[138458] in North American Network Operators' Group
Re: IPv4 address shortage? Really?
daemon@ATHENA.MIT.EDU (Steven Bellovin)
Tue Mar 8 08:46:16 2011
From: Steven Bellovin <smb@cs.columbia.edu>
In-Reply-To: <42008.1299591179@localhost>
Date: Tue, 8 Mar 2011 08:43:53 -0500
To: Valdis.Kletnieks@vt.edu
Cc: nanog@merit.edu
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Mar 8, 2011, at 8:32 59AM, Valdis.Kletnieks@vt.edu wrote:
> On Tue, 08 Mar 2011 07:37:27 EST, Steven Bellovin said:
>=20
>> No. It was rejected because routers tended to melt down into =
quivering
>> puddles of silicon from seeing many packets with IP options set -- a =
fast
>> trip to the slow path. It also requires just as many changes to =
applications
>> and DNS content, and about as large an addressing plan change as v6. =
There
>> were more reasons, but they escape me at the moment.
>=20
> Steve, you of all people should remember the other big reason why:
>=20
> pathalias tended to do Very Bad Things like violating the Principle of =
Least
> Surprise if there were two distinct nodes both called 'turtlevax' or =
whatever.
> That, and if you think BGP convergence sucks, imagine trying to run =
pathalias
> for a net the size of the current Internet. :)
>=20
It wouldn't -- couldn't -- work that way. Leaving out longer paths (for =
many,
many reasons) and sticking to 64-bit addresses, every host would have a =
64-bit
address: a gateway and a local address. For multihoming, there might be =
two or
more such pairs. (Note that this isn't true loc/id split, since the =
low-order
32 bits aren't unique.) There's no pathalias problem at all, since we =
don't
try to have a unique turtlevax section.
--Steve Bellovin, http://www.cs.columbia.edu/~smb
