Questions about anycasting setup

Mehmet Akcin mehmet at
Fri Mar 9 02:23:55 CST 2012

On Mar 9, 2012, at 12:11 AM, Elmar K. Bins wrote:

>>>  3. IPv6! - Is /32 is standard? We have only one /32
>>>  allocation from ARIN and thus if using /32 seems like hard deal - we have
>>>  to likely get another /32 just for anycasting? or we can use /48 without
>>>  issues? Also, is /48 a good number for breaking /32 so that we can do /48
>>>  announcements from different datacenters in simple uni casting setup?
>> A /48 is quite reasonable.  Announcing a whole /32 just for your anycast service would be wasteful.
> Why? It's simply another prefix, no matter how big. It might look
> wasteful, but if *that* is the allocation you *have*, it's the
> one you ought to use.
> One should be careful - people do filter on allocation lengths, so
> breaking out a /48 out of a /32 allocation and advertising it on its
> own can lead to it being filtered.

if you know anyone who is filtering /48 , you can start telling them to STOP doing so as a good citizen of internet6.

I agree with Woody anything more than /48 for anycast is waste.


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