geof@imagen.UUCP.UUCP (05/21/86)
Sorry that this is a little off the topic, but someone on this list probably knows the answer to this question. We are in need of a way to extend our network across a conduit to an adjacent building. To simplify matters, we'd like to use an "ethernet extender" device that hooks two halves of an ethernet together with a fiber optic cable and looks like a repeater (?). I seem to remember that something like this exists, but I don't remember much about it. Does anyone know about such a product? Does anyone have clever ideas of how to connect two ethernets in different but adjacent buildings (don't bother to tell me about gateways, I know about them). - Geof Cooper Imagen
FTD%MIT-OZ@MC.LCS.MIT.EDU.UUCP (05/21/86)
Dec makes one but I don't have the part number.
SRV.MDC@OFFICE-1.ARPA (05/21/86)
Digital Equipment Company sells two ethernet repeaters. Their local ethernet repeater (DEREP-AA) can connect two 500 meter segments of Baseband Ethernet coax. Their Remote Ethernet Repeater (DEREP-RA) uses a fiber optic cable to connect two segments that are up to 1000 meters apart. I got these out of DEC's Networks and Communications Buyer's Guide. Your local DEC rep should be able to get this for you. I am not affiliated with DEC in any way other than using their products. Stephen Veit (Veit@Office-1)
hoffman%pitt@CSNET-RELAY.ARPA (Bob Hoffman) (05/21/86)
Fiber optic Ethernet extenders are made by American Photonics, Inc.;
71 Commerce Drive; Brookfield Center, CT 06805; 800-626-5745 or
203-775-8950/8955.
Their RL6000 series of Ethernet repeaters will connect two segments
of a V2.0 or IEEE 802.3 Ethernet LAN by way of duplex optical fiber
cable up to 1000 meters in length. Price is around $4K/pair.
I have not used these units, but we are considering their purchase to
link up two Ethernets on campus. Another department at Pitt has
purchased T1 multiplexers from API and they are satisfied.
--
Bob Hoffman, N3CVL {allegra, bellcore, cadre, idis, psuvax1}!pitt!hoffman
Pitt Computer Science hoffman%pitt@csnet-relaygeof@imagen.UUCP (Geof Cooper) (05/21/86)
Much thanks for the 15 or so immediate responses. To summarize, people have mentioned that repeaters and half-repeaters (sometimes called "remote repeaters) are available as products from DEC, Xerox, Ungerman Bass, American Photonics (actually, this last one is a fiber extension of the Ethernet transceiver cable (between the tap and the host)). One idea suggested was to run low-cost ethernet coax between buildings, with a half repeater on each side of it. DEC's products were by far the most frequently mentioned. Several people said they have one or the other product installed and working. There were two products mentioned. One was the DEREP repeater, which is "intended for exactly the type of use you describe (to link buildings where there may be a ground potential difference, perhaps a small conduit, and a moderate distance (I forget the max, but it is something like 1000M I think))" [JSPEAR@AI.AI.MIT.EDU]. The other was the Lanbridge-100, which seems to be something more like a "transparent gateway" -- it peeks at network traffic and selectively relays information. It apparently has a fiber optical extension available as an option. The DEREP-RA Remote Ethernet Repeater cost $4,400 (for both halves) in September '85. However, "it seems to be slightly divergent from the Ethernet specs in that it only seems to work properly when connected to the coax with a DEC transceiver (H-4000). Aside from that problem, we've had one in use...without troubles [mckenzie@j.bbn.com]. Thanks again, - Geof Cooper Imagen
leong@PO1.ANDREW.CMU.EDU (John Leong) (05/22/86)
DEC, Ungermann-Bass (UB) and American Photonics (API) make both local and remote repeaters. All the remote repeaters use fibre optic cables. DEC and UB requires 100 micron cable while API is engineered for 50 micron. (Phone companies had been busy putting in 50 micron cables. They are now changing to 62.5). One thing you should know is that when you connect a 100 micron light source into a 50 micron cable, you lose 75% of your light !!! API has an Ethernet extender which is really a long fibre drop cable transceiver and is quite cute. If you want to join two nets together but do not want to sum up the traffic, you can investigate into the LANbridge from DEC. They sell both a local as well as a remote version (or you can use a local version with the API Ethernet extender). I really like the LANbridge better than plain repeater since they will relay only applicable packets to the other side. However, they do cost $$$$. (roughly $8,000 list) John Leong
dardy@NRL-CSS.ARPA (Hank Dardy) (05/23/86)
We have been using the Digital DEREP fiber repeaters for close to two years without problem. The fiber has withstood both nature and man made electrical surge (we have a plasma physics group next door). Our installation has over 120 machines connected thru a "virtual" ethernet composed of broadband, baseband and fiber. Hank
swb@TCGOULD.TN.CORNELL.EDU.UUCP (05/24/86)
John: American Photonics told me they could handle 50, 62.5 or 100 micron fiber -- and indeed sold me some RL5002s for 62.5 micron. Scott