Re: [v6ops] "The Internet is for End Users" (Re: I-D Action: draft-ietf-v6ops-unique-ipv6-prefix-per-host-07.txt)

[Fernando Gont <[e-mail]>]

On 08/17/2017 12:12 PM, Tim Chown wrote:
>> On 17 Aug 2017, at 04:01, Lorenzo Colitti <[e-mail]> wrote:
>>
>> On Thu, Aug 17, 2017 at 11:51 AM, Mark Smith <[e-mail]> wrote:
>> "If IPv6 IIDs were reduced to something like 32 bits, would any of the
>> above be impacted:
>>
>> - Available and Reliable: No. May have a positive influence, as
>> availability and reliability possibly could be increased, as ND cache
>> resource exhaustion attacks effectiveness would be reduced.
>>
>> Actually the answer here is also "yes, negatively". It means that networks with large numbers of users would become unreliable because of IID collisions. There are networks that run 10k or 20k nodes on a single subnet. Large corporate networks are an example, or large conferences such as MWC.
> 
> Is there info anywhere on what the common OSes do when they encounter a DAD failure - do they give up or try a new tentative address?  


For legaxy (pre RFC7217) they give up -- after all, you wouldn't know
how to form a new IID if you have to base it on the undelying link layer
address.

-- 
Fernando Gont
SI6 Networks
e-mail: [e-mail]
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