One instance of this was the parallel universe of FireWire hubs. In case you consider FireWire as “a giant USB” then a hub wouldn’t appear so unusual, however FireWire was really meant to interchange SCSI. SCSI and FireWire are peer-to-peer: any system on the bus can speak to another system, in contrast to USB the place every bus has at most one host and the host does all of the initiation of information switch. (USB On-The-Go nonetheless has one host and one host solely; it simply permits sure units like your cell phone to swing each methods.) The purpose-to-point capabilities of USB 3 however, a USB hub has one upstream port for the host and a number of downstream ports for the units. A FireWire hub, nevertheless, is like getting an extended inside SCSI cable; extra units merely exist on the identical bus. Connecting a number of FireWire hubs simply makes a much bigger bus as a result of all of the ports are the identical.
Every thing you ever needed to learn about FireWire hubs, with numerous examples.