> Aggregation spine? Can you tell me more about that? Can you give me a > part/model number?
spine is just the term for the trunk of a fat tree. usually the per-rack switches are called leaves since if nothing else, they may not be at the top of the rack, or there may be more than one per rack... the good thing about the leaf/spine approach is that it's modular, and possibly less vendor-locked-in. (not that IB is really multi-vendor anyway). cable-wise, I'm not sure leaf-spine really wins, since you can think of a chassis switch as a leaf-spine with FR4 rather than CX4. AFAIKT, the same radix-36 switch is used in each. spine/leave can be distributed so that there's no one place where you get too many cables. "less than fully fat" fabrics seem to be pretty common when taking the modular approach. for instance, if a 36x switch is split into 24 down (node) and 12 up, you can put two back-to-back, or have three going into a single spine switch, or more going into multiple spines. you could even have some racks with more spineward links. and in your case, you could vary the number of links going to your existing chassis switch (though it probably shouldn't be the spine since all its links are slower...) -mark _______________________________________________ Beowulf mailing list, [email protected] sponsored by Penguin Computing To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
