Expert: Window Frozen

[NWTC]

I am working in a mixed environment of NT4.0 and Novel 5.0. There is still some IPX traffic on the network. Our IP sniff revealed several instances on long delays when running SQL applications on the server from a workstation. These delays were up to 6 minutes in length. These processes should have run in 1-2 minutes.

The sniff shows at these times there was the message "Expert:Window Frozen". What is the cause and is there a correction we can make?

 

[wybnormal]

Window frozen means the ( if I got this right).. the TCp sliding window has not adjusted over a period of time and the packet size has remained the same...

I get these errors and the packet size remains about 60 bytes in size.. thank you bad SQL app :-( Instead of loading up the data into a nice fat packet of 1518, the app in this case chops everything into little bitty 60 byte packets... bad app!! bad app!!

MikeS Find me at

http://www.packetattack.com

"Diplomacy; the art of saying 'nice doggie' till you can find a rock" Wynn Catlin

 

[jrsavage]

Below is the actual sniffer expert explain of the error

Window Frozen

In a windowing protocol (such as DECnet or TCP), the window size of this station has been stuck at some number of bytes for longer than the Window Frozen Time threshold.
When a window is stuck, data flow will not be as efficient because the transmitter will not send data in excess of the current window size.
Possible causes:

1 There is insufficient buffer space, because the recipient's memory allocation process is not providing enough buffer memory.

2 There is insufficient buffer space, because there are new open connections, so that the buffer space must be shared.

J.R. Savage

 

[wybnormal]

Hey JR- let me add one thing here.. I know what the *expert* says but dont take it as gospel.. in my case I have a badly written SQL app that excels at sending each command in a sequence of 64Byte packets.. everytime this happens, I get the warning about a stuck window.. it has nothing to do with buffers.. just crummy programming. Citrix does the exact same thing so the sniff trace shows a ton of these *errors* and over 55% of the total traffic under 256Byte packets..

MikeS Find me at

http://www.packetattack.com

"Diplomacy; the art of saying 'nice doggie' till you can find a rock" Wynn Catlin

 

[Sniffmaster]

Hi,
also if you jump from one window(or app) to another window(or app) and the other is waiting for input.. frozen window

 

[jrsavage]

WYB,

I agree with your example. I've seen quite a bit of crummy programming myself.

Another thing to bear in mind is that "symptoms" in themselves are relatively minor issues which may or may not indicate a larger problem. That's why you may see large numbers of a particular symptom but no diagnosis based upon those symptoms.