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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

1851.0. "DEFPA & AS8200" by HGOM11::HELENZHOU () Wed Nov 01 1995 03:48

    Dear Sir,
    
    Could you provide the message of 
    .the bandwidth of the DEFPA PCI-FDDI controller? I know the DEFPA itself is
     32bits. The customer asked when DEFPA exchanges the data with PCI, it is 
     16 bits or 32bits once?
    .The PCI is 32 bits wide currently on AS8200. If the PCI is 64 bits
     in future, how about DEFPA?
    . What is the peek throughput of DEFPA in DMA mode with IP protocol? it
      is important for the customer's critical applicatoin.
    . According to the AS8200 configuration guide, upto 4 DEFPAs are
      supported. The customer wants more than 4 DEFPA on it. Is there any
      way can do it? what's the reason of the 4 limitaiton? due to network
      protocol? or system I/O capacity?
    
    I'm looking to your reply! Thanks ahead!
    
    Reg.
    Helen
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1851.1NETCAD::STEFANIMachines to humanizeWed Nov 01 1995 10:3732
    >>.the bandwidth of the DEFPA PCI-FDDI controller? I know the DEFPA itself is
    >> 32bits. The customer asked when DEFPA exchanges the data with PCI, it is 
    >> 16 bits or 32bits once?
    
    The DEFPA bursts in longwords (32-bits) on the PCI bus.  By default,
    the burst length is set to a maximum of 16 longwords.
    
    >>.The PCI is 32 bits wide currently on AS8200. If the PCI is 64 bits
    >> in future, how about DEFPA?
    
    The DEFPA will still work fine in a PCI slot that supports 64-bit
    devices.  However, the DEFPA can only address up to 32-bits (~4GBytes).
    
    >>. What is the peek throughput of DEFPA in DMA mode with IP protocol? it
    >>  is important for the customer's critical applicatoin.
    
    We've demo'd two Avanti's with DEFPA's point-to-point running Digital
    UNIX at close to line speed (98Mbits/s) over TCP.  It really depends on
    how fast the system is, and how efficient the protocol stack and device
    driver is.  The card at the hardware level can do line speed, and even
    more in full-duplex mode.
    
    >>. According to the AS8200 configuration guide, upto 4 DEFPAs are
    >>  supported. The customer wants more than 4 DEFPA on it. Is there any
    >>  way can do it? what's the reason of the 4 limitaiton? due to network
    >>  protocol? or system I/O capacity?
    
    I'm not familiar with the AS8200, but each DEFPA works independently,
    so I'd assume that the maximum NIC limitation is system, OS, or driver
    specific.
    
    - Larry
1851.2THANKS FOR TIMELY REPLY!BEJVC::HELENZHOUWed Nov 01 1995 23:351