[Babel-users] a new way to mesh in openwrt

[Benjamin Henrion]

Le mer. 30 oct. 2024, 12:26, Juliusz Chroboczek <jch at irif.fr> a écrit :

> Hi Donald!
>
> >> It never worked well beyond a few nodes, since it requires global
> >> synchronisation (of beacons?  I forget) across the whole mesh.  I could
> be
> >> wrong, but I believe tha 802.11s doesn't have that flaw.
>
> > I think the main problem with ad-hoc mode is that all the stations
> > need to be able to see each other's transmissions. 802.11s is
> > multi-hop and does not have that problem. Ad-hoc mode was just for
> > something like a modest number of people with laptops sitting around a
> > table or the like.
>
> I think Benjamin was assuming that there is a routing protocol running
> over the ad-hoc mesh.  In MANET terms, 802.11 in ad-hoc mode is the
> underlay, and a proper layer 3 routing protocol (such as OLSR-ETX, Babel
> or BMX6) is the overlay.
>
> However, it turns out that doesn't work very well in practice, the
> underlay tends to get partitioned due to synchronisation issues.  So
> people have been running their underlays in infra mode, which causes a lot
> of extra complexity, since you need to manually choose the gender of every
> router.
>
> 802.11s routing doesn't scale, but people have been experimenting with
> using a degenerate form of 802.11s as the underlay with Babel as the
> overlay.  I haven't tried it myself, but I've heard that it doesn't work
> very well due to buggy firmware in off-the-shelf routers.
>
> If I understand the blog posting correctly, with APuP, the Freifunk guys
> are trying to use infra mode, which is well supported by off-the-shelf
> routers, but simplify the administration by allowing APs to mesh with each
> other using the 4-address (WDS) frame format.  Which is pretty cool if it
> turns out to work at scale.
>

I am wondering if it could run on top of hwsim:

https://www.kernel.org/doc/html/latest/networking/mac80211_hwsim/mac80211_hwsim.html

Because to simulate a large network you need to have a simulator, or an
actual large network to test it on.


> -- Juliusz
>
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