[Beowulf] How to configure a cluster network

[Kilian CAVALOTTI]

On Thursday 24 July 2008 05:42:22 am andrew holway wrote:
> To give a half bisectional bandwidth the best approach is to set up
> two as core switches and the other 4 as edge switches.
>
> Each edge switch will have four connections to each core switch
> leaving 16 node connections on each edge switch.
>
> Should provide a 64 port network.

I'm also curious to know if there's a general formula to determine the 
required number of IB swicthes (given their ports count) to create a 
full (or half) bisectional network capable of interconnecting say N 
leaf nodes, and especially, if there's a way to deterministically infer 
the manner to (inter)connect them.

I've seen numerous examples involving small amounts of nodes and 
swicthes, but I can't figure a way to scale those examples to larger 
networks.

Any pointers?

Thanks,
-- 
Kilian