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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

1178.0. "Is a "single" Ring possible?" by VAXRIO::ROLF (Vaporware Design Specialist) Thu Dec 09 1993 13:31

    This may sound strange, but could I connect two DB528 over just
    ONE pair of SMF?
    
    Or will this trigger off some sort of alarm right away?
    
    Note, there is nothing else on the FDDI ring, only the two bridges.
    
    Rolf, DEC Brazil
    
T.RTitleUserPersonal
Name
DateLines
1178.1KONING::KONINGPaul Koning, B-16504Thu Dec 09 1993 14:5417
Yes.

Think of it this way: connect the two bridges in the usual way, via two pair
of fiber.  You have a normal dual ring.

Now disconnect one pair.  You have a broken connection in the dual ring.  The
dual ring offers (single) fault tolerance: it wraps.

So the single connection works.  You have to connect A to B.  Network management
stations may give you a warning about this, because you have a wrapped ring,
which is normally caused by a fault.  But it is legal and will give you
perfectly normal operation.  It has no fault tolerance, obviously...

To save a little money, you might use one 524 and one 526; that way you only
pay for two single mode transceivers rather than four.

	paul
1178.2ThanksVAXRIO::ROLFVaporware Design SpecialistFri Dec 10 1993 06:523
    Thanks Paul!
    
    Rolf