Conference netcad::hub_mgnt

    I am confused by the three FDDI ports on the drawings that you show.  I
    beleive that the DECbridge/DECswitch only has TWO FDDI PORTS, which can
    be set to A/B, or M/S, and directed to the front or back in any
    combination of TWO ports.    (four connectors show up if you have a
    DEChub one docking station, but only two will work at one time)
    
    It is the CONCENTRATOR modules which have the capacity to have A/B as
    the dual ring, and several "M" ports to feed end stations.  A
    Concentrator module can do what you are looking for.  Unless there has
    been a major upgrade in functionality, the DECswitch 900EF has only TWO
    FDDI connectors which can be either A/B, or M/S.  This allows the
    bridge to participate in either a DUAL ring, or a Tree.   But it cannot
    create a Tree, from it's dual ring.  For that, you would need three
    FDDI PHY ports.
    
    JR

    John is absolutely right. You cannot do what you said with a DECswitch
    900EF.
    
    The question is what do you want to do ? Do you already have any
    equipment (perhaps a hub 900) ?
    
    Cheers,
    
    Pedro
    

    Hi,
    
    I'm the culprit that suggested the config in .0
    
    The config is: we have 3xDECswitch 900EF each housed in a DEChub 900MS
    the A/B port of the three DECswitch 900EF are all connected to form the
    classic dual-ring (we'd much preferred a conc but to save $$). 
    
    Now one of the DEChub 900EF also have two more PEswitch 900TX. The
    intention was that the DECswitch 900EF can be set to A/B forward and M
    on backplane (according to memories of some year old experiment) and
    hence would allow the PEswitches to tree onto the DECswitch 900EF.
    
    Does the 900EF not do this? I remember that it was able to do this when
    I was messing around the then new firmware supporting tree and thought
    how remarkable it is that the 900EF can do that.
    
    Anyway, if it won't do it we'd just have to add a DECconcentrator 900MX
    (which we are persuading them to add, so things might not be so
    disastrous, I'd pray hard tonight).
    
    thanx in advance if someone would let me know if I have to donate a
    DECconc or not :(
    
    rgds,
    hw

    >Does the 900EF not do this? I remember that it was able to do this when
    >I was messing around the then new firmware supporting tree and thought
    >how remarkable it is that the 900EF can do that.
        
    Nope, The DECswitch900ef has never been capable of being able to
    do what you propose. The DECswitch supports only 2 FDDI ports that
    can be *individually* assigned to either the front panel or the
    backplane. That means it can have only 2 active FDDI ports at
    any one time, IE: 2 front ports, 1 front panel and 1 backplane 
    port, or 2 backplane ports.
    
    Bob

    Yes, I went back to re-read the FDDICONF.TXT and it's clearly stated. I
    will work on pushing for the DECconcentrator or upgrading of one
    PEswitch to a DECswitch 900EF. If you can help me with just one more
    question:
    
    If the previous config, to get the network up before the
    DECconcentrator arrives, is it valid to use one of the DECswitch 900EF
    (the one without any PEswitch) as a 'master' where it is set as STUMP
    PRIMARY (A/B forward), and the other two is set as NONROOT M (S
    forward, M in backplane). The two S front-panel ports with be connected
    to the A/B of the STUMP PRIMARY. The 900EF with the PEswitch will then
    be able to form a tree in the backplane. 
    
    Would this be a valid and workable config? It is only temporary until
    we can get a DECconcentrator or another 900EF into the place. The site,
    incidentally is in Vietnam, and the screw-up came about because I did
    not have a copy of FDDICONF.TXT with me at the time (not a good excuse,
    but a good reason why we need the EASYnet).
    
    thanx for all the help,
    hw

    Hello.
    
    Your configuration could be easily met, if you don't mind adding a few
    more modules to your dual ring.
    
    I agree with the thought that the Dual ring should not be messed with
    every time you add a module, but until you get a few concentrators I
    would do the following...
    
    a)  I assume that you have three DEChub 900 Chassis, and each Chassis
        has a single DECswitch 900EF module in it.   (The precise config
        not clear from your most recent entry).  
    b)  I assume that you have connected each hub to the next hub using the
        A/B ports of each DECswitch 900EF, and you have NO FDDI on any
        DEChub 900 backplane.
    c)  I assume that in ONE of these three DEChub 900, you want to add two
        new PEswitch 900TX modules.
    
    d)  I assume the your problem is, you cannot get the dual ring to
        include the PEswitch modules, cause they don't have Front FDDI
        ports.
    
    
    I would do the following (until your concentrator arrives)...
    
    a) Leave all hubs the same, except the hub where you are adding the two
    new PEswitch modules.   On that Hub, create an FDDI on the backplane. 
    Change the DECswitch 900EF from A-front/B-front to A-front/B-rear. 
    Attach the "B" leg to the newly created internal  FDDI LAN in the hub.
    
    2) Attach the two new PEswitch modules to the same newly created LAN.  
    
    3) Wait for a concentrator...
    
    This will give you a wrapped ring.  The system will continue to work
    correctly, but you will no longer have fault tolerance, and the failure
    of ANY fiber will cause a ring partition isolating you into two
    separate FDDI rings.  Not a pretty alternative, but it will work for
    the week or so until the new Concentrator modules arrive.
    
    Have I got a deal for you !!   There are five DECconcentrator 900MX
    modules  DEF6X-MA (without any PMD's) in my car right now, that I
    swapped out of a customer site, and cannot use.  If your cost center
    would like them, we could make a transfer.  I would like to get rid of
    them, cause I don't have the space to store them.  I used up all of my
    Mod-PMD's though...
    
    JR
    
    

    Hi John,
    
    Thanx for the note and yes you've got the config right. And your
    wrapped ring idea is much neater than messing with the one I'm thinking
    about. As for your offer of 900MX, that could be deal too but I'd neat
    to talk to the people in the country (I work for South Asia to which
    Vietnam belongs). The good news for you is that if we can persuade them
    to get the conc for the AlphaServers (they've bought 4 AlphaServer 2100
    running TruCluster without telling anyone about the network
    requirements, so we suggested they really would want those babies on a
    dual-homed link to the backbone), it could means getting 2 900MX.
    
    What is the transfer cost? Is that IBP or Std Price? Also are the
    modules in good condition (ie clean, dusty, paw-marks, etc).
    
    rgds,
    hw
    
    ps: where is CBO?

    No Paw Prints.  (But my cats did sniff the cardboard boxes when I took
    the modules into the house...)
    
    I'll contact you by mail.
    
    JR