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Conference 7.286::fddi

Title:FDDI - The Next Generation
Moderator:NETCAD::STEFANI
Created:Thu Apr 27 1989
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2259
Total number of notes:8590

1997.0. "DEFPA Full-duplex on SFT III 4.1" by TBJVOA::FUKUHARA_S () Wed Mar 27 1996 01:01

Hello,

  I'm  testing  DEFPA  in Japanese  OS  environment for its document
localization.
  When 'FULLDUPLEX=ON'  is  set on Novell NetWare 4.1J SFT III - the
Japanese version of SFT III 4.10, the following message is displayed.
                                                                    
  "Full Duplex Mode is only supported for POINT-TO-POINT links!!"

Then the system starts with the disable mode. Following the driver's
README.TXT, the mode can be set.  It  is  verified that the links are  
'POINT-TO-POINT',  and  NetWare SFT III  performs  normally  except 
the FULLDUPLEX mode.

  The test environment is:

     PCs        :  DECpc LPx 566       - as IOEngine 1
                   DECpc XL Server 566 - as IOEngine 2
     Adapters   :  DEFPA-AA (Version A01) * 2
     Processors :  486DX(Both)
     Cable      :  BN34B(SC-SC)
     MSL Driver :  DECMSL4X.MSL
                   DEL FDDIcontroller(EISA/PCI) SFT III 4.X 
                   MSL Driver V1.20(951025)

Have I missed something important, or done something rediculous ?
Thanks for any response.

Sachiko

T.RTitleUserPersonal
Name
DateLines
1997.1Bad choice of words for message..MAVRIC::POSTNetwork backed up? Give it more fiber.Sat Mar 30 1996 13:2321
    Howdy,
    
    The message is left over from the early days of the driver when it
    could handle the loss of even a single packet. It turns out that
    if you have full duplex enabled AND are constantly sending very small
    frames back to back, a frame will be lost during the FULL duplex 
    negotiation if the adapters are in a configuration that does not
    support full duplex (ie. through a concentrator ) Since the driver has
    no way of knowing if the adapter is in a point to point configuration
    (in the time allotted by the OS for the driver to initialize) the
    driver warns the user to insure that the adapter is in a full duplex 
    supported configuration.
    
    Full duplex actually has no performance benefit for the driver since 
    the OS never comes close to line speed data rates over the MSL link,
    so there really is no reason to enable it.
    
    
    I hope this helps...
    
    -Don 
1997.2to be clear...MAVRIC::POSTNetwork backed up? Give it more fiber.Sat Mar 30 1996 13:266
    Just to make it clear, if the switch is set to =ON then the adapter is
    running in full duplex mode. The message should probibly say:
    
    "Adapter running in Full Duplex Mode. Valid for point-to-point links only."
    
    -Don