FW: /8s and filtering

Harsha Narayan hnarayan at cs.ucsd.edu
Tue Dec 10 20:13:49 UTC 2002

  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.

  Since there are only three /8s left in Class C, I was curious whether
filtering policies would change to accommodate this.

  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?


On Tue, 10 Dec 2002 bmanning at vacation.karoshi.com wrote:

> >
> >
> > 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

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