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Re: DAD question

Ole Trøan <otroan@employees.org> Sat, 11 August 2012 08:33 UTC

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Sender: Ole Troan <ichiroumakino@gmail.com>
Subject: Re: DAD question
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From: Ole Trøan <otroan@employees.org>
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Date: Sat, 11 Aug 2012 10:33:51 +0200
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To: Fred Baker <fred@cisco.com>
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Fred,

> Call this "making sure I'm on the same page as anyone else"…
> 
> RFC 4941 describes privacy addresses, and RFC 4291 describes an EID based on a MAC Address. RFC 4862 describes stateless address autoconfiguration, and uses RFC 4861's duplicate address detection mechanism.
> 
> My question is: what happens if any of them discovers that it has created an address that is already in use in the network?
> 
> There would appear to be two options: 
> (1) "ah, OK, I guess I didn't really want to talk today"
> (2) Following RFC 4941, guess again until one creates a unique address
> 
> Is it fair to assume that implementations do DAD and follow (2)?

implementations I'm familiar with do 1.
it may be a fair assumption that if an address based on the MAC address is duplicate, the MAC address itself is a duplicate.

cheers,
Ole

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