Citrix Connection Error

[tom111]

Hello, we have a strange phenomenon.

We are using a Server Farm with MetaFrame 1.8 on
5 Servers with Windows NT 4.0 and Citrix Clients for our Published Application.
Our problem:
The users start the published application and enter data.
While entering the data all of the fields in the application are cleared from one moment to an other.
Today we found out that after pressing the ESC key the data will reappear in the entry fields. But this cannot be the solution to this problem, just pressing the ESC key.
After a while this problem appears again.
What we cannot understand is, that only users of one country have this problem ( Italy )
and all the others not, even we are using the same Citrix Client version 4.21.779.
The users have all the same setup in our domain and they have all Win95, WinNT 4.0, Win 2000 on their desktops.

Any help is greatly appreciated

Tom111

 

[tom111]

Because nobody is answering I will tell you what we have discovered up to now.
Sometimes we have pings between 500ms and 1200ms.
It seems that the Citrix Client is not able to hold the connection in these moments and we are loosing the connection to the MetaFrame Farm.
Is there anything we can do on Client side or on Server side to avoid these disruptions?
Any other applications like SAP do not have these problems.

 

[Highland]

Can you tell us a bit more about the network connections between the servers and the "problem" clients??!!

Does the connection to the citrix server terminate, do users have to logon again....??? How often does the fault occur...???

thanks...............

 

[tom111]

Thanks for your answer.
Network Connection: 1,5 MBit, like in all other countries,
there are less workstation than in other countries,
sometimes the users have to log on again in the case Citrix looses its connection to the Servers,
sometimes not in case the entered data in the screen disappears.
The fault occurs up to five times an hour.
At the moment there are Network specialists sent by our Service Provider on the site looking for the problem.
During their investigation they discovered pings from the workstations to the servers and back up to 1200 ms even there is no traffic!!
So it seems there is a problem with the routers.
Anyway, if Citrix is so sensitive against these problems and other applications do not, what can I do to force Citrix stay connected after these faults?

 

[Highland]

I'm looking for info for you on the timeout settings...there are two possibilities I think, because ICA is using TCP/IP as it's transport I'm sure there are registry parameters that can be altered to provide a longer "timeout" for connections to the server using TCP/IP, there are also settings in ICA for both IDLE and disconnected sessions....although I'm almost sure that these are irrelevant in your senario as you are losing connection within "active" sessions, these settings are really for clients with an active seesion but no activity to the server for say 30 minutes....it really sounds more of a networking issue and it will be interesting to see if your Service provider finds anything...???? Heres a link explaining Idle/disconnected timeout settings for ICA....

http://www.thethin.net/archive3.cfm?id=73777

 

[tom111]

Thanks again.
We are using the settings mentioned because of the limited user licences we have, we also limited the concurrent session to two per user.
Over night there is a stress test from both sides, Italy and Germany, they have already started with it.
Now we have to wait until tomorrow to have a look at the statistics.

 

[tom111]

Even we have a dedicated connection to the MetaFrame Server Farm for our Citrix Connection the errors occur.
The local network seems to be okay and the provider could not find anything during the stress test.
What we will do now is to expand the bandwidth.
This is the opinion of our network people.
But what I still do not understand we do have the same bandwidth in other countries, sometimes there are more users, more traffic on the line and nobody has problems, and they are all using the same applications.
Is it possible Citrix has a problem with Italian Microsoft Windows?

 

[Highland]

Found the following articles which might help....

http://www.jsiinc.com/subc/tip1300/rh1318.htm

http://www.jsiinc.com/subb/tip0700/rh0730.htm

Also from the Server Resource Kit...

TCP has the following "features"....

Flow control....Both client and server computers participate in the transmission of the packets, which virtually eliminates potential problems with packet overflows and lost packets(!!!).

Acknowledgment....The computer sending data packets expects an acknowledgment message (ACK) from the destination computer. This acknowledgment verifies that the packet was successfully received at the destination.

Retransmission....If the sending computer does not receive an ACK in a specified period of time, it assumes the packet became lost or corrupted and retransmits the packet.

Sequencing....All packets are numbered and sent in order so that the receiving computer reorganizes the data correctly.

Checksum....All packets contain a checksum to ensure integrity of the data. If the data is corrupted somewhere during the transmission, the checksum is used to indicate that the data is not the same data that was sent.

I'm not too sure if the above will help..?? Like you said it seems a bit strange if you have other "countries" connecting to the servers without any problems, adjusting the TCP parameters is only going to affect the performance for everyone..??? Try moving your switch ports for each end of the WAN link...??? It could be something simple like a faulty Switch connection or even faulty network hardware in the Italy office....???

Hope this helps........

 

[Highland]

Meant to add in previous post....

Does anyone have a full listing for the sub-keys available in the following reg key....???

HKLM/SYSTEM/currentcontrolset/services/tcpip/parameters

 

[Highland]

Found some further info on "tuning" IP for WAN links....

http://hqextsrvsft01.citrix.com/cgi...=1,ST=104,N=0005,K=31235,SXI=0,Case=obj(1060)

 

[Highland]

Found some further info on "tuning" IP for WAN links....

http://hqextsrvsft01.citrix.com/cgi...=1,ST=104,N=0005,K=31235,SXI=0,Case=obj(1060)

 

[Guest_imported]

Hello,
I've found on Citrix.com that there is a way to increase the delay before TCP/IP finds a timeout :
documents CTX708444 and CTX757449
in the Knowledge database
I hope it can be helpful