[AfriNIC-rpd] AFPUB-2006-GEN-001 and Anycast

[Alan Barrett]

On Fri, 06 Apr 2012, Graham Beneke wrote:
>I don't know of any practical way to carve a single /24 out of a /18. 
>Then to announce that /24 to certain peers but not announce to others 
>and still ensure well aggregated announces of the /18.

What's wrong with the obvious approach?  Like this:

1. get a /18 block.
2. carve out a /24 from inside the /18.
3. announce the /18 to everybody.
4. announce the /24 to only some peers.

Not so obvious:

5. optionally, tag the /24 with a special community to encourage your
    peers not to propagate the announcement further.  Perhaps no-export
    would be a reasonable choice.

>If the member could receive one additional /24 then they could 
>announce the following:
> * /24 prefix
> * /18 prefix
>
>The alternative is to announce:
> * /24 prefix
> * /19 prefix
> * /20 prefix
> * /21 prefix
> * /22 prefix
> * /23 prefix
> * /24 prefix

I don't see why those are the only alternatives.  
Have you forgotten the longest-match rule?

--apb (Alan Barrett)