Memes

That's because I asked it to explain the technical aspect of the question, not answer it.

Here's the answer it gave me when I asked it to answer the question:

Yes, I can provide an answer to the technical question in the photo.

The question is: "Can I attach a 10GBase-LR to QSFP-40G-LR4 (CWDM)?"

Answer: In general, you can't directly connect a 10GBase-LR transceiver to a QSFP-40G-LR4 transceiver because they operate at different data rates (10 Gbps vs. 40 Gbps). Additionally, the QSFP-40G-LR4 typically uses four separate lanes of 10 Gbps each, which is why it has the "4" in its name.

However, there are solutions to bridge these differences:

1. Breakout Cables: You can use a 40G QSFP+ to 4x 10G SFP+ breakout cable. This cable will split the 40G signal from the QSFP-40G-LR4 into four separate 10G channels. You can then connect one of the 10G channels to your 10GBase-LR module. This will only utilize 10 Gbps of the 40 Gbps available from the QSFP+ port, leaving the other three channels unused.

2. Transponder or Media Converter: These devices can convert signals between different data rates. A transponder could take in the 10G signal from the 10GBase-LR and output it as one lane of a 40G signal compatible with the QSFP-40G-LR4. However, similar to the breakout cable, this will only utilize a fraction of the 40G capability.

3. Switch/Router Configuration: Some high-end networking equipment allows you to configure the data rate of specific ports. If both transceivers are plugged into such a device, you could potentially configure the QSFP-40G-LR4 port to operate at 10G, but this would be vendor and model specific.

Regarding the CWDM component, if both transceivers support CWDM and are operating on compatible wavelengths, they should be able to communicate over a CWDM system. However, CWDM is typically used to combine multiple signals onto a single fiber, so if you're just trying to connect these two transceivers, the CWDM component may not be necessary unless it's part of a larger network design.

Always consult with the documentation of your networking equipment and, if possible, conduct tests in a lab environment before making any changes to a live network.

Seems to work mostly fine: https://community.fs.com/blog/40g-qsfp-to-10g-sfp-configuration-guide.html

Considerations for QSFP+ to SFP+ Split

Usually, this split configuration is supported on most switches provided by different vendors regardless of standalone and stacked ones. Certainly, you still need to check this function in the instruction of your switch or consult your vendor, as it’s the most basic condition of splitting QSFP+ to SFP+ configuration. Sometimes, most ports on a switch support split, but some don’t. In other cases, when a switch is deployed as a leaf switch, some ports do not support the split. Or when the port is already used as a stack port, this may also limit split configuration. Thus the conditions can be quite different based on your applications.

Also for whoever is curious, there’s 100G QSFP28 which has breakdown cables to 4x 25G SFP28, I’m not a networks guy but I think at that point it’s not Ethernet anymore but InfiniBand.