The switch is not like those you might typically find in AI clusters in that the actual switching is handled entirely optically, rather than using transceivers to convert photons into electrons and back again. Laser light simply enters one port and exits another – with a little bit of attenuation, of course., which is slated to ship in volume next year, features 300 input and 300 output ports and is based on Coherent's Datacenter Light Wave Cross Connect tech.
Additionally, Coherent notes that this kind of optical switching tends to be more reliable – something that will pay dividends in very larger clusters in which mean time to failure tends to be quite low. Swing explained this approach has a couple of benefits – including the ability to reconfigure the cluster size dynamically. Another is that all of the accelerators are connected to one another, which improves reliability – a desirable quality as training workloads can last months depending on the model's parameter count and the size of the dataset.