When is my usb hub a smart hub?
What is a usb smart hub?
What is a usb smart hub?
Cynically it's a hub that hasn't has its functionality impaired by cost-optimisation.
Technically it's a hub that implements per-port power control and optionally per-port over-current detection.
An example is the old Linksys USB2HUB4 hub that's nearly 20 years old but still reaches decent bids on eBay as it is sought after by many hobbyists. It uses the excellent NEC PD720110 chipset that doesn't cut any corners. It even boosts USB1.1 comms up to USB2.0 speed over the host link.
The terminology to look for is "multi-TT" (transaction translator) for this feature. Very useful for hooking up a whole bunch of serial ports to an embedded controller over USB. I made a video about doing so for my old startup like 7 or 8 years ago (though the hub in the video may have been single-TT... It was stolen so I can't go back and test it again).
Per-port power and LED control was also really useful, but really rare, for embedded hardware. The idea was that a ton of peripherals would be connected over a network of USB extenders, and a user interface would let you flash the LED next to a device you wanted to find, if you weren't sure where it was. No cloud needed.
sudo lsusb -v | grep wHubCharacteristic -A 3