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Conference netcad::hub_mgnt

Title:DEChub/HUBwatch/PROBEwatch CONFERENCE
Notice:Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7
Moderator:NETCAD::COLELLADT
Created:Wed Nov 13 1991
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:4455
Total number of notes:16761

4202.0. "900EF topology counters" by WRAFLC::WOODALL (MACRO is the best.) Thu Feb 06 1997 10:27

    The customer has a large FDDI hub based network with a mixture of
    DEChub 900s and Cabletron MMAC-3, MMAC-5, MMAC-8, and MMAC-PLUS hubs. 
    
    The Decswitch 900EFs in the DEChubs are seeing on average 50 ethernet
    bridge topology changes and 21 FDDI RING INITs per hour.  These never
    show up on the Cabletron hubs.
    
    We got a network general ethernet/fddi sniffer and looked at the
    network.  It sees a bridge topology change and/or a fddi ring init
    every once in a while, but doesn't come close to matching the counters
    in the DECswitch 900EFs!
    
    Can anyone provide insight as to the descrepancy of the counter
    information?  And yes, the network performance is awful.  LAT drop offs
    are very frequent.
    
    Thanks.
    
    Frank Woodall
    on-site Digital consultant
T.RTitleUserPersonal
Name		DateLines
4202.1Let's start with module types in Cabletron hubs...NETCAD::BATTERSBYThu Feb 06 1997 10:536
    Can you describe what module types are plugged into the MMAC-3,
    MMAC-5, MMAC-8, and MMAC-PLUS hubs, especially bridge modules.
    My verry vague recollection of Cabletron's hardware is that their
    implementation of spanning tree may not be IEEE compliant.
    
    Bob
4202.27 different types of cardsWRAFLC::WOODALLMACRO is the best.Fri Feb 07 1997 13:0522
    In the MMAC-3,MMAC-5,MMAC-8 HUBS, there is a mixture of the following
    modules:
    
    		IRBM
    		IRM-2
    		EMME6
    		MME
    		FDDM
    
    In the MMAC-PLUS hubs there are the following modules:
    
    		9F120
    		9F116
    
    
    
    All modules are running the latest microcode from Cabletron.
    
    Does this give you any ideas?   Thanks for you help!
    
    
    Frank
4202.3Some additional suggestions/questions...NETCAD::BATTERSBYFri Feb 07 1997 15:2628
    ok Frank, I've gotten some ideas from a couple of folks back
    here in the LKG ranch. So we're stirring the pot in a manner
    of speaking. What we came up with is the following suggestions
    and/or follow-on questions.
    
    It would be very useful to know the following:
    
    1) the layout of the network
    2) who is supposed to be the root bridge
    3) is the root swapping to another bridge and who is it.
    
    If the following information is given,
    we may be able to pick out the offender or list some possible
    causes, or possible solutions.
    
    Also, the suspicion is (based on the info provided so far), that there
    may be some kind of FDDI interoperbility problem. With all of the
    ring-inits, the thought is that maybe the FDDI port on each switch
    is cycling up and down (which should also explain the network and 
    LAT problems). This in turn will cause each bridge to indicate a
    topology change when the port state changes. Now to verify this
    aspect, it was suggested to check the mib object counter called
    "dot1dStpPortForwardTransitions" on the FDDI port of some of the
    switches. If they are greater than 1, approaching the number of 
    topology changes, then we should be a lot closer to nailing down
    the culprit.
    
    Bob
4202.4Issue taken off line & being worked by NPSS personel...NETCAD::BATTERSBYMon Feb 10 1997 09:167
    This issue has been taken off line and is in the hands of
    the NPSS support folks.
    If the ultimate problem/resolution found can be boiled down to a 
    manageable synopsis, it might be posted here for the benefit of
    others.
    
    Bob