[Babel-users] scaling of babeld

[Juliusz Chroboczek]

> What do you think how well would a dynamic routed environment with
> babeld scale?

The Babel protocol has been designed to scale up to hundreds of thousands
of nodes.  The current implementations (babeld and BIRD) have not been
tested with more than a a thousand nodes or so.

Don't let this worry you, though: should you manage to break babeld with
your network, we'll try to quickly fix the implementation issues if you
help us with debugging.  (For example, Daniel Gröber reported an issue
with Babel authentication in his network on 2 May, he helped us a lot, so
the fix was in both babeld and BIRD on 18 May.)

(Note however that the size of the network might be limited by the
hardware: some hardware might be unable to install very large numbers of
routes.  This is a hardware limitation, and does not depend on the routing
protocol.)

> Do you think such a network could handle up to 1.000 OpenWrt nodes or
> even more?

Nexedi are running a commercial 800-node network with babeld.

> What real world bitrate would I be able to achieve?

Babel is designed so that the routing daemon doesn't look at data packets:
babeld informs the kernel in which direction it should pass packets (by
installing routes in the routing table), and then gets out of the way, so
the kernel or the hardware can push packets at full speed.

The appliance that you showed us is supposed to be able to push 830kpps
and 8.5GBps.  Assuming that the marketing literature is not lying, you
should be able to achieve that with Babel.

-- Juliusz