Citrix published a great document which collect all information about ports that are used by Citrix components. Use this information when desiging or troubleshooting Virtual Computing architecture especially if communication traffic traverses network components such as firewalls or proxy servers, where ports must be opened to ensure communication flow.
The “basic ports” used by main XenDesktop/XenApp components are shown in the picture below:
Document with detailed description of all ports used by each Citrix product can be downloaded from Citrix website.
The netscaler needs to be able to collect STA-ticket from collectors. So the picture is missing the connection to the controllers.