Conference decwet::windows-nt

5890.0. "Slow TCP and TCPWINDOWSIZE" by ODIXIE::RREEVES () Tue Apr 08 1997 13:30

    We are experiencing some very slow performance when attempting to 
    create a new program item from an application on a Windows-NT server.
    
    Sometimes it takes as much as 30 to 45 seconds from the time that 
    we click OK to the time that the message  advising that the "Path may
    not be available" because it is a network drive. Interesting enough,
    the same application copied to a Windows-NT Workstation with a share
    comes back "instantly". 
    
    
    Windows-NT Workstation ---------> creates ICON from NT Server loaded
    				      application is slow!
    Windows-NT Workstation ---------> creates ICON from NT Workstation 
    				      loaded application is fast.
    
    The network sniffer we are using is running in expert mode and is 
    reporting transmission delays. The message the sniffer gives is
    
    WINDOW FROZEN
    
    The TCP/IP Window of this station has been stuck at 8136 bytes for 
    longer than the "Zero Window" threshold of 5 seconds. The maximum 
    window size that has been observed is 8760 bytes.
    
    The documented default for TCPWINDOWSIZE is 8760.
    
    I noticed in one of my Microsoft courses that there is a registery
    entry called TCPWINDOWSIZE which defaults to 8760, but when I look
    into the registery under 
    
    HKEY_LOCAL_MACHINE\system\currentcontrolset\services\tcpip\paramters
    
    the key does not exist.  (Both Workstation and Server). 
    
    Does anyone have a clue why we are experiencing these delays from the 
    server only and if this registery value can affect this ?

    all O/S version mentioned in .0 are 3.51 service pack 5 (Workstation 
    and server)

    Oops, it looks like it as IBM antivirus running on the server.