Re: Updated IID length text

Lorenzo Colitti <lorenzo@google.com> Thu, 19 January 2017 04:26 UTC

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From: Lorenzo Colitti <lorenzo@google.com>
Date: Thu, 19 Jan 2017 13:25:39 +0900
Message-ID: <CAKD1Yr1cSPBacrk2tZAOOGwR4nSU2NYSrV5ArZLBrOoXTcBNTw@mail.gmail.com>
Subject: Re: Updated IID length text
To: Fernando Gont <fgont@si6networks.com>
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On Thu, Jan 19, 2017 at 1:20 PM, Fernando Gont <fgont@si6networks.com>
wrote:

> > It does make sense. /48 does impact things substantially. However, on
> > like like wifi, the MAC address is the endpoint identifier, so if
> > there's a duplicate MAC you can't get on the network.
>
> Could you please explain how you do the math such that in these two
> scenarios:
>
> #1: SLAAC with 48-bit IIDs, where the IID is a random string of bits
>     (e.g. as resulting from RFC7217)
>
> #2: Traditional SLAAC with 64-bit IIDs, where the IID is generated from
>     a randomized MAC address (and in which, based on how MOdified EUI64
>     IIDs are generated, you have to embed the fixed 16-bit word 0xfffe
>     in the IID)
>

You forgot the "where layer 2 ensures that there are no duplicate MAC
addresses on the network" part of this scenario.