Re: Localtalk gateway/bridge

[mjmahon@aol.com (Michael J. Mahon)]

william strutts wrote:

>10baseT is called a star configuration because of
>the fact that all cables go to a hub or switch..  I think they went to
>10baseT so that the installers didn't have to worry about routing
>ethernet coax cable throught the job site. If you wanted to add
>a workstation, it requires you to break the network and add a cable
>from the first station to the new station and then from the new
>station to the second station thus restoring the ethernet.  A star
>configuration just requires the installer to put a cable from the
>workstation to the hub without interrupting the network.

When Ethernet (remember thick Ethernet?) first came out, its
daisy-chain cabling was a complete mismatch with the topology
of buildings and building wiring channels.

Electricity, phone wires, plumbing, and HVAC are all set up
as routing trees.  For example, trunks or mains go to wiring
closets in work areas, which fan out to distribution boxes, which
go to individual offices.  The "loopy" daisy-chain style of
interconnect is a very poor fit--remember the Ethernet cables
hanging down from ceiling tiles?  The only reasonable way to
wire an office building for Ethernet used to be to map it as a
star, with "loops" of cable going out to each drop and back to
the central cabinet before it looped out to the next drop, etc.
In this way, a drop fault could be easily isolated without any
disturbance to other users.  (In a daisy-chain, faults tend
to affect everyone on the loop.)

xBaseT solves this problem intrinsically, by being wired as
a tree of stars, with each branch point a hub, switch, or router.

Daisy-chains are nice for an ad hoc "lab" environment (maybe
why LocalTalk worked so well in schools), but do not map well
to permanent office-style installations.

-michael

 Email:  mjmahon@aol.com
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