Mostly commonly VLAN tagging is completed at the hypervisor layer within the vSwitch Portgroup configuration so the interface shown to the VPX has VLAN already present.
Where VLAN ID (Optional) is changed to VLAN provided by the Network engineer in the image below:
There is a requirement that to use VLAN Tagging for interfaces when admin partitions are used within Netscalers. But when this is tagged within the appliance the VLAN becomes unusable.
When VLAN is tagged or leave at default of “NONE” then VLAN tagging is not possible within the VPX.
Set VLAN ID (Optional) field in vSwitch to 4095 which essentially trunks all VLAN to the appliance allowing tagging to be completed by the VPX. Once this has been completed VLAN tagging is possible within VPX and admin partition function correctly with there interfaces assigned.
There seems to be some conflicting information from Citrix with 2 different articles
http://support.citrix.com/article/CTX121291 – Says VLAN tagging unsupported with appliable products just listed netscaler. This has been reported to citrix for there review and correction of products that it applies to.
https://docs.citrix.com/en-us/netscaler/10-5/vpx/ns-vpx-overview-wrapper-con.html – This overview states VLAN 4095 must be used for VLAN tagging when using VPX.