Re: SV: [ECOS] Gigabit Ethernet throughput on XScale

[Andrew Lunn <andrew at lunn dot ch>]

On Tue, Jan 13, 2004 at 09:58:28AM +0100, Lars.I.Nilsson@tietoenator.com wrote:

> The reason I whant to use gigabit Ethernet is that there will be
> several cameras connected to the same network. With a total bandwith
> of approximately 200 Mbit. If it was just one camera, 100 Mbit would
> be sufficient.

Ethernet is no longer a shared medium with CSMA/CD like it used to
be. So in fact you want an Ethernet switch which has several 100MBit
ports for your cameras and one gigabit Ethernet for the link to where
ever the data is heading.
 
> If you look at 100 Mbit Ethernet. Is it realistic to have a
> throughput of 20 Mbit from one camera, on an XScale PXA250 400
> MHz. The video encoding is not handled by the Xscale processor, its
> done in separate hardware.

It sounds reasonable, but it will depend on a number of things eg the
the choice of Ethernet chip, the size of the packets you send, the
available CPU bandwidth, etc. 

I would ask around and see if anybody else has a similar setup and see
what performance they get.

     Andrew

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