On Mon, 08 Apr 2013 21:26:58 +0100 Wayne Stallwood ALUGlist@digimatic.co.uk allegedly wrote:
On 08/04/13 20:32, mick wrote:
I am considering options for building a very small, low powered in-line F/W and some of the devices I am looking at only have one ethernet port (but often two or more USB ports).
I'm not sure about the potential bandwidth you'll likely achieve but what I will say is that USB interfaces and devices are CPU bound..so CPU usage will grow with network traffic faster than it would if you had a "real" NIC.
On a modern PC it isn't so much that you'd notice...on a small embedded system such as you may be using for this project it will become a factor, particularly if more than one interface is in use.
Also watch out because some (and one very popular *cough*) low power embedded systems already have their internal NIC hanging off a USB interface...the bandwidth isn't per port it's per controller bus, of which anything small and low power is only likely to have one.
Wayne
Thanks for the input (and thanks also to BJ).
The device I am currently playing with is a sheevaplug. Not fantastically fast, but a lot faster than my NSLU2s and the pi. I haven't yet tested it in anger because I'm still building the thing (probably shorewall).
The generic chinese 10/100 USB adaptor I bought (my network runs at 100Mbits/s) *just works* when plugged in to the sheevaplug (running debian squeeze.) It runs noticeably very hot - not sure if that is normal.
Cheers
Mick ---------------------------------------------------------------------
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