Gabor, Our main design constraint when we were planning the mesh implementation was power consumption. For a laptop mesh to be dense enough, it is imperative that the user doesn't worry about battery consumption when the laptop does nothing else but forward traffic for other users. Existing laptops require something around 10W to forward packets wirelessly. Our laptop can do it with ~3W using the GX2 and a conventional laptop WiFi card, however given that we only have a ~25Wh battery, that was still to high for our goal.
Thus, we had to utilize an embedded WiFi module with its own CPU and memory and Marvell's 88W8388 was pretty much the only choice. To give you an idea of the power savings, we can forward frames with less than 400mW allowing for our NiMH battery to keep a laptop running as a wireless router for 2 days. 802.11s helps keep functional separation between the GX2 and the ARM core on the Marvell chip since it operates on layer 2. So frames are handled by the 8388 and packets by the GX2 (we are not running the TCP/IP stack on the 8388). This has created some confusion because 802.11s does ad-hoc routing using MAC (layer-2) address, however that routing is transparent to layer-3. Marvell already had a full network stack running on the 8388 so they only had to add the 802.11s layer to it (they are paying the people who do that development) and that's what they are going to release. with the intention for that code to become a module for d80211. There is a bigger question as to whether it is practical to expect complete open source firmware on the 8388 and my take on that is that it is, however it will take time that extends well beyond OLPC's deadlines. Best, M. "Gabor Dolla" <[EMAIL PROTECTED]> 12/31/2006 11:25 AM To "Michail Bletsas" <[EMAIL PROTECTED]> cc [email protected], [EMAIL PROTECTED], [EMAIL PROTECTED], "Rob Savoye" <[EMAIL PROTECTED]> Subject Re: OLPC Laptop - an open source substandard ? Hi end of February. In parallel we are working with Marvell to release the 802.11s source code under GPL. Who is going to ravel out the 802.11s code from the tangled source ? I'd help if needed.. What I can not see is how the Linux running on the main CPU and the Marvell chip with its own OS and ip stack work together ? Usually the main OS handles the routing, ARP, etc... If the Marvell chip does the routing what the Linux does ? Happy New Year to you, too Gabor
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