using IPv6 address block across multiple locations

Tue Nov 1 11:10:19 UTC 2011

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