Author Topic: USB 3.0/2.0 Hubs & aggregation of 2 USB 2.0 480Mb signals into 1 USB 3.0 5Gb sig  (Read 5967 times)

st2000

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Hi,

I have 2 USB 2.0 video sources that are creating loads of data.  So much that if I aggregate the 2 signals I will exceed the USB 2.0 speed limit.  So I started looking for USB 3.0/2.0 hubs that could aggregate 2 USB 2.0 signals into 1 USB 3.0 signal.  So far all the hubs I have looked at appear no not have this feature.  Instead what starts out as USB 2.0 on the DEVICE (PERIPHERAL) side of the hub remains on the USB 2.0 line on the HOST side of the hub.  Perhaps this "aggregation feature" is impossible by design or by definition.  Or, perhaps I have not yet found the USB hub that does this.  Any help would be appreciated.

-thanks

Jan Axelson

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USB 3.0 hubs don't upgrade incoming USB 2.0 traffic to SuperSpeed.

If the PC has multiple USB 2.0 host controllers, one way to get more bandwidth is to attach each source to a different host controller. (View host controllers in Windows Device Manager).




st2000

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Quote
one way to get more bandwidth is to attach each source to a different host controller
Thought so.  Problem is, the embedded Linux board I am using only has (AFAIK) 1 host controller for the 2 USB 2.0 Standard Type A sockets.  This is assuming that a single USB 2.0 host controller can only handle a total of 480Mb of data.  Is that (always) true?

-thanks

Jan Axelson

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If the host-controller driver and device support high-bandwith endpoints (multiple transactions/microframe), the theoretical maximum data throughput per high-speed isochronous endpoint is 24.576 MBytes/sec.

On a high-speed bus, interrupt and isoc. transfers should use no more than 80% of a microframe. (The host-controller driver might enforce this.)