New to the forum — this might be a simple question, but I couldn’t find a clear answer in the documentation so far. Thanks in advance for your help.
If I connect two SN5600 switches for ICL or MLAG over an 800G port using an 800G DAC or ACC cable, do I need to break out the port as 2×400G (e.g., swpxs0 and swpxs1) for the link to work, or can it operate as a single 1×800G port (swpx) as supported by the switch?
The reason I ask is that both the DAC (MCP4Y10) and the ACC (MCA4J80) show in their specifications as twin-port OSFP / 2×400 Gb/s data rate. This makes me think the port might need to be broken out into 2×400G to use the cable properly.
Also, when using optical transceivers such as MMA4Z00-NS or MMS4X00-NM, I understand the port does need to be broken out into 2×400G, since those transceivers physically connect via two ports/two fibers within a single module.
Could someone please confirm if this understanding is correct?
DAC/AOC cables support up to 800Gb/s but are listed as twin-port 2x400Gb/s due to the dual 400Gb/s internals that combine to make 800Gb/s. For the DAC/AOC models you listed, please contact your Nvidia sales rep to confirm they will work for your application. I see some references to IB-only operation and IB/Eth operation.
The MMA4Z00-NS or MMS4X00-NM modules can bundle the twin ports together for a 1x800Gb/s link, but typically we will break it out into 2x400Gb/s for easier deployment & maintenance. The 1x800Gb/s would require both fibers to be in good working condition before the link will come up, which makes troubleshooting L1 issues problematic.
I would add even if it is DAC/AOC one single physical link between the two end attached tranceivers, I would still like to go as 2x400G config, as this will add more flexiability for future if the design changed need to use transceivers + two fibers or use breakout cable connect with two devices the other end.
For SN5600, when you use 800G DAC (MCP4Y10) or 800G ACC (MCA4J80), the port can run directly as a single 1×800G interface. Even though the specs describe them as twin-port OSFP / 2×400G, that’s just the internal electrical structure of the cable. From the switch side, they behave as a native 800G link, so no breakout is needed for ICL or MLAG.
For optical modules like MMA4Z00-NS or MMS4X00-NM, your understanding is correct. Those modules expose two separate 400G optical interfaces inside one OSFP, so the switch port does need to be broken out into 2×400G for the link to work.
Hi all, we are in deployment stage and have chance to test both 800G DAC (MCP4Y10) and optical transceivers MMA4Z00-NS in our project. Just to give you all update on this topic for contribution, if anyone interest in it.
We can confirm both DAC and transceiver they can work either as one single 800G mode or 2X400G mode. This has been tested between SN5600 pairs.
In our deployment, we use 2X400G mode for the 800G DAC even though it can work as single 800G mode, the reason is if we have one separate cable media break internally for any reason, we will still have another 400G work between the two switch ports. If set the cable as single 800G mode, an internal separate link down will bring down the whole 800G connection.
Hope this can help someone in future if have same confusion on this topic.