About the non-standard OSFP cage in mellanox Connectx-7 400G Network Adaptor

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aosudh

Member
Jan 25, 2023
46
15
8
I recently got some connectx-7 from local distributer that used to sell unlisted lab equipment from some of the big companyies. As the price was fair enough, i just immediately purchased it without further testing and evalutation. 0828EA970BE1D50A96BE54FE0E3DC084.jpg
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Unfortunately, when I tried to connect two of the NICs , I found that none of the standard QSFP-DD and OSFP cables includng AOC ,DAC and active DAC can fit well with the cages in this CX7 NIC which mellanox called it "OSFP".So I read the OSFP specificatoin and the size is below.1674891499938.jpeg
When comparing to the standard size, it seems that mellanox has created a new type of OSFP by removing the cooling fin above the transceiver in order to make their NICs more flexible as the width of standard OSFP transceiver is a bit wider than a single pcie slot when considering the thickness of PCB and the fin of the cages .
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So, how can I get this type of cable or optical transceiver?o_Oo_Oo_Oo_Oo_O
 

klui

Well-Known Member
Feb 3, 2019
824
453
63
This link shows cables that are compatible.


Looks like early adopters get to play cable musical chairs because there were a lot of changes these past 2 years. Many Nvidia OSFP cables EOLed in late 2021 and that's when Nvidia announced CX7s! Here's one example: https://network.nvidia.com/related-docs/eol/LCR-000858.pdf

I think these cards are meant to support their Quantum-2 platform. Current datasheet at infiniband-ndr-400g-architecture-datasheet-1620877-r4.pdf
 

aosudh

Member
Jan 25, 2023
46
15
8
This link shows cables that are compatible.


Looks like early adopters get to play cable musical chairs because there were a lot of changes these past 2 years. Many Nvidia OSFP cables EOLed in late 2021 and that's when Nvidia announced CX7s! Here's one example: https://network.nvidia.com/related-docs/eol/LCR-000858.pdf

I think these cards are meant to support their Quantum-2 platform. Current datasheet at infiniband-ndr-400g-architecture-datasheet-1620877-r4.pdf
The original cable is hard to get and quite expensive compared to the price of the card.:(
And there aren't any differences mentioned in the document about the NVIDA's OSFP and standard OSFP. Maybe this type of card is already EOLed and switched to QSFP-DD cages as some of my friends worked in server company have sought comfirmation about those OLD NICs .
I would try to remove the original cages and place a standard cage to test it with some cheap and standard OSFP DACs.;)
 

jpmomo

Active Member
Aug 12, 2018
531
192
43
You will need an OSFP800 DAC flat. It will use 4 of the 8 100G electrical lanes. The flat references the lack of a heatsink on the cable. The cage on the nic will provide the heatsink.
Sent you a pm if you want to discuss in more detail.
 

jpmomo

Active Member
Aug 12, 2018
531
192
43
the dac cables that I was referring to with the "flat top" on both sides:

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