Re: using IPv6 address block across multiple locations

[Owen DeLong <owen () delong com>]

On Nov 1, 2011, at 4:10 AM, Justin M. Streiner wrote:

> On Tue, 1 Nov 2011, Dmitry Cherkasov wrote:
>
> > case 2: extranet like multiple POPs interconnected with VPNs
> > - get greater then /48 block (like /44) so each POP gets its /48 part
> > - each POP announces its corresponding /48 prefix to their local ISPs
> > - decide if you wish that traffic from Internet to some POP passes
> > through some other of your POPs (security or other considerations); if
> > this is desirable you may announce the whole aggregate (like /44)
> > additionally to /48 from all or some of the POPs; optionally you may
> > wish to announce /44 with community 'no-export'
>
> You really don't need to tag the larger block with no-export.  In fact,
> if the POPs are suitably interconnected on the back end, you really
> don't need to advertise the /48s all, and just advertise the /44. Depending on your upstreams, you might be able to 
> tag your advertisements with certain BGP communities (will vary from provider to provider) to give you some degree of 
> conrol over traffic distribution.
>
> Getting back to the original point, unless someone does something odd with their BGP views, the /48s will be 
> preferred because they're smaller (more specific), and the /44 would only be used if a corresponding /48 prefix 
> doesn't exist in their BGP view.
>
> jms

In fact, if you have one or more providers which, in common, serve
multiple POPs, it may be desirable to tag the more specifics (/48s)
as no-export and leave the /44s exportable.

In this way, you can avoid unnecessary DFZ pollution.

Owen