Turns out there have been some works-fine, moderately-priced fiber-optic cables for DisplayPort for a while now. A DisplayPort 32Gbps cable can be gotten for <$50, and unlike copper, the length doesn't really affect the price that much: fiber is bloody cheap. And so pleasantly light weight to deal with!
I've used this for sitting on my porch & doing gaming. I probably have enough usb2 cable to make it up the roof but haven't tried it yet.
But I could very much see something like what Rockport is doing being based on this tech. As opposed to trying to stuff some 400Gbps ultra-powerful nics into a box, & run them to a switch, it makes all the sense in the world to have an array of cheaper-to-make, cheap-fiber, cheap-xmitter 25Gbps connections coming out of a box, and to esckew central switching entirely. They might potentially even use the same low-cost xmitters my cheap cables use! I'm pretty stunned by the effort here- if I read this right they're doing 12 ports per box, which is a very high radix connectivity. That could allow some truly fascinating topologies to be created.
I'm kind of under the impression that these fiber optic hubs create a pretty narrow set of topologies, that this is kind of following a top-of-rack-ish model, but I haven't investigated much to understand deeply what Rockport is offering. But I've been thinking about these cheap cables, wanting to see more consumerization, more fiber optics, and this definitely seems like a potentially very interesting disruption from below.
Only this time all the logic is on the network card, and the connector has 12 separate optical fibers. And the “switch box” is fully passive, just shuffling the connections from different machines around.
This is obviously very expensive, and so that’s private why it is marketed to HPC people.
