Newsgroups: comp.dcom.lans
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From: jal@acc.flint.umich.edu (John Lauro)
Subject: Re: 10Base-T hubs(now Bridging)
Message-ID: <1991Apr27.190804.12324@engin.umich.edu>
Sender: news@engin.umich.edu (CAEN Netnews)
Organization: University of Michigan - Flint
References: <14740@darkstar.ucsc.edu> <1991Apr21.021222.947@engin.umich.edu> <1991Apr26.032625.26585@netcom.COM>
Distribution: usa
Date: Sat, 27 Apr 1991 19:08:04 GMT

In article <1991Apr26.032625.26585@netcom.COM> cmilono@netcom.COM (Carlo Milono) writes:
>       Ah, filtering is one thing, but forwarding is another and is
>always slower by quite a bit!

A high speed bridge should be able to forward at number of ports * ethernet speed / 2.
Even if it can only forward at FDDI speed, it would be better than putting all those ports
together.

>       And, when you bridge, you are going to bridge to all others? 
>I suppose what you are asking for is a *star* arrangement, much like
>RS232-C, that supports *private* 10Mbps to a server from the client.

No, a *private* 10Mbps to the hub.  A server would have it's own private
10Mbps connection to the hub.  A packet enters one port and only leaves
one port (unless it is broadcast, or completely filtered out.)  The next
packet to enter, may be forwarded to a different port based on destination
address...

>No need for Carrier Sense, there would be no Multiple Access, and
>you would not need to Detect Collisions...= not 802.3 CSMA/CD!  And

Unless of course you have multiple devices at one end of the tp.  (IE a
repeater from tp to thin net.)

>how would you support multiple hosts?  Link them via SONET/FDDI and
>'telnet' through your 'local' host.

The same way you do now.  What's the problem?

>>  The closest I've seen done is to have many small hubs,
>>and bridge each of the hubs into a central hub.
>
>...and you had better have a server on each hub or else you suffer the
>fate of the forwarding rate...

Not if your bridge has a decent forwarding rate.  Have *you* actually tried
it?  The performance is better than having the servers compete with 500 computers
for the same bandwidth.  On the average it filters out more and reduces the number
of collisions so that the overall speed is much greater.