Users are facing high latency issue and they are not able to do audio and video calls.

Apps and Desktops ICA streams performs poorly and high end-user experience is observed

"HDX Latency" calculations made by VDA fluctuate up/down from 10ms to 900+ ms observed using command "ctxsession -v" and CitrixCQI tool.

The NetScaler AppFlow HDX L7 latency calculation and VDA HDX Adaptive Scaling feature can’t be enabled simultaneously.

There is an enhancement request created, Citrix is working to come up with a solution between VDA and NetScaler teams.

Workaround:

Disable HDX L7 Latency metric on NetScaler.

From the shell do #nsapimgr -ys enable_ica_l7_latency=0 

Note: This command will not persists through reboots.

Impact of workaround: 

ADM is unable to show client - gateway & snip - vda latency independently, and will show only end-to-end data path latency client - vda

You may monitor "HDX Latency" from the VDA machine using command: "ctxsession -v" or using the CitrixCQI tool

Problem Cause

NetScaler AppFlow HDX insight L7 Latency calculation & VDA Adaptive Scale feature conflict with each other creating an incorrect latency metric forcing the VDA to reduce the output buffer and reduce ICA traffic performance trying to adjust the stream to a non-existent problem.

Described in detail here: https://docs.citrix.com/en-us/citrix-virtual-apps-desktops/2203-ltsr/whats-new/cumulative-update-1/fixed-issues.html 

[CVADHELP-19781] :: This fix allows you to use the legacy NetScaler L7 latency measurement when the HDX Adaptive Scaling feature is disabled. The NetScaler L7 latency and VDA HDX Adaptive Scaling features can’t be enabled simultaneously.