[ppml] Policy to help the little guys

[Joe Maimon]

William Herrin wrote:

>On Thu, Mar 20, 2008 at 12:35 PM, Joe Maimon <jmaimon at chl.com> wrote:
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>
>> >>>Can you explain to me how a PI /24 would be in any way different from
>> >>>an otherwise identical PA /24?
>> >>In theory, filtering on RIR boundaries should be much safer if
>> >>multihoming with smaller prefixes was done with PA space.
>>
>> The difference would be in the likelyhood that the PA /24 is reachable
>> through the PA aggregate prefix even if it filtered. Hence, safer to filter.
>>    
>>
>
>Joe,
>
>Would not such filtering would defeat the purpose of multihoming in
>the first place?
>
>Regards,
>Bill Herrin
>  
>

For the filtered, yes. But not for the filterer.

That means a few things.

- PA /24 is encouraged to maintain connectivity with the P from the PA
- PI /24 is more desirable to the site that wants true multihoming
- PA /24 is more desirable for the sites that want to filter all those 
pesky multihomers
- Filtering PA /24  is more legitimate than PI /24, so that changes the 
"its broken, fix it" dynamic

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