Re: v6ops-routing-guidelines ID

[Colm MacCarthaigh <colm@stdlib.net>]

On Mon, Mar 19, 2007 at 03:50:09AM -0600, Danny McPherson wrote:
>    The default unicast route (::) may be advertised in an IGP.  It must
>    not be advertised in an EGP unless it has been requested by the
>    recipient.

Is this really wise anyway? Firstly, it should probably be "::/0"
, :: is a whole different route on most systems, but that's just
anal pedantry.

But is using :: as a default unicast route wise? Why not 2000::/3?
If you use 2000::/3 then many common errantly routed packets 
start to fail RPF checks more quickly, examples include the many
types of packet that have :: as an on-the-wire source address
(e.g. MLD) that ocasionally end up being routed when they shouldn't
be, and of course spoofed and corrupted sources outside of 2000::/3.

That said, I don't have any statistics on whether any vendors have
particular optimisations for the ::/0 route or if it's a typical
depedency for multicast forwarding. (though here it says unicast route).

I can understand ::/0 being in an IGP, because the AS might have
internal non-globally routed unicast packets, but why would it be a good
idea for ::/0 to be advertised in an EGP at all. Why forward packets we
know to be globally unroutable?

-- 
Colm MacCárthaigh                        Public Key: colm+pgp@stdlib.net