[Babel-users] Babel configuration with AP/STA mode.

[Juliusz Chroboczek]

Hi Mason,

> I would like to test babel protocol which is based on a distance vector
> routing protocol.

Cool.

> In case of a wired network, e.g., RIP and OSPF, link state routing protocol
> is generally known to be better than the distance vectour routing one due to
> fast convergence and loop-free property.

That is common folklore, but it's not true.

  - link-state is not intrinsically loop-free[1], it's just OSPF and
    IS-IS that eliminate loops in a timely manner due to the reliable
    flooding algorithm they use;
  - while naïve distance-vector (GGP, RIP) generates loops, there exist
    distance-vector protocols that are mostly loop-free (EIGRP, Babel,
    DSDV).

You may be interested in having a look at the slides of a lecture I've
just given on the subject,

  http://www.pps.jussieu.fr/~jch/enseignement/tbilisi2010.pdf

> In a wireless network, AODV and DSR has been working better than DSDV
> based on the distance vector one.

AODV is a distance vector protocol.  DSDV's poor performance is not
intrinsic to the protocol, it's due to having to wait for a periodic
refresh after each starvation event (slide 46).

> In addition, I also reviewed a paper which compared with various metrics
> such as babel, batman, and olsr. Babel and batman outperformed olsr.

OLSR is a very naïve variant of link-state -- it uses unreliable
flooding.  I'm actually surprised it works as well as it does.

> Incredible.

Heh.

> In general, for running manet's routing protocols, each wireless system has
> to be set to an ad-hoc mode instead of AP or STA. In case of babel, all of
> the wireless system has to be set to ad-hoc mode in a mandatory manner?

> Unlike links between AP and STA, some wlan chipset working as ad-hoc mode
> has not supported full throughput due to some firmware errors. In a worst
> case, each wireless system cannot join the same cell infrequently. That' why
> I want to avoid using ad-hoc mode due to the existence of unpredictable
> characteristics. Instead of using an ad-hoc mode between wireless systems,
> can I still use the babel between AP and STA (Client), on which the babel is
> running separately?

Babel only requires the ability to transmit IPv6 multicast on a link;
a Wifi link in managed mode should be fine.

The issue is different: in managed mode, nodes cannot associate
arbitrarily: a STA cannot associate with a STA, an AP cannot associate
with an AP, and a STA can only associate with one AP at a time.

But if your network topology is such that this is not a limitation, by
all means, do try managed mode.

Regards,

                                        Juliusz