Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!ncar!noao!arizona!arizona.edu!leonard
From: leonard@arizona.edu (Aaron Leonard)
Newsgroups: comp.dcom.lans
Subject: <None>
Message-ID: <1990Nov8.171924.248@arizona.edu>
Date: 9 Nov 90 00:19:23 GMT
References: <1522@ariadne.csi.forth.GR>
Organization: University of Arizona
Lines: 51

In article <1522@ariadne.csi.forth.GR>, nicolas@csi.forth.gr 
(Nicolas Chrissakis) writes:
> 
> I have  the following situation:
> 
>       |=========================|  <-----Ethernet 802.3
>                  ||||
>                  ||||
>                  |||| <------- 4 wires (600 meters) under a road.
>                  ||||
>                  ||||
>        |========================|  <-----Ethernet 802.3
> 
> I will like to connect the 2 Ethernet segments with these 4 wires.
> I can not put a repeater in the middle of the road and I want to have a
> 10 Mbit/sec connection.

In such situations, we'll drive the line as a T1 circuit and hook up
the Ethernets via bridge/routers, thus:

       |=========================|  <-----Ethernet 802.3
                    |  <---------------AUI cable
                 [bridge]
                    I  <---------------V.35 cable
                  [ld] <---------------T1 line driver
                  ||||
                  |||| <------- 4 wires (600 meters) under a road.
                  ||||
                  [ld] <---------------T1 line driver
                    I  <---------------V.35 cable
                 [bridge]
                    |  <---------------AUI cable
        |========================|  <-----Ethernet 802.3

You can use T1 CSU/DSUs, but on private copper the T1 line drivers
are smaller and cheaper.  (We use units from Teleprocessing Products.)
They can drive the line at speeds ranging from fractional T1 (384Kb I
think) on up to a full 2.048MBps.

You can use bridges or routers to connect the T1 circuit up to the
Ethernet.  Bridges are cheaper; we like cisco brouters for their
flexibility.

The whole thing ain't cheap; our cost (and we get big discounts) runs
to about $10000 for such a hookup.  But it works fine.


Aaron

Aaron Leonard (AL104), <Leonard@Arizona.EDU>
University of Arizona Telecommunications, Tucson AZ 85721