Citrix ICA RTT - Network Latency - Slow performance

[samuele ferro1709158206]

Hi,

 

VD performance is (at times) very slow, there seems to be a "delay" in the actions.

For example:

- Clicking on Internet Explorer also displays the application after 3 seconds
- switch from one window to the other very slow
- very slow mouse movement

These abnormalities occur several times a day.

I asked for a check on the team network, which they assured me of for them
There is no problem on the network.

The "latency" field displayed in CQI logs (actually constant at 2ms) represents the network latency between the ICA Client device and the Server. There are no anomalies in this case.

I monitored the abnormality with the Citrix Quality Indicator application, which, by reading the log file,
It notifies some issues, especially about ICA RTT which has a sometimes very variable value, even over 200ms.
This field represents latency understood as the time interval between a user action and the graphical response displayed.

I have also installed HDX monitor, which has a very high performance rating, not complaining of anomalies.
 

I attach some useful information and part of the logs

 

 

Citrix Director:

 

Receiver version: 14.7.0.13011

 

ICA RTT: 309ms

Latency: 89ms

 

 

 

Logs Connection quality indicator:

 

In detail I can see that connection is initially OK (Strong connection):

Latency ICA RTT: 12ms

Line speed: 216MBps

Latency: High

RTT:high

Connection Strenght: High

 

 

After a few minutes: Poor connection

 

Latency ICA RTT: 228ms

Line speed: 222Mbps

Latency: High

RTT: Low

Connection Streinght:low

 

 

Then return to normal:

 

Latency ICA RTT: 321ms

Line speed: 202MBps

Latency: High

RTT: Inconsistent

Connection Streinght: None

 

 

 

 

Thank you for your help

[Nathan Joseph1709156207]

There are multiple factors that go into the total accumulation of ICA latency in addition to the raw network latency.

 

In an internal use case the largest factors are the client PC time processing the ICA traffic, the network latency, and the VDA time processing the ICA traffic. Externally you also need to add in external WAN latency and the NetScaler processing latency.

 

That in mind, given what you are observing about consistencies in the network latency, I'd suggest investigating the activity taking place on the endpoint and on the VDA at the time you are observing the spikes in ICA latency.

 

I've seen a number of cases where things like peaked CPU utilization on an endpoint is manifesting as delays within the ICA session, or similar scenarios.

[Jacob Dixon1709152413]

Sounds like what you are experiencing is high latency which is causing the slowness. Are these internal or external users? If they are external users and the latency is fine from the user to the gateway, could it be possible latency issues between the gateway and the VDA?

[samuele ferro1709158206]

Hi Jacob,

 

the user are external, the connection is MPLS type and the bandwitch use is about 40%..

[samuele ferro1709158206]

I have investigated,

 

the problem seem to be the latency o ICA Client. Ref. logs.

 

Do you have any ideas on how to solve the problems?

 

Thanks

[Andrew Sommerer1709155901]

Hey Samuele, did you find a solution to your issue?

[samuele ferro1709158206]

Hi Andrew,

 

Unfurtunately I still hove no solution..

[Daniel Iwaniuk1709155513]

Hi,

 

Any update? We experience very similar issue in our XenDesktop environment. CQI several times per hour report high ICA RTT value (>200ms) when network latency is ~5ms and bandwidth ~240MB.

[Roger Eklund]

Nothing new on this? Same here!

[Michael Erb]

Push it up. I got the same experience in my environment.

[Jasper van Zuijlen]

same here

[Hauke Schillemat1709158366]

Push, same here. I opened a ticket at Citrix.

I turned off the hdx adaptiv transport as policy, so the clients conect via tcp and not udp.

In netscaler i disabled dtls at the gateway.

In the next days i will get an engineer at my enviroment, so then we will trace the problem.

Without udp no problem. Dont´t know why...

[Mike Zirbes]

On 4/7/2020 at 5:52 PM, Hauke Schillemat1709158366 said:

Push, same here. I opened a ticket at Citrix.

I turned off the hdx adaptiv transport as policy, so the clients conect via tcp and not udp.

In netscaler i disabled dtls at the gateway.

In the next days i will get an engineer at my enviroment, so then we will trace the problem.

Without udp no problem. Dont´t know why...

I am having this same problem in my 7.15 LTSR environment after upgrading one of the Storefront servers to 1912 LTSR. Did you ever get a resolution?

I disabled DTLS in the netscaler and that seems to have fixed it. Not 100% certain yet.

 

Turns out the upgrade over wrote the default.ica file on the Storefront server. After adding in the appropriate settings for our environment the problem appears to be solved. More testing is happening but things look good.

Update the file:

C:\inetpub\wwwroot\Citrix\HCE\App_Data\default.ica

Add  lines to [Application] section:

 

OutBufLength=1480

udtMSS=1480

edtMSS=1480

; This is to enable Real-Time Transport

EnableRtpAudio=true

; This is to Allow Real-Time Transport Through gateway

EnableUDPThroughGateway=true

; This is to set audio quality to Medium

AudioBandwidthLimit=1-

; UDP Port range

RtpAudioLowestPort=16500

RtpAudioHighestPort=16509