[Babel-users] Losing seqnos at boot [was: Babel questions]

[Will Glynn]

On Oct 20, 2010, at 10:42 AM, Juliusz Chroboczek wrote:

> One workaround would be to reduce SOURCE_GC_TIME to 45 seconds; I'm fairly
> positive that this will not cause any rooting loops in practice.
> I don't recomment changing it to below twice the update time.

I'm hoping for faster convergence, so I'll consider that a fallback option.

> Another possibility would be to draw a new router-id at every boot,
> which will cause the stale loop-avoidance data in the network not to
> apply to the new incarnation.  (You can do that by commenting out lines
> 363 through 374 in babeld.c.)  The main flaw of this approach is that it
> will make it more difficult to administer and debug your network, since
> nodes will be using unstable node-ids rather than stable ids derived
> from a MAC address.

Hmm... that wouldn't be the end of the world. I'm already generating predictable IPv6 addresses (a /128 on loopback) based on hardware addresses, which is enough to identify neighbors and administer things. Plus, I'm working on over-the-air reporting of data from the local socket interface, so I could centralize the generated node-IDs pretty easily too.

> Finally, if the above workarounds are not satisfactory for you, we could
> consider extending the procol with a flag that says ``I've rebooted
> recently, please flush any loop-avoidance data you may have for me.''
> The Reserved field of the Router-Id message is just the right place to
> put such a flag (Section 4.4.7 in the Babel draft).

If this is desirable functionality and useful to others that don't have my particular mitigating factors, I'd be happy to implement it. Otherwise, I think I'll random node-IDs will work.

--Will Glynn