Re: [babel] Restarting nodes and seqno requests

[Juliusz Chroboczek <[e-mail]>]

>>> My implementation of the randomisation only randomises the top 32 bits,
>>> so there's still a stable identifier. Maybe it would make sense to
>>> default to this behaviour?
>> 
>> That would break the optimisation of using the low bits of the IPv6
>> address to encode the router-id.

> Bird doesn't do that anyway.

That's five lines of code, and saves almost half the traffic in pure IPv6
meshes.

>> I'm not sure how you'd avoid router-id collisions, though.

> By chance? With 32 bits of randomness, even in a moderately sized
> network the chance of collision is quite low (which means that it will
> not happen until it is the most inconvenient, of course...) :)

With 100 nodes, probability of collision is 10^-6.  With 1000 nodes, it's
10^-4.  With 2000 nodes, it's 5*10^-4.  With 5000 nodes, it's 3*10^-3.

I think we're at the very edge of comfort, which is why I chose 64 bits in
the first place.

>> I'll try to find some time to make a new revision tomorrow, if you'd
>> like to send me a patch, I'd be grateful. (No promise to keep your
>> wording, though.)

> No promises to send any either ;)

We have a deal.

-- Juliusz