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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

578.0. "Dual DECbridge 900MX on FDDI ring" by HGSW32::KKHAU (KK Hau @HGO) Wed Dec 22 1993 05:38

    Hi, There 
    
    We are going to propose DECbridge 900MX to one of our customer. There is 
    a quesetion on Bridge 900MX. Can we config two bridge 900 on the same 
    hub? If yes, how dose the spinning tree works? Does the spinning tree 
    protocol spread thru the whole ring or just the two bridges in e-net. 
    And in which channel that it connected to. The reason for that is we 
    want to hav a resilience connecting, no single point of failure on the 
    design.

    One more question is what is the filtering and forwarding rate of 
    bridge 900MX?
    
    regards
    
    KK Hau/HK DC
    



            +--------+-+-+               +-------+-+-+
            | six    |9|9|               | six   |9|9|
            | 900TM  |0|0| ... total 20..| 900TM |0|0|
            | repeat |0|0|     900 Hubs  | repeat|0|0|
            |  er's  |B|B|               |  er's |B|B|
            +--------+++++               +-------+++++
                      | | Two DAS                 | |two DAS
                      | |  attach                 | |   attach
                   ---+-+-------------------------+-+-----
                   ---------------------------------------
                             FDDI ring
                 
    
    
    
    
    
    
    
    
    
    
T.RTitleUserPersonal
Name
DateLines
578.1should runZUR01::SCHNEIDERRWed Dec 22 1993 08:0936
>            +--------+-+-+               +-------+-+-+
>            | six    |9|9|               | six   |9|9|
>            | 900TM  |0|0| ... total 20..| 900TM |0|0|
>            | repeat |0|0|     900 Hubs  | repeat|0|0|
>            |  er's  |B|B|               |  er's |B|B|
>            +--------+++++               +-------+++++
>                      | | Two DAS                 | |two DAS
>                      | |  attach                 | |   attach
>                   ---+-+-------------------------+-+-----
>                   ---------------------------------------
>                             FDDI ring


It depends your configuration. Each bridge is able to connect one FDDI ring to 
6 Ethernet channels. In your drawing it seems like your FDDI ring is outside of 
the HUB.
Now you have two possibilities:
- Each of your bridge connects the FDDI to only one Ethernet segment. Example 
bridge 1 connects FDDI to Ethernet 1,2,3 and bridge 2 connects FDDI to Ethernet 
4,5,6. In this case all bridges are forwarding, because you have no loop ( no 
redundance).

- Both bridges connect the FDDI to the same Ethernet. Example: bridge 1 
connects FDDI to Ethernet 1,2,3,4 and bridge 2 connects FDDI to Ethernet 
1,2,3,4. In this case you have a loop and spanning tree (btw..not spinning 
tree) makes one of the bridges to go in backup mode.


----> should be no problem.

Remeber: To config the Bridge900 to separate backplane-channels (Ethernets), 
you need HUBwatch 3.0. Availible in spring 94.



Roland
578.2should run and.....QUIVER::GALLAGHERWed Dec 22 1993 13:0019
>- Both bridges connect the FDDI to the same Ethernet. Example: bridge 1 
>connects FDDI to Ethernet 1,2,3,4 and bridge 2 connects FDDI to Ethernet 
>1,2,3,4. In this case you have a loop and spanning tree (btw..not spinning 
>tree) makes one of the bridges to go in backup mode.

.....and this gives you some of the fault tolerance you're looking for.
You have a forwarding bridge and a backup bridge on each segment.  If the 
forwarding bridge fails, the backup bridge will become a forwarding bridge
*after* the time it takes to detect the spanning tree change plus
a configurable amount of pre-forwarding delay.   I believe the spanning
tree converges in a few seconds and the default pre-forwarding delay
is 30 seconds.

>                                                 Does the spinning tree 
>    protocol spread thru the whole ring or just the two bridges in e-net.

The spanning tree works on all bridges throughout the bridged LAN.

						-Shawn
578.3performance?VNABRW::PARGFRIEDERWed Dec 22 1993 13:528
    
    
    never answered...
    
    Does anybody know the forwarding and filtering rates of
    the DECHUB900 FDDI Bridge??
    
    Alfred
578.4QUIVER::SLAWRENCEWed Dec 22 1993 13:584
    As fast as we can make it... :-)
    
    More seriously - it's not done yet, so any numbers would be premature. 
    I doubt you'll be disappointed - those guys are all performance freaks. 
578.5How fast is fast?CGOS01::DMARLOWEdsk dsk dsk (tsk tsk tsk)Wed Dec 22 1993 16:5210
    re. .-1
    
    I have heard some of numbers that they think it will do and suffice
    to say you should be able to have several Enet ports running at full
    theoretical speed (14,880pps) and still have headroom for the other
    ports.
    
    Maybe by Network Academy testing will be done and numbers verified.
    
    dave
578.6LEVERS::ANILWed Dec 22 1993 16:5717
    At FCS of the DECbridge 900MX, the Ethernets and FDDI will not be
    able to "LAN hop", with one exception: an Ethernet port will be
    switchable between the thinwire on the backplane and the front panel
    using the Setup port.  This is only a temporary menu item, not
    manageable by HUBwatch -- as someone else mentioned, an upcoming
    release of HUBwatch is expected to support separate backplane
    LAN connections for each of the Ethernet ports as well as the FDDI.
    In the meantime, external wiring can be used to connect hub repeaters
    and concentrators to bridge ports.

    As far as performance numbers, they should become available soon.
    For advance information on the bridge, please contact the product
    manager Jane Brechlin.. since the product isn't yet announced,
    I'm not sure what information can be made available in a public
    conference.

    Anil