[54124] in North American Network Operators' Group
RE: FW: /8s and filtering
daemon@ATHENA.MIT.EDU (Todd A. Blank)
Tue Dec 10 17:02:24 2002
Date: Tue, 10 Dec 2002 17:02:27 -0500
From: "Todd A. Blank" <todd@ipoutlet.com>
To: <bmanning@vacation.karoshi.com>, <hnarayan@cs.ucsd.edu>
Cc: <nanog@merit.edu>
Errors-To: owner-nanog-outgoing@merit.edu
Thank you! I thought that was the whole point of CIDR...
-----Original Message-----
From: bmanning@vacation.karoshi.com
[mailto:bmanning@vacation.karoshi.com]=20
Sent: Tuesday, December 10, 2002 4:54 PM
To: Harsha Narayan
Cc: bmanning@vacation.karoshi.com; nanog@merit.edu
Subject: Re: FW: /8s and filtering
but there is no "class C space" anymore. there is no "class A space"
either. its all CIDR space and some providers have retained some
vestigal classfull concepts in the creation/maintaince of their routing
filters. a /24 may or may not get you past my filters. any you'll have
no way to know until/unless you try to get to my sites or we develop
a peering relationship.=20
wrt the evolution of filters. yes, they do evolve. and so does ARIN
policy. you presume too much to second guess that ARIN policy will=20
evolve in the way you outline.=20
>=20
> Hello,
> Thank you very much everyone for all your replies. When Class C
space
> gets used up, wouldn't the filtering policies have to change to allow
the
> same kind of multihoming from the Class A space. Currently, a /24 from
> Class C is enough to get past filters. However later, a /22 (or is it
/20)
> from Class A would be required to get past filters.
>=20
> Since there are only three /8s left in Class C, I was curious
whether
> filtering policies would change to accommodate this.
>=20
> If filtering policies won't change ARIN will have to change its
> multihoming PA policy to giving away a /22 instead of a /24. Though
> officially it is RIR policy not to worry about the routability of an
> a prefix I guess they do worry about it?
>=20
> Thanks,
> Harsha.
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>=20
> On Tue, 10 Dec 2002 bmanning@vacation.karoshi.com wrote:
>=20
> > >
> > >
> > > Hello,
> > > Now I am confused because I have got two sets of contradicting
answers.
> > > Some say that anyone can multihome, some say that you need to be
of a
> > > certain minimum size to multihome. May I know what is the right
answer?
> > >
> > > I agree that allowing anyone to multihome would increase the
size of the
> > > routing table. So does this mean that someone has to be of a
certain size
> > > to multihome?
> > >
> > > Harsha.
> > >
> >
> > anyone can multihome, with the cooperation of others.
> > current practice seems to dictate that the standard
> > operating procedures to protect the integrity of
> > the routing system mandate that only prefixes of
> > certain lengths are allowed at -SOME- isp boundaries.
> >
> > you seem to have the assumption that there is a single
> > standard here. There is not.
> >
> > --bill
> >
>=20
>=20
>=20
>=20
