[Babel-users] Multiple internet gateways in the mesh

[Mark Shuttleworth]

Hi folks

I run a mesh across three sites each of which has their own internet 
connection, but they are of different capacities.

Babel does a great job of keeping the three sites talking to one 
another. But I am unable to get the default route behaviour that I would 
like. I would like to use the fastest internet connection that is 
available for the whole mesh. If I can get all traffic going out of the 
fastest internet connection, that would be great, and if not I'd like 
the mesh to fall back to the second fastest, and finally third fastest 
connection.

I have a hack which pings from each site to see if its own internet 
connection is up. If it is, it installs a default route. The metric of 
the installed route reflects the speed of the connection. If its own 
link is down, it removes any default route, so that Babel will tell it 
to use another default route from elsewhere in the mesh. What I was 
hoping is that Babel would install multiple default routes, with metrics 
that reflect the speed of the relevant internet connection. So the 
router for a particular site might have its own default route with 
metric 500, and get a route from elsewhere in the mesh via Babel with a 
lower metric. That isn't happening. It seems that Babel will not put its 
own proto route into the table, if there is a static route already 
configured.

I've tried playing with "allow-duplicates 20", but Babel crashed (1.10). 
I poked at babel-pinger despite the warnings (:-)) but was unable to 
figure that out.

Any other suggestions?

For reference on of the hosts babel.conf looks like this:

# For more information about this configuration file, refer to
# https://www.irif.fr/~jch/software/babel/babeld.html
pid-file /var/snap/babeld-sabdfl/common/pid
log-file /var/snap/babeld-sabdfl/common/log
state-file /var/snap/babeld-sabdfl/common/state
link-detect true
reflect-kernel-metric true
interface bond-lan type wired rxcost 100
interface bond-plein-1 type wired rxcost 24
interface bond-plein-2 type wired rxcost 23
interface bond-protea-1 type wired rxcost 25
interface bond-protea-2 type wired rxcost 26
interface bond-peer type wired rxcost 55
redistribute ip 0.0.0.0/0 eq 0 metric 128
out ip 0.0.0.0/0 ge 32 deny
redistribute ip 192.168.0.0/16 ge 24 allow
redistribute local deny

Mark