[OLPC Networking] Re: [olpc-software] "Mesh" Software

[Jim Gettys]

On Mon, 2006-04-17 at 22:00 +0200, Fabian Deutsch wrote:
> Hey,
> 
> I just looked through the archives but didn't find anything about the
> software, which is going to be used to create the wireless-mesh.
> 
> Maybe 802.11s would have been a good start, but doesn't seem to be ready yet

I believe Michail Bletsas is planning to use the drafts as a starting
point for what he's doing in that area.  But as you say, it isn't a
standard yet, so the best we can do is an approximation, and get to
discover problems with the proposals in advance.
> ...
> 
> There are protocols like AODV and OLSR, but I'd personally prefer something
> more standard. Something like OSPF.
> 
> OSPF isn't suitable for wireless meshes currently, but there are some
> efforts to extend OSPF v3 [1] in a way, so it can be used in MANETs.

IIRC, Michail says there are 3 routing protocols in existence used in
meshes; we do not know yet which will be most interesting in which
circumstances.  I don't know if any of them resemble OSPF.  Which is
most useful in what circumstances will require more serious
experimentation.  

The fundamental difference between what we are doing and, say, MIT
roofnet, is that the nodes are much more mobile than in a fixed system.

A second topic, which is probably worth one or more PHD thesis, is for
the mesh to be power aware.

For example, you would probably not want all nodes forwarding all the
time, if you don't need to, and would want to elect nodes that have
power preferentially from those that are on battery.  And for those not
actively forwarding, you'd prefer to keep the radios off for most of the
time.

The Marvell wireless chip selected has enough smarts that such behavior
could (if one is careful about space use), be done without the main
CPU's intervention, by having the processor in the Marvell chip turn on
the radio periodically and see if it should participate.

> 
> ANother interesting document can be found here [4], which gives some
> informations about the behaviour of MANETs with about 100 nodes.
> 
> There is already a patch (draft)[2] for quagga[3] and a simulator 2]
> available.
> 
> fabian
> 
> --
> [1] http://www.ietf.org/internet-drafts/draft-ogier-ospf-mdr-position-00.txt
> [2] http://hipserver.mct.phantomworks.org/ietf/ospf/
> [3] http://www.quagga.net/
> [4]
> http://hipserver.mct.phantomworks.org/ietf/ospf/reports/Boeing-D950-10897-1.pdf
> 

Thanks for the pointers.

                                Regards,
                                     - Jim

-- 
Jim Gettys
One Laptop Per Child