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From: woody@ucscb.UCSC.EDU (Bill Woodcock)
Newsgroups: comp.dcom.lans
Subject: Re: 10Base-T hubs
Message-ID: <14740@darkstar.ucsc.edu>
Date: 20 Apr 91 02:24:37 GMT
References: <1991Apr15.214932.9635@jhereg.osa.com> <1991Apr16.182217.6151@netcom.COM> <1991Apr17.212748.7165@shl.com>
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        > jbreeden@netcom.COM (John Breeden) writes:
        > A frame sent to a specific mac address only
        > shows up at the port that mac address is
        > attached to. All other ports get the header
        > with the data field blank! (filled with 1s &
        > 0s) - you can't capture other people's
        > traffic! only your own!
      
        > phil@shl.com (Phil Trubey) writes:
        > Has anyone heard of a product that does per
        > port *bridging* inside a 10BaseT hub instead
        > of per port repeating?  ie. Packets would be
        > sent into the hub and the hub would switch it
        > out to the sole destination port. With a fast
        > enough bridging unit, you could up the
        > bandwidth of your ethernet hub by an order or
        > magnitude or two...
    
    There is one AppleTalk hub out that does  this,  and  more  have  been
    rumored.   Although  this  is potentially neat, it makes a hash of the
    heirarchical models we're used  to  using  when  we  think  about  our
    networks.  It bottlenecks any transmissions to faster media, (FDDI, in
    this case, instead of Ethernet) and  it  renders  all  your  expensive
    network  troubleshooting and packet analysis utilities useless. If the
    hub's management software is, in and of itself, smart enough  to  give
    you  those  same  features,  (as  is  partially  the  case  with Tribe
    Computing's AppleTalk hub) then you're partially off the hook, but how
    many  Ethernet  hardware  comapnies  would  you  trust  to  write good
    software?  The only way to get around the gatewaying bottleneck is  to
    add  multiple  gateways  per hub, which greatly complicates addressing
    and troubleshooting, and starts costing _a lot_.
                             
                            -Bill Woodcock
                             BMUG NetAdmin

________________________________________________________________________________
bill.woodcock.iv..woody@ucscb.ucsc.edu..2355.virginia.st..berkeley.ca.94709.1315