[mesh-dev] meshing/bridging and babel

[Dave Taht]

I am not normally on this list, but for some reason a search turned it
up this morning.

I run a babel-based mesh network down in los gatos and perhaps I have
an insight or two to help.

0) Bridging over wifi sucks, particularly when mdns or other multicast
traffic is present. It takes very little multicast to mess up your
whole day

1) Distributing ipv4 addresses and prefixes is a pita. The new hnetd
protocol intends to try and make that more automagic, but it has a
desire to be god-like over everything and every daemon. Still, more
eyeballs on it and perhaps it could be made to work.

See: http://www.homewrt.org/doku.php?id=overview

DNS is a pita, also. - some hope for mdns-proxy...

1.5) I used to use AHCP for interconnecting mesh nodes, which worked
quite well, particularly for ipv6. It did not distribute prefixes,
however, which led to (the thus far abortive) hnetd.

2) Babel's diversity algorithm seems to be suffering from an old
system call which only works in adhoc mode, not AP mode. It also
contains some bridge disambiguation logic (but failing to get the
channel right in that case does not help). It does sort of do the
right thing, even not getting the right info, shipping "interfereing"
around... and it looks like short work to get it to get the right
channel automatically given example code in the iw utility and olsrv2
- but I lack the time, personally, to do that right now.

Relevant thread and pointers here:
http://lists.alioth.debian.org/pipermail/babel-users/2015-June/002056.html

3) openwrt, at least, has moved away from dnsmasq being the dhcp
server in favor of their own server implementation. In neither case
does dhcp handle ptp /32s, so you need another address distribution
mechanism for this anyway.

Given the headaches in doing this automagically I lean towards static
assignment for ipv4.

4) babeld-1.6.0 had a bug in source specific routing, now fixed in
babeld-1.6.1. At the moment I am exploring various facets of that to
leverage building up the prefix distribution scheme.


-- 
Dave Täht
worldwide bufferbloat report:
http://www.dslreports.com/speedtest/results/bufferbloat
And:
What will it take to vastly improve wifi for everyone?
https://plus.google.com/u/0/explore/makewififast