QSFP+ NIC to Cisco SFP switch

applesapplesapples

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Oct 9, 2021
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I recently picked up a server with a two ConnectX®-3 Ethernet Single and Dual QSFP+ Port Adapter Cards installed and was given two Cisco Catalyst 3560CG-8PC-S Compact Switches as well and was wondering if it's possible to get the connection from the server's QSFP+ port to the SFP port on the Cisco switch. I am not very familiar with SFP networking but based reading some other posts (Using a 40GbE (QSFP+) NIC with a 10GbE Switch (SFP+)) it seems like it may be possible? I was looking at getting a 40G QSFP+ to 10G SFP+ converter module and using an SFP+ cable to the Cisco switch but since it's only an SFP port on the switch I'm not sure that the SFP+ cable work and just use the slower SFP speed?

Any help or direction would be very appreciated!
 

klui

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Feb 3, 2019
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I've never tried but Linux says CX3s support 1G.

You will not be able to connect the dense end of a breakout to older cards like what the OP has and use one lane. You can only use a QSFP to SFP adapter.
 

fohdeesha

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applesapplesapples

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Oct 9, 2021
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Thanks everyone. @fohdeesha would that adapter be ok for QSFP+ port on the cards?

Also, any recommendations for a reasonable QSFP+ switch? I was thinking of throwing the other QSFP+ card in another computer to link the two. Can the be linked directly without a switch?
 

fohdeesha

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Thanks everyone. @fohdeesha would that adapter be ok for QSFP+ port on the cards?

Also, any recommendations for a reasonable QSFP+ switch? I was thinking of throwing the other QSFP+ card in another computer to link the two. Can the be linked directly without a switch?
yes that adapter would work in the cards. or like you said you could go directly between two PCs with a qsfp DAC, that would work no problem