[151130] in North American Network Operators' Group
Re: Shim6, was: Re: filtering /48 is going to be necessary
daemon@ATHENA.MIT.EDU (Darrel Lewis)
Mon Mar 12 14:51:50 2012
From: Darrel Lewis <darlewis@cisco.com>
In-Reply-To: <5BEB1E7E-8BF6-4432-9257-9F17B8100E01@muada.com>
Date: Mon, 12 Mar 2012 11:49:38 -0700
To: Iljitsch van Beijnum <iljitsch@muada.com>
Cc: NANOG Mailing List <nanog@nanog.org>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Mar 11, 2012, at 3:15 PM, Iljitsch van Beijnum wrote:
> On 11 Mar 2012, at 20:15 , Joel jaeggli wrote:
>=20
>>> The IETF and IRTF have looked at the routing scalability issue for a
>>> long time. The IETF came up with shim6, which allows multihoming
>>> without BGP. Unfortunately, ARIN started to allow IPv6 PI just in
>>> time so nobody bothered to adopt shim6.
>=20
>> That's a fairly simplistic version of why shim6 failed. A better =
reason
>> (appart from the fact the building an upper layer overlay of the =
whole
>> internet on an ip protocol that's largely unedeployed was hard) is =
that
>> it leaves the destination unable to perform traffic engineering.
>=20
> I'm not saying that shim6 would have otherwise ruled the world by now, =
it was always an uphill battle because it requires support on both sides =
of a communication session/association.
>=20
> But ARIN's action meant it never had a chance. I really don't get why =
they felt the need to start allowing IPv6 PI after a decade, just when =
the multi6/shim6 effort started to get going but before the work was =
complete enough to judge whether it would be good enough.
>=20
>> That fundementaly is the business we're in when advertising prefixes =
to more
>> than one provider, ingress path selection.
>=20
> That's the business network operators are in. That's not the business =
end users who don't want to depend on a single ISP are in. Remember, =
shim6 was always meant as a solution that addresses the needs of a =
potential 1 billion "basement multihomers" with maybe ADSL + cable. The =
current 25k or so multihomers are irrelevant from the perspective of =
routing scalability. It's the other 999,975,000 that will kill the =
routing tables if multihoming becomes mainstream.
When discussing 'why shim6 failed' I think its only fair to include a =
link to a (well reasoned, imho) network operator's perspective on what =
it did and did not provide in the way of capabilities that network =
operators desired.
=
http://www.nanog.org/meetings/nanog35/abstracts.php?pt=3DNDQ3Jm5hbm9nMzU=3D=
&nm=3Dnanog35
-Darrel=
