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

[aosudh]

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.


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.
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 .





So, how can I get this type of cable or optical transceiver?

 

[klui]

This link shows cables that are compatible.

ConnectX-7 Cables - Included Content - NVIDIA Networking Docs

docs.nvidia.com

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]

This link shows cables that are compatible.

ConnectX-7 Cables - Included Content - NVIDIA Networking Docs

docs.nvidia.com

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]

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]

any update on your trials?

 

[aosudh]

any update on your trials?

 

[aosudh]

any update on your trials?

Then I will try to purchase some 16 lines fiber cables and connect two of them to see if it can work

 

[jpmomo]

the dac cables that I was referring to with the "flat top" on both sides: