a yet another stupid network topology

[Yoon Jae Ho]

I think that if you want to use small port Switches, how about consider the "Loki"

http://loki-www.lanl.gov/loki-image.jpg

which explain in the  http://loki-www.lanl.gov/loki-inside.html
 
or,

how about creating the FNN Designs 

http://aggregate.org/FNN/

for the small beowulf (lesser than 5 nodes) ,  

Instead using the solution before (4 NICs/node, projection from above, S: switch, N: 
 node; single elementary cell shown)  
 
   |   |
  -N   N-
    \ /
     S
    / \
  -N   N-
 
how about using  below solution 4 port Nic/node with no switch for economic reason. 

    |
  -N   N-
     \ /
     / \
  -N   N-
 
--------------------------------------------------------------------------------------------------------
Yoon Jae Ho
Economist.
Seoul, Korea
3457-8228
 
yoon at bh.kyungpook.ac.kr
 
Imagination is more important than knowledge.  A. Einstein
--------------------------------------------------------------------------------------------------------

----- Original Message ----- 
From: Eugene Leitl <eugene.leitl at lrz.uni-muenchen.de>
To: <beowulf at beowulf.org>
Cc: <eugene.leitl at lrz.uni-muenchen.de>
Sent: Monday, October 30, 2000 10:58 PM
Subject: a yet another stupid network topology


> 
> I've been thinking about network topologies for physical simulations
> (spatially distributed over nodes, only locally coupled). The
> assumption is that few-port FastEthernet switches are much less
> expensive per port and typically have a larger backbone bandwidth then
> larger switches. Is this still correct?
> 
> The solution before (4 NICs/node, projection from above, S: switch, N: 
> node; single elementary cell shown):
> 
>   |   |
>  -N   N-
>    \ /
>     S
>    / \
>  -N   N-
>   |   |
> 
> This one is scalable, but it is rarely possible (due to simple budget
> reasons) to go beyond 64 nodes, or so. Hence: the next stupid idea: we
> have only 64 nodes, 3 NICs/node and 12 16-port
> switches. (alternatively, same number of nodes, 4 NICs/node and 16
> 16-port switches). View the nodes as arranged on a 4x4x4 cubic
> lattice. Think the switches arranged thusly (projection from above):
> 
> N N N N
>    S
> N N N N
>  S   S
> N N N N
>    S
> N N N N
> 
> We use each 16-port switch to crosslink the individual 2x2x2 cubes
> along the larger cube axis. (In the larger 16 switch solution,
> switches also crosslink the 2x2x2 cubes along the larger cube axis).
> 
> For all this to make sense, we need
> 
> 1) 16-port switches are much cheaper/port than 32-port switches and
>    larger 
> 
> 2) above cheap 16-port switches can provide full 200 MBps*16 backbone 
>    bandwidth
> 
> 3) we can feed 3 (or even 4) FastEthernet NICs in a node
> 
> If each of the switches have 1 GBps uplink port, we obviously can
> connect the whole system to a user pool without apparent bottleneks.
> 
> I would welcome any comments on this scheme. (yea, nay, wtf, etc.).
> 
> TIA,
> 
> -- Eugene Leitl
> 
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