[146064] in North American Network Operators' Group
Re: using IPv6 address block across multiple locations
daemon@ATHENA.MIT.EDU (Owen DeLong)
Tue Nov 1 11:25:37 2011
From: Owen DeLong <owen@delong.com>
In-Reply-To: <Pine.LNX.4.64.1111010703300.8660@whammy.cluebyfour.org>
Date: Tue, 1 Nov 2011 08:20:40 -0700
To: "Justin M. Streiner" <streiner@cluebyfour.org>
Cc: nanog@nanog.org
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org
On Nov 1, 2011, at 4:10 AM, Justin M. Streiner wrote:
> On Tue, 1 Nov 2011, Dmitry Cherkasov wrote:
>=20
>> 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'
>=20
> 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.
>=20
> 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.
>=20
> 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
