Re: Last Call: <draft-ietf-6man-rfc4941bis-10.txt> (Temporary Address Extensions for Stateless Address Autoconfiguration in IPv6) to Proposed Standard

[Nick Hilliard <[e-mail]>]

Lorenzo Colitti wrote on 10/09/2020 12:26:
> 1. I think it should not include section 3.3.2. The reason is that it 
> needlessly suggests an algorithm that is much more complex than simply 
> using an existing random number generator which all nodes likely already 
> have.

in theory you're probably right.  In practice, some vendors take serious 
short-cuts when it comes to prngs, particularly in the bulk-produced, 
low-cost device market. This will particularly be an issue for IoT and 
on wifi where DAD's single-shot approach is intolerant of loss.

3.3.2 only ensures that extra entropy is injected.  This probably isn't 
a bad thing.

Also the algorithm is based on rfc7217, so if there's a problem with 
this approach then that's possibly a wider discussion.

> 2. I think the text mentioning shorter IID lengths (3.3.1 bullet #2) is 
> not useful to implementers, because all it says is that it is possible 
> to implement a behaviour that for in all practical cases is forbidden by 
> RFC 4291.

It refers non-normatively to 7421, which provides a useful and nuanced 
discussion of the issue.  There doesn't seem to be any particular 
ambiguity here?

Nick