Building exchanges that matter ..

Joe Rhett joe at Navigist.Com
Sun Dec 8 10:53:11 UTC 1996

> Very fast ethernets are designed with two modes, standard
> a standard CSMA/CD bus and a full-duplex collision-free mode.
	[ .. your lesson on basic networking deleted .. ] 
> ATM since one is stuck playing with forwarding based on
> only one address space.
Yah, I'm familiar with all this. I'm sitting behind one of those
"Bad Notworks" boxes right now, actually.

> I'm not sure what flexibility you're referring to wrt ATM
> vs very fast ethernets, however the latter in combination
> with software in one particular modern router that isn't
> completely rocket-science can spoof rate-limited VCs
> based on MAC addresses, which more-or-less duplicates
> the one feature of ATM that I happen to like.
Uh.. I'm not sure what you're asking, because I suspect the answer 
I'm about to give you'd have already considered, no?

Ethernet -> Flat. Creating true architectural redundancy isn't possible
without separate routes for each connection. Also, even full duplex
Ethernet never achieves full bandwidth utilization due to the protocol
implementation (hardware protocol).

Advantage: All vendors support it, and is usually works without help.

ATM -> Flat/Star/Web/whatever. You can create both bandwidth and
redundancy without routing. 

Disadvantage: Every vendor supports it differently, and most of them
only have 2 people that really know it. Never works without help.
Also, congestion control between hetrogenous systems is a no-op.

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