Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!uunet!snorkelwacker!husc6!frooz!cfa.HARVARD.EDU
From: sward@cfa.HARVARD.EDU (Steve Ward, CF)
Newsgroups: comp.dcom.lans
Subject: Re: Ethernet over twisted pair: a summary of the "whys"
Message-ID: <249@cfa.HARVARD.EDU>
Date: 30 Nov 89 20:36:16 GMT
References: <4686@blake.acs.washington.edu>
Sender: sward@cfa.HARVARD.EDU
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There is a major reason we find twisted pair ethernet attractive at our
site:  network bandwidth management and conservation in the face of
growing numbers of remote file server/multiple client workstation
groups.

We already have multiple local backbone cables with departments isolated
behind bridges.  However, callaboration spreads across departments and
divisions, so that we have a growing trend of computer workstation
clusters (be it VMS VAXclusters or Unix/Ultrix/NFS distributed file
system clusters) where the file server and the client workstations are
physically spread between all departments, divisions and possible
geographic locations, and mobile on top of it all!  If the goal is to
keep all such file server clusters isolated on their own ethernet
segment behind a bridge then it is nigh impossible under the conditions
I describe.  Enter twisted pair:  Aha!  Now each node, no matter its
location, get connected to a central wiring hub.  At wiring hub clusters
of machines, independent of physical location, can be placed on the same
segment which can be bridge isolated.

Again, small sites may be able to easily deal with all circumstances
using thinwire or thickwire.  We have hundreds of workstations and must
support the network connection of many such server/client clusters of
workstations.  Twisted pair provides a method to give our users what
they need in terms of connectivity and flexibility while allowing us
to keep local server/client traffic off the backbones.

As a plus, the bridges, repeaters, etc. are automatically located in
our central equipment area where we have our wiring center.  We have
always endeavored to locate all network equipment here but it has not
always been possible.

We are eager to see the further development and maturation of this
network technology.  Like everyone else we are waiting for standards,
both official and marketplace ad hoc.  In the meantime we are testing
and evaluating. (seemingly the almost-fulltime fate of every network
manager and planner).



Steven M. Ward    ward@cfa.harvard.edu