pjw@anucsd.OZ (Peter Wishart) (10/16/85)
Our department is about to move to another building. In our current
current building we have an ethernet with VMS Vaxen (using DECnet) and
Suns and a Pyramid (using IP) on it. We wish to run our ethernet
connection from our new building to the old and have both DECnet and IP
running between the builings. All the Suns and the Pyramid will be in
the new building plus a VMS 750, the old building will keep numerous
VMS Vaxen and a Unix 4.2BSD Vax. The distance between the buildings is
about 100 meters [of open ground].
The problem is to protect the ethernet (i.e. the machines on it)
between the buildings from bizarre things like lightning strikes.
DEC (Australia) are insisting the only way to do it is to install a
fibre optic link with bridges at both ends. This looks like costing us
upwards of $25K (Australian). This seems to be excessive for just a
link between buildings!
We are looking for a cheaper way of doing this. We recently tested a
small device purporting to be "an ethernet fuse" (it "breaks" the
ethernet when a significant voltage is found on the cable), but it
degraded the performance so badly we had to reject it. How does one
normally run an ethernet between buildings? Can you provide enough
shielding for the cable so that bridges etc are not necessary?
Help ...
Peter Wishart Computer Science, Australian National University, Canberra
CSNET: pjw%anucsd.oz@csnet-relay ARPA: pjw%anucsd.oz@seismo.CSS.GOV
UUCP: {seismo,ubc-vision,ukc,mcvax,prlb2}!munnari!anucsd.oz!pjwhes@ecsvax.UUCP (Henry Schaffer) (10/17/85)
> Our department is about to move to another building. In our current > current building we have an ethernet ... We wish to run our ethernet > connection from our new building to the old ... The distance between > the buildings is about 100 meters [of open ground]. > > The problem is to protect the ethernet (i.e. the machines on it) > between the buildings from bizarre things like lightning strikes. > ... a fibre optic link with bridges at both ends. ... > > We are looking for a cheaper way of doing this. ... Can you provide > enough shielding for the cable so that bridges etc are not necessary? > Help ... > > Peter Wishart Computer Science, Australian National University, Canberra > > CSNET: pjw%anucsd.oz@csnet-relay ARPA: pjw%anucsd.oz@seismo.CSS.GOV > UUCP: {seismo,ubc-vision,ukc,mcvax,prlb2}!munnari!anucsd.oz!pjw Have you looked into putting the cable underground. Some cable can be directly buried, but it is preferable to bury a couple of 4" pipes (plastic is ok) and then pull the cable(s) through it. This appears to be very good protection against lightning, etc. The only problems I've then seen with lightning are a strike on one of the buildings conducted into the underground wires. You also may then have to be concerned about differences between ground voltages in the two buildings. Having the underground "duct work" then allows installation of other wires for the cost of the wires and pulling. --henry schaffer
sheldon@circadia.UUCP (Scott sheldon Bertilson) (10/28/85)
> > the buildings is about 100 meters [of open ground]. > > > > ... a fibre optic link with bridges at both ends. ... > > > > Peter Wishart Computer Science, Australian National University, Canberra I would recommend that you look into Codenoll fiber optic Ethernet modems. The University of Minnesota is using them to tie about 6 buildings together on an Ethernet. The modem acts just like any standard transciever except that it gets you on/off an optical fiber. You can either plug the transceiver into an Ethernet controller or something like the DEC Ethernet Repeater if you just want to tie the 2 segments together. -- Scott (sheldon) Bertilson ...ihnp4!circadia!sheldon