Re: [Autoconf] RFC 5889 (Was: Call for comments to a new AUTOCONF charter proposal)

Emmanuel Baccelli <> Wed, 21 July 2010 09:58 UTC

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From: Emmanuel Baccelli <>
Date: Wed, 21 Jul 2010 11:58:19 +0200
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Subject: Re: [Autoconf] RFC 5889 (Was: Call for comments to a new AUTOCONF charter proposal)
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Hi Erik,

On Fri, Jul 9, 2010 at 10:52 PM, Erik Nordmark <>wrote;wrote:

> ...

> The result is that the document can easily be construed as discouraging
> approaches that make a lot of sense, which seems counterproductive.
> An example of such an approach is a routing protocol which uses IEEE MAC
> addresses as router ids, assigns IPv6 link-local addresses to the router's
> interfaces and uses that in the routing protocol exchanges, and configures
> global addresses for use by applications.

Using MAC addresses for unique identifier is considered dangerous by many
people, as MAC addresses are not always unique. There were several cases
where an order of several thousands of devices where shipped with the exact
same MAC address, by mistake. Moreover, MAC addresses can be altered almost
at will. This is why relying on MAC addresses for unique identifiers is not
sufficient in my mind. It's merely another way to say: "let other people
worry about our problems". This rarely works reliably.

As to using link local addresses, there are many cases where it is not
appropriate, as discussed over and over in this working group and elsewhere.
If you have any comments on
 please let us know. The fundamental properties of multi-hop wireless
communications described in that document make it difficult to use
link-local addresses in many cases.

And again, the goal of RFC5889 is not to describe all possible addressing
models for each specific scenario, but rather to describe one specific model
with which we have experience in multi-hop wireless contexts, and which has
proven to work OK. In that respect, I think RFC5889 does the job.