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From: ron@brl-tgr.ARPA (Ron Natalie <ron>)
Newsgroups: net.lan,net.wanted
Subject: Re: Ether to Ether via T1 Microwave
Message-ID: <388@brl-tgr.ARPA>
Date: Fri, 2-Aug-85 13:52:07 EDT
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Posted: Fri Aug  2 13:52:07 1985
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> (I am posting this note for a friend.	-- John Sullivan, sullivan@harvard)
> 
> I am about to ask the apocalyptic question, "How do I connect two
> ethernets via microwave link?" so if you're not interested, now's the
> time to skip the rest of this note.
> 
Use a Vitalink ethernet link.  However it is only 228 KB not T1.
It is a repackaging of the Bridge box.

> Here are some ideas for the T1<->ether mediating magic.  One possibility
> I've heard about is a card from ACC which plugs into a VAX and transforms
> T1 into something understandable.  (Does anyone have any details on this
> card?)  However, this solution inevitably requires two hosts, each of which
> will experience a hefty CPU burden.
We are intending to use this card to link our team of local area nets
at one site to similar remote sites.  The system involves using high
speed dedicated IP gateways (which currently are isi optimums, which
are 68000 on Q bus systems, IBM-PC's would lose).

> Yet another idea (my favorite) is to use some kind of bridge device on
> either end of the T1 link.  Such a box would plug directly into the
> arpanet, and squirt 10megabit ether packets to/from the T1 radios.
> Apparently, Bridge manufactures a similar product (called a "bridge"),
> but it translates ether to a protocol at 1Mhz (perhaps for twisted
The problem is that they flat out run a 68000 without any advanced
I/O concepts like DMA or interrupts.