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<p>Hallo Mark,</p>
<p><br></p>
<p>Mittwoch, 25. Juni 2008, meintest Du:</p>
<p><br></p>
<p><span class=rvts6>>>> so the switch fabric would be a 'leaf' layer with 12 up and</span></p>
<p><span class=rvts6>>>> 12 down, and a top layer with 24 down, right? so 3000 nodes</span></p>
<p><span class=rvts6>>>> means 250 leaves and 125 tops, 9000 total ports so 4500 cables.</span></p>
<p><br></p>
<p><span class=rvts7>>> The number of switch layers, or tiers, depends on the cluster size and</span></p>
<p><span class=rvts7>>> the oversubscription. For full non blocking, 2 layer of 24 switches get</span></p>
<p><span class=rvts7>>> you up to 288 ports switch, and with 36 ports up to 648 ports.</span></p>
<p><br></p>
<p><span class=rvts6>MH> I guess I'm confused. wouldn't a non-blocking fabric with 288 host ports</span></p>
<p><span class=rvts6>MH> be one layer of 24x 24pt switches (12 up, 12 down to hosts), with _half_</span></p>
<p><span class=rvts6>MH> as many top-level switches (ie, 12 switches with 24 down each)?</span></p>
<p><br></p>
<p>That is how it is build normally.</p>
<p><br></p>
<p>Regards,</p>
<p>Jan</p>
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