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[AfriNIC-rpd] Anycast prefix's

Andrew Alston aa at
Fri May 11 12:38:57 UTC 2007


The problem with that is this:

If you apply for 2 /24s, one for anycast and one for unicast.  You fully
utilize your /24 for unicast.  Your anycast is used for 3 DNS's servers,
so you total space usage is actually one /24 + 3 DNS server addresses.
This means that when you apply for more space, your utilization is only
51%, at this point, you will probably get denied new space.

Also, because P.I space is assigned in blocks of /22 etc, you need to be
able to apply for a single /24 for anycast for a specific purpose in
order to avoid deaggregating your blocks.

For example, I apply for an address block, I get given

I want to anycast across the globe.  So I put down my anycast servers
and I either ask other people to announce the space under their ASN's
(which means same space, different origins, which unless the prefix is
specified as anycast in route-objects etc could cause confusion), or I
announce my asn's directly from the DNS servers (which would also work).
However, I have now got 2 routes in the routing table, one for the and one for say as the anycast prefix,
though they are the same block, and that's just... ugly :)



-----Original Message-----
From: rpd-bounces at [mailto:rpd-bounces at] On Behalf
Of Frank Habicht
Sent: Friday, May 11, 2007 2:02 PM
To: AfriNIC Resource Policy Discussion List
Subject: Re: [AfriNIC-rpd] Anycast prefix's

On 5/11/2007 2:08 PM, Andrew Alston wrote:
> Hi All,
> Before I actually type up and submit a policy proposal, I wanted some
> opinions on the adoption of a policy regarding the allocation of /24
> prefix's for the purpose of anycast.


I think an average PI /24 will do the same job.
Unless I'm missing something....?

Frank Habicht

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