts the communication. Load balancing may help improve performance in large...