Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!rutgers!topaz.rutgers.edu!ron From: ron@topaz.rutgers.edu (Ron Natalie) Newsgroups: comp.dcom.lans Subject: Re: request for broadband info Message-ID: <12471@topaz.rutgers.edu> Date: Fri, 5-Jun-87 13:54:24 EDT Article-I.D.: topaz.12471 Posted: Fri Jun 5 13:54:24 1987 Date-Received: Tue, 9-Jun-87 07:15:48 EDT References: <4663@columbia.UUCP> Organization: Rutgers Univ., New Brunswick, N.J. Lines: 65 Keywords: broadband Rutgers, The State University of New Jersey (one of these days I expect to see Princeton T-shirts that say "not the state university" on them) has installed a three cable broadband system on the Busch campus (this campus houses the computer center and most of the engineering/sciences). Currently only one cable is live (amplifiers in place, on etc...). That cable is mid-split with the head end located in the main machine room on campus. We currently have two data users on the broadband. The first is a GI point to point RF modem which is not significant. The second is an Applitek broadband networking system. The Applitek bridges ethernets in various buildings in a protocol independent way. Since we have had problems with the Applitek in the past, I have recently been resurveying the market. APPLITEK: The Applitek is will bridge ethernets accross the broadband. It occupies one 6 MHz channel and the RF modems in it are software frequency selectible. The box plugs into a standard Ethernet transceiver on the LAN. It provides packet filtering in much the same fashion as products such as the DEC LANBRIDGE. It has a small amount of monitoring and control that is accessable via an RS-232 port on the back of the box. BRIDGE: Bridge makes a similar system. Essentially, this is their ethernet link level bridge again with broadband modems that come from a company that they have since bought out. They also occupy a single 6 MHz channel and provide about 5 MHz of bandwidth. The boxes again filter out packets which need not travel accross the entire system. The modems are agile across 5 channels. The network may be monitored with the same facility used for their other products (it is a UDP telnet-like facility that lets you talk to the processor in each box). CHIPCOM: Chipcom makes a product called the Ethermodem. This box simulates a transceiver (actually you can get it with two transceiver ports) and provides the full ethernet bandwidth over a non-configurable 18 MHz channel. These boxes actually act as true ethernet transceivers and hence are subject to the normal ethernet distance limitations (unlike the previous two units) for the entire network. In addition, you will need a minimum of a Ethernet repeater to interconnect the it to a local Ethernet although they recommend the DEC LANBRIDGE for packet filtering. The prices for the three are roughly comparable. Expect to pay about $6000 for headend equipment and about $10,000 for each Ethernet you wish to connect to the broadband. Both the CHIPCOM and BRIDGE products come with good reliability and performance references. While our Applitek system is pretty solid now, we did have problems with it in the past. In my investigations I have found this to be pretty universal, other people had Applitek systems that used to be bad, I guess that one of the engineering changes cleared up whatever was causing the reliability problem. The CHIPCOM and BRIDGE products claim that they require their own translater/remodulator, which I find unfortunate. The Applitek seems happy with our existing CATEL (K-TEL?) translator. I'd be interested in hearing other peoples experiences. I know that the following people are bridging ethernets on their Broadband network: University of Maryland U.S. Army - Dover NJ Stanford University University of Wisconsin Arizona State MCNC (Research Triangle, NC - I never remember what the acronym means)