And Now for Something Completely Different (was Re: IPv6 news)

Fred Baker fred at cisco.com
Mon Oct 17 21:43:16 UTC 2005


we agree that at least initially every prefix allocated should belong  
to a different AS (eg, no AS gets more than one); the fly in that is  
whether there is an ISP somewhere that is so truly large that it  
needs two super-sized blocks. I don't know if such exists, but one  
hopes it is very much the exception.

The question is "does every AS get a prefix". Under current rules,  
most AS's assigned to edge networks to support multihoming will not  
get a prefix. I personally think that's probably the wrong answer  
(eg, you and I seem to agree on PI space for networks that would  
warrant an AS number does to size, connectivity, and use of BGP to  
manage their borders), but it is the current answer.

On Oct 17, 2005, at 2:06 PM, Per Heldal wrote:

>> The RIRs have been trying pretty hard to make IPv6 allocations be  
>> one prefix per ISP, with truly large edge networks being treated  
>> as functionally equivalent to an ISP (PI addressing without  
>> admitting it is being done). Make the bald assertion that this is  
>> equal to one prefix per AS (they're not the same statement at all,  
>> but the number of currently assigned AS numbers exceeds the number  
>> of prefixes under discussion, so in my mind it makes a reasonable  
>> thumb-in-the-wind- guesstimate), that is a reduction of the  
>> routing table size by an order of magnitude.
>
> I wouldn't even characterise that as being bald. Initial  
> allocations of more than one prefix per AS should not be allowed.  
> Further; initial allocations should differentiate between network  
> of various sizes into separate address-blocks to simplify and  
> promote strict prefix-filtering policies. Large networks may make  
> arrangements with their neighbors to honor more specifics, but that  
> shouldn't mean that the rest of the world should accept those.



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