Re: Comments on draft-yourtchenko-colitti-nd-reduce-multicast

[Ole Troan <[e-mail]>]

Eric,

>> do we need to care about link-locals? are they part of the problem we
>> need to solve?
> 
> Yes we do. They are about half the problem, an't they? More if most
> traffic is local to the link. Less otherwise.

I think that's an important point for the problem definition.
I do agree with you that if we need to register link-local addresses too, and change the model of link-local addresses always being on-link, then we might look for other solutions. that's not what efficient ND seems to do though. as far as I can see the ND efficient draft suggests ND for link-local traffic is done like today.

I did a couple of packet captures on my relatively fruity home network. I did not see a single data packet using link-local addresses. I saw ND and I saw lots of mDNS (someone needs to solve that problem too).
I don't claim my home network is representative, but I'd really like to see more data here.
I presume we're not going to justify this work based on the 10000 node dentist's office (1)?

any application depending on link-locals would also break in the routed home case.

and if we really wanted to solve it, what's the solution space?
 - redefine link-locals to have an L-flag?
 - physically or virtually restricting the link-local subnet size?
 - disable link-locals?

cheers,
Ole

(1) couldn't find a good reference to this use-case, anyone knows?
      I only got http://ietfreport.isoc.org/idref/draft-ietf-dhcp-ipv4-autoconfig/