Architecture and topology of 3COM SuperStack II 3900 switch?

Eray Ozkural (exa) erayo at
Mon Jul 23 21:02:17 PDT 2001

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On Tuesday 24 July 2001 06:24 am, you wrote:
> On Tue, Jul 24, 2001 at 04:52:20AM +0300, Eray Ozkural wrote:
> > Recently I've stumbled into a problem due to our lack of
> > knowledge about the 3COM 3900 36 port 100Base-TX switch with gigabit
> > uplink. I need to know the architecture and topology of the
> > interconnection network within the switch in order to implement the
> > optimal parallel algorithms in the code.
> It's probably a flat topology. That will make your life a lot easier
> when it comes to optimal algorithms.

In our measurements we observed good connectivity, but I'd need precise 
information. By flat topology, do you mean a K_{32} clique? This would mean 
that there can be C(32, 2) concurrent communications each of which can carry 
100MBit (ie in case of all to all broadcast) which does not seem likely to 
me, but of course if that little box is capable of that I'd be optimally 
glad. I've seen remarks of a "backplane" limited by a bandwidth which was not 
particularly high on this list but if that refers to a bus which interfaces a 
dynamic network it would complicate my matters. On the other hand, it would 
be good to know the bisection bandwidth of the interconnection network but 
I'd be more satisfied if I could learn the exact architecture of the network: 
what kind of switches there are, in what way they have been connected and how 
messages are routed.

Other people have simply assumed that it was a mesh or a hypercube. I decided 
to inquire the nature of thisbeowulf at black box because I don't 
like to play dice. In addition to this, other researchers have been asking me 
the topology of the network and I cannot quite answer.

In the algorithm we are developing, we need to know the connectivity of the 
network otherwise we might end up with taking more steps than necessary.

Thanks for your attention,


- -- 
Eray Ozkural (exa) <erayo at>
Comp. Sci. Dept., Bilkent University, Ankara
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