Hi Jason, Good to hear you have some experience with them.
> >> * Anybody has experience using QSFP+ and 40G switch with ROACH2 or in other >> settings? > I've played with these "octopus" cables on Arista switches with ROACH-2s, and > will be fiddling with Mellanox, Cisco, Alcatel-Lucent and Extreme switches > too, soon. I don't foresee any problems. If you do this, the QSFP+ port > usually appears on the switch as four independent 10GbE ports. > > I didn't find that the cabling was significantly different... they're still > passive and so costs are similar. And if your boards are all in a rack, then > it's actually quite neat. If you've got them in different places, then the > breakout cables are definitely awkward. Plus, it's nice to have future 40GbE > capability. > The cabling is what worries me, especially I need to run "long" optical cables in some of my experiment (6 floors up). So I'm not very sure about how the octopus cables would work there. Of course, I can also just aggregate the data first at the switch and run 40G ethernet through fiber. Have you happened to have played with optical version of such cables? >> * What do you feel about the prospect of 40G with QSFP+ in the near future? > > We're not doing QSFP+ on ROACH2, mainly because we can't find suitable PHYs. > So you'll need to wait for ROACH3 (next year?) for native 40GbE. > Will be interesting to see. --Hayden
