Re: [DNA-BOF] BoF Last Call on DNA WG Charter.

[Greg Daley <greg.daley@eng.monash.edu.au>]

Hi Bernard,

Bernard Aboba wrote:
>>Personally I guess that the main issues are:
>>
>>* That we've got a situation where hosts can have
>>   short disconnections every few seconds, (so we may
>>   have too much traffic)
>>
>>* That optimistic DAD has insufficent safety in the
>>   case of a collision (<hatoff> though I've read the
>>   draft and don't think this the case</hatoff>)
>>
>>* That it's not worth the effort to specify this until
>>   RFC2462bis is more concrete.
>>
>>Any opinions or additions?
> 
> 
> In general, this seems like a reasonable approach to me where the address
> has been allocated by stateless autoconfiguration.  Where the address is
> allocated by DHCPv6, I do not feel that DAD of any type is required on
> re-connection; a reachability test should be sufficient.

Indeed it may be, if nodes are consistent in
getting their addresses from the DHCPv6 server.
The current status from RFC-2462 is that hosts
DAD their addresses even if obtained from DHCP
on their original allocation.

This is not because of problems with DHCP lease
state, but because of autoconfiguring nodes (for
example, if A=1 in an RA).

I'd guess that the same types of autoconfiguring nodes
would be the 'troublemakers' for DHC hosts which
left a network temporarily and came back with a valid lease.

> In looking at the use of optimistic DAD I do not feel
> that the level of traffic is an issue;  optimistic DAD has
> an appropriate level of safety given the probability of collision.
> 
> It seems to me that optimistic DAD and RFC 2462bis can be developed in
> parallel.  The reality is that there are already implementations of
> optimistic DAD in progress so moving ahead is essential in order to
> prevent interoperability problems.

I think it may be difficult to keep the development
of one protocol in one group at the same rate as another
in a different group, though.

Thanks,

Greg