Thank you! I thought that was the whole point of CIDR... -----Original Message----- From: bmanning@vacation.karoshi.com [mailto:bmanning@vacation.karoshi.com] 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. 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 evolve in the way you outline.

Hello, Thank you very much everyone for all your replies. When Class C

gets used up, wouldn't the filtering policies have to change to allow

space 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?

Thanks, Harsha.

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

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Hello, Now I am confused because I have got two sets of contradicting

answers.

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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