johnl@godot.UUCP (10/18/84)
We're about to move to new offices and are tyring to figure out the
best way to hook up all of our PCs via Ethernet. We're using the 3COM
cards in PCs, so either thick or thin Ethernet would be possible.
There seem to be a few possibilities:
1. Use thin Ethernet with a loop sticking out of the wall in each office.
This looks messy, and is quite fragile when people accidentally step
on their thin cable. Also, I'm not sure that 300 meters will be enough to
dive down into each office from the ceiling and back, so we'd need a
repeater or two. Ugh. Hard to reconfigure, since you have lots of cable
fragments coming up from one office and down into another.
2. Thick ethernet. Possible, but expensive with all the transceivers
and chunks of cabling.
3. Thick ethernet with cluster transceivers. Probably the best bet. The
offices are arranged so it should be possible to have 7 or 8 offices
within 150 cable feet of a single point all attached to a cluster
transceiver.
So there are two questions. First, have we overlooked something? Second,
what sources are there for cluster transceivers? I know about the DELNI,
but I know I saw a cluster transceiver at Intel a few years ago that was
made by somebody else. Also, anybody try plugging a 3COM board into a
DELNI? Will it work? What about the famous current rush that crashes Vaxen
when you plug in the transceiver -- can a 3COM board handle it?
John Levine {decvax!cca | yale | cbosgd | ihnp4 | amd }!ima!johnl
Levine@YALE.ARPArpw3@redwood.UUCP (Rob Warnock) (10/20/84)
+--------------- | 3. Thick ethernet with cluster transceivers. Probably the best bet... | | So there are two questions. First, have we overlooked something? +--------------- No. I agree that clustered transceivers is a good topology. (The term I am used to is "transceiver multiplexer".) The "bunches of grapes on a vine" turns out to match office environments well. (Note that most [all?] ring networks end up with this effective topology as well, with the actual "ring" entirely inside the cluster box!) +--------------- | Second, what sources are there for cluster transceivers? I know about the | DELNI, but I know I saw a cluster transceiver at Intel a few years ago that | was made by somebody else... | John Levine {decvax!cca | yale | cbosgd | ihnp4 | amd }!ima!johnl | Levine@YALE.ARPA +--------------- Try TCL Inc. in Santa Clara, CA. (They may have moved to larger quarters, but area 408 directory assistance has their phone number, I'm sure.) They make the transceivers Xerox ships, and they also make an 8-port mux that can be stacked two levels to get 64 stations per "real" tap. I believe that a fully-loaded 8-port unit is about $1000. (In fact, who needs Ethernet cable?!? ;-} ) Rob Warnock UUCP: {ihnp4,ucbvax!amd}!fortune!redwood!rpw3 DDD: (415)572-2607 (*new*) Envoy: rob.warnock/kingfisher USPS: 510 Trinidad Ln, Foster City, CA 94404 (*new*)
smb@ulysses.UUCP (Steven Bellovin) (10/22/84)
We've successfully used a 3Com *UNIBUS* board with a DELNI.