Path: utzoo!attcan!uunet!lll-winken!ames!mailrus!uflorida!gatech!bloom-beacon!bu-cs!kwe From: kwe@bu-cs.BU.EDU (kwe@bu-it.bu.edu (Kent W. England)) Newsgroups: comp.dcom.lans Subject: Re: high performance, long distance Ethernet bridges Message-ID: <27088@bu-cs.BU.EDU> Date: 7 Jan 89 21:38:31 GMT References: <2369@spdcc.SPDCC.COM> <10832@s.ms.uky.edu> Reply-To: kwe@buit13.bu.edu (Kent England) Followup-To: comp.dcom.lans Organization: Boston U. Information Technology Lines: 41 In article <10832@s.ms.uky.edu> david@ms.uky.edu (David Herron -- One of the vertebrae) writes: >There's that micro-wave product which is being used by Boston U and Harvard >to link their ethernets. At least I think that's the two school, it's one >of them schools up thar in Boston enywey. It supposedly does full-speed >ethernet bridging and the like, but I don't remember any details. There >was an article in LAN magazine sometime in the middle of last year and >around the same time a small flurry of articles here. >-- That's right it was Boston University and Harvard, but now it's Boston University, Harvard, and MIT and we have three Ethernet links up. We are using them as serial links between router interfaces. It is native Ethernet frames over microwave. Our vendor is Microwave Bypass. There is also Microwave Networks and I believe DEC still has a working relationship with M/A-Com on a similar product. This is really a repeater-like product (think of it as an Ethernet segment actually in the ether), but the question was about "bridges". Of course, you can plug bridges, repeaters and anything else you want into this Etherwave, since it looks just like a transceiver interface, so I guess it fits the bill alright. The microwave is 23 GHz, a 2 foot diameter dish, and you need an FCC license and site survey, which Microwave Bypass can do. 23 GHz will go about 8 miles in the northeast, but the Ethernet timing spec limits you to 4.3 miles to avoid undetected collisions. You may find this a limitation. There are also similar Ethernet-on-infrared products now available. These are limited to about 1 km, but you don't need a license and they are quite compact. Just the thing for a backup or a way to get across the street or highway. Kent England, Boston University Standard disclaimer: I have no affiliation with Microwave Bypass other than as a customer and input device.