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From: gassman@jedi.DEC
Newsgroups: net.lan
Subject: Repeaters, Bridges, Routers, and Gateways
Message-ID: <1174@decwrl.DEC.COM>
Date: Sun, 16-Feb-86 17:34:01 EST
Article-I.D.: decwrl.1174
Posted: Sun Feb 16 17:34:01 1986
Date-Received: Tue, 18-Feb-86 03:23:48 EST
Sender: daemon@decwrl.DEC.COM
Organization: Digital Equipment Corporation
Lines: 59



WHOA... it's time to have a few definitions standardized!

>Newsgroups: net.lan
>Path: decwrl!amdcad!cae780!ubvax!skip
>Subject: Re: Baseband <--> Broadband gateways
>Posted: 13 Feb 86 18:41:31 GMT
>Organization: Ungermann-Bass, Inc., Santa Clara, Ca.
>Summary: Depends on network layer protocol
 
>Bridges get involved at the network layer.  IEEE 802.3 & 802.4 only
>specify up through the data link layer.  What bridge you need depends
>on what network layer protocols you need.  For example, Ungermann-Bass
>provides networks based on a variety of different protocols.  Which
>bridge software you get depends on which network protocols you're using.
>Like Ungermann-Bass's, Bridge's and DEC's bridges will only work on
>networks that use their protocols.  Fortunately, we've all started basing
>our products on standard protocols, so depending on your system,
>vendor A's network interface units may communicate using vendor B's
>bridges.
> .
> .
> .
>-- Skip Addison
>   {lll-crg, decwrl, ihnp4}!amdcad!cae780!ubvax!skip
>   Ungermann-Bass, Inc
>   (408) 496-0111


Skip Addison of Ungermann-Bass is greatly mistaken about
what DIGITAL's LANbridge 100 will do.  He states that DEC's
bridge works at the OSI Network layer, and is therefore protocol 
dependent.  THIS IS NOT THE CASE!!!!  BRIDGES work at the OSI 
datalink layer, and therefore MUST BE PROTOCOL INDEPENDENT.
DEC's LANbridge 100 is indeed so.  What Ungermann-Bass sells as a 
BRIDGE is actually a ROUTER, a router being a protocol DEPENDENT 
device working at the network layer.  UB has been told this often
at trade shows.  What is happening is that the marketplace is being
confused.  In addition to repeaters and bridges, DIGITAL also 
sells routers to forward DECnet protocol packets between LANs 
of 802.3 and/or 802.4.  

DIGITAL's bridge forwards to the 'B' LAN, *ANY* packet who's 
destination station is not on the 'A' LAN.  There also is optional 
bridge management software to do protocol or multicast filtering.  
Two models exist.  One with two ethernet plugs, and one using up to
2000 meters of fiber optics.  Sorry for the commercial, but putting 
out misinformation about LAN products is not helping the standardization 
cause at all.  REPEATERS, BRIDGES, ROUTERS, and GATEWAYS are words
that vendors and users must all agree on, while we trek towards OSI.
Skip, please contact me about how DEC and UB can start to agree on
what we call standard products!  

Bill Gassman
Networks and Communications
Digital Equipment Corp.
(603) 884-0192