| 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 | 
    A customer is testing DEFEAs in COMPAQ 4500 dual processor EISA
    servers (triflex bus).
    
    Apparently there is a problem on the triflex bus and DEFEAs have so
    far proved to be more fault tolerant than the competitors tested (incl
    Cabletron) :-).
    
    However the customer is using Windows NT Performance Monitor to
    view the Network Utilisation and is periodically seeing the network
    utilisation drop to zero, almost as if the card stops talking. This
    occurs at high utilisation and also at relatively low utilisation
    (around 20%).  This appears to be a millisecond-glitch that
    does not affect the server's operation.
    
    Is this indicative of something wrong, such as the card resetting
    periodically, or is it normal?
    
    Thank you
    Jeannie
    
    (NT Server 3.51 SP4
    NIC Configuration is Rcv bfr=4 Tx bfr=32 Requested TTRT(ms)=8
    Full Duplex=off)
    
| T.R | Title | User | Personal Name | Date | Lines | 
|---|---|---|---|---|---|
| 2049.1 | NETCAD::STEFANI | Mon May 20 1996 15:34 | 26 | ||
|     >>Apparently there is a problem on the triflex bus and DEFEAs have so
    >>far proved to be more fault tolerant than the competitors tested (incl
    >>Cabletron) :-).
    
    Yes, but Jeannie, that's because Digital FDDI adapters rule (old,
    Yankee expression).  :-)
    
    >>Is this indicative of something wrong, such as the card resetting
    >>periodically, or is it normal?
    
    It's hard to tell whether the adapter is getting reset periodically. 
    You should note that the NDIS 3 specification provides the OS with a
    means to reset the driver/adapter at will and includes a "watchdog
    timer" that is used to see whether the adapter requires a reset.  Even
    without the timer, the NDIS wrapper contains logic that forces resets
    based on certain criteria.
    
    If you see the adapter LED go off for extended periods of time that
    that could be an indication that the adapter is halting and is being
    reset.  You should see Event Viewer messages if that's happening,
    however.  Also, if you put a FDDI LAN analyzer and see the ring
    bouncing because of the FDDI adapter, or if the concentrator or hub
    connection indicates timeouts, that's further indication that something
    is wrong.                                             
    
    - Larry
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