[freenet-dev] Weighted coin is better was Re: Moving to a simple coin was Re: Tunnels vs premix routing

[Michael Rogers]

Matthew Toseland wrote:
> Okay, so are we agreed on:
> - A pDrop of 5%, determined at each request/retry.
> - Some form of per-node failure tables (requires modifications to ULPRs).
> - Fatal DNFs.

All sound good.

> - On an RNF or an RO, we toss the coin again.

I don't think that's safe. Moving on if we get an RO or RL is fine, even 
without tossing the coin again, but an RNF has visited some nodes 
(potentially a lot of nodes). We shouldn't ever branch with probability 
greater than pDrop, otherwise the average branching factor could be 
greater than 1 under some circumstances, at which point the end times 
will be upon us.

In the case of RNFs, if we branch with probability 1-pDrop rather than 
pDrop as it sounds like you're suggesting, then we only need to get RNFs 
for pDrop/(1-pDrop) = 5.2% of requests on average to cause the sky to 
fall and fish to speak in tongues. (If that's not what you're suggesting 
then sorry for misunderstanding.)

> - Predictable mean visited nodes of 1/pDrop.

Only if we never branch, ie RNFs and DNFs are fatal (which might be the 
simplest solution).

Cheers,
Michael