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From: kwe@bu-it.bu.edu (Kent England)
Newsgroups: comp.dcom.lans
Subject: Re: Need source for broadband modem and data link bridge
Message-ID: <61424@bu.edu.bu.edu>
Date: 26 Jul 90 21:58:06 GMT
References: <32106@cup.portal.com> <15699@s.ms.uky.edu> <61315@bu.edu.bu.edu>
Sender: news@bu.edu.bu.edu
Reply-To: kwe@bu-it.bu.edu (Kent England)
Organization: Boston University
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In article <32106@cup.portal.com>, AMillar@cup.portal.com (Alan DI
Millar) writes:
> > Ungermann-Bass broadband systems are proprietary and require
> > U-B gear.  ....
> 
> You'll have to get the broadband modem from UB, but the data link bridge 
> can be from anybody.  UB calls them data link bridges because so many vendors
> (including UB in the past) sell "bridges" that are really routers.  Any 
> protocol-independent bridge will work.  The broadband modem will give you
> a 15-pin AUI connector, which you can hook up to most vendors' equipment.
> 
> - Alan Millar      AMillar@cup.portal.com

	Terminology clash here.  "Broadband modems" don't have AUI interfaces.
If you want a bridge from someone else, you will have to use a U-B Buffered
Repeater (which includes the broadband interface) to attach it to the CATV
system.  Ethernet signals are not bit-repeated onto the broadband.  The
signalling is different and the bit rate is halved.  U-B uses a different
scheme than IEEE-spec broadband Enet.  I think some of those vendors call their
gear "modems".  You can use a simple single channel translator with a U-B
Buffered Repeater, most commonly on mid-split 4A/R channels.

	U-B bridges are bridges.  They never did deliver a marketable router
for IP.  They did a router for their XNS, as I recall, but they never really
got the hang of TCP/IP.

	--Kent