peter@julian.UUCP (10/19/87)
We have couple of buildings that happen to have some spare 50 micron fiber cable between them. We want to use this cable to link a set of ethernets via IP gateway boxes (probably Cisco systems). One product that was recommended to us (by Cisco systems) was the model 3030a modem from Codenoll (us$795 each). This seems like a very reasonable price for a 10Mb/sec modem. I'm looking for sites that are using these modems to get some idea about how well they work. Anyone using them? -- Peter Marshall, Data Comm. Manager CCS, U. of Western Ontario, London, Canada N6A 5B7 (519)661-2151x6032 pm@uwovax.BITNET; pm@uwovax.uwo.cdn; peter@julian.uucp; ...!watmath!julian!peter
ron@topaz.rutgers.edu (Ron Natalie) (10/20/87)
We put a pair of FiberCom Whisperlan transcievers into operation recently. These are running over about 2000' of fiber between two buildings here at Rutgers. One end is plugged directly into an IP/DECNET Gateway (CISCO) and the other is plugged into a TCP multiport box which intern has the central gateways (a collection of several CISCO boxes and a VAX 750). The boxes cost about $850 and we haven't had any problem with them. They have the advantage (unlike the Codenol, I believe) of allowing multiple units to be ringed. That is, you can connect three or more of these boxes together using fiber rather than using them as a point to point link. This ends up saving you the price and the overhead of a board in the CISCO box in the middle of the net having to copy packets bridging accross the two fiber segments. There are a number of others coming on the market including one from Optical Data Systems that claims to be selling for under $600. We haven't seen them yet. -Ron
ernie@nucsrl.UUCP (Ernest Woodward) (10/22/87)
> Xref: chinet comp.dcom.modems:946 comp.protocols.tcp-ip:1389 > > We put a pair of FiberCom Whisperlan transcievers into operation > recently. These are running over about 2000' of fiber between > two buildings here at Rutgers. One end is plugged directly into > an IP/DECNET Gateway (CISCO) and the other is plugged into a > TCP multiport box which intern has the central gateways (a collection > of several CISCO boxes and a VAX 750). The boxes cost about $850 I was curious about the TCP multiport boxes. I am aware of several ETHERNET multiport boxes like the DEC DELNI, EXCELAN fan-out box, HP multiport, etc. The reason for pointing this out, is that I currently have an ETHERNET multiport box connected to a CODENOLL 3030A and believe that one could connect several units with two fiber modems and two ETHERNET mutliport boxes, or as in my network, connect several units to one branch of the fiber optic star coupler via one 3030A. > and we haven't had any problem with them. They have the advantage > (unlike the Codenol, I believe) of allowing multiple units to be > ringed. That is, you can connect three or more of these boxes > together using fiber rather than using them as a point to point > link. This ends up saving you the price and the overhead of a > board in the CISCO box in the middle of the net having to copy > packets bridging accross the two fiber segments. I believe that the CISCO boxes allow for one possible network configuration based on internetworking. It is possible to purchase CODENOLL bridge equipment that could connect ETHERNET segments via fiber links, or it is possible to connect as suggested above, i.e. two fiber modems and an ETHERNET multiport box. The multiport boxes require that all the units be within a 45 meter radius of the multiport box. I believe that either CODENOLL or FiberCom or maybe even Siecor ( DEC and Siecor were once selling a system similar to CODENOLL but used different collision detection schemes) offer equivalent opportunities to design the inter- connection with one of three possible methods; gateway, coax to fiber bridge, or multiport to modem. I thinks it will be boil down to a simple cost comparison of equipment prices and features. Sincerely, Ernie Woodward Academic Computing and Network Services Northwestern University
ron@topaz.rutgers.edu (Ron Natalie) (10/26/87)
Multiport boxes are fanouts for transcievers. They do not repeat data between segments. A picture for example: |<-cable-> HOST CABLE-REAL TRANSCIEVER <-Transciever Cable->MULTIPORT BOX |<-cable-> HOST |<-cable-> HOST My application was to hook several buildings together with fiber links. With the FiberCom boxes this looks like: FiberCom <-Fiber-> FiberCom <-Fiber-> Fibercom <-Fiber-> Fibercom in a more or less arbitrary pattern while the Codenoll requires me to run point to point back to a central star or do something like Cod <-Fiber-> Cod <-Cable-> Bridge <-Cable-> Cod <-Fiber->... -Ron