Subject: Re: I-D Action:draft-vandevelde-v6ops-harmful-tunnels-00.txt

From: Brian E Carpenter <[email-masked]>
Date: Wed, 08 Jul 2009 17:55:13 +0100

Hi,

>    A subset of the available tunnels has the property of being
>    non-deterministic (i.e. 6to4 [RFC3056]

That's inaccurate. The tunnels described in RFC3056 are not
non-deterministic; they are determined by routing configuration.
(They are asymmetric, but that's another discussion.)

The tunnels created by the anycast extension of 6to4 in
RFC3068 are non-deterministic, or at least unconfigurable,
and that's where the black holes come from.

   Brian

P.S. I don't think that observing that such tunnels are
problematic is going to achieve much. Advising how to
minimise the problems seems more useful; e.g.
draft-nward-6to4-qualification