Re: [DNA] [Issue 15] [Issue 16] DAD and MLD Interaction

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

Hi Nick.

Nick 'Sharkey' Moore wrote:
> On 2005-06-20, James Kempf wrote:
[cut]
>>Note that even if we do change the state to Optimistic, there is still the
>>issue I raised about the node originating packets with a topologically
>>incorrect source address if it has moved to a new IP link. The only way to
>>prevent that from happening is to make the addresses Tentative (and suppress
>>the DAD NS until after the RA returns) until the node actually finds out in
>>the RA whether it actually has moved to a new IP link or not.
> 
> 
> Yeah, I think the safest thing is to Deprecate any addresses at Link
> Down, and Tentative/Optimistic them at Link Up.  That should allow
> source address selection to behave correctly in the case of multiple
> interface devices as well.

This may be the safest way (making them deprecated) but may also result
in devices having no non-::1 addresses available to applications when
they receive a (momentary) link-layer down indication.

(Just asking): Is this appropriate behaviour?

It would be good to have an applications perspective on this...

Perhaps it would be OK in a MIPv6 environment, since there could
always be a home address to bind to, even if it's no good for
routing to the internet at the moment while all links are down...

Greg