On Wed, May 28, 2003 at 01:07:08PM +0200, Gert Doering wrote:
Hi,
On Wed, May 28, 2003 at 10:45:44AM +0100, Carlos Morgado wrote:
On Tue, May 27, 2003 at 09:07:05PM +0200, Gert Doering wrote:
The *benefit* of "/48 multihoming" is that you can filter those routes if you don't want to see them - then your routers will send packets down the /32 road, and eventually hit a router that knows about the /48
This is exactly why providers will have an hard time selling this to customers. 'It may work, it might not, depends, you have no control and neither do we'.
One of us us confused about this, and it's not me.
A /48 from an aggregate is MUCH MORE reliable than a /48 that has no fallback aggregate. If the latter is filtered (or flap-dampened, or "lost" due to bad as-path filters, or however), you're dead. If the former is lost, you can always send packets in the direction of the aggregate, and at a certain proximity, the /48 will be visible again and be used for proper packet delivery.
Ok, I wasn't clear - I was strictly speaking about broken up PA space, not PA /48 vs. PI /48. You're right, if people per rule filter at /32 PI /48 is worse. If people per rule filter at /48 (which seems to be a requirement for this scheme to work) then /48 PI is better as it permits traffic engineering by the multihomed network. I mean, if you multihome and know for a fact at least half of the internet won't see one of your links (either because of filters or sumarization) what's the point ? If you do know /48s will indeed be visible by most of the internet using PI results in the same number of entries as PA, allows better control by the multihomed network and given a carefull allocation policy (now that IPv6 space is plenty and sparse) allows to grow the /48(s) into bigger allocations with minimal disruption.
Besides this, I hope you're not selling *any* service related to Internet connectivity to your customers with the claim that you have any control about things more than two AS hops away from your network...? Because you haven't.
No, I'm selling in technical good faith. I currently take steps to maximize the quality of the transit I sell considering the current IPv4 framework and current practices. In my opinion however with the /48 PA method I can't in good faith sell the same level of service. cheers -- Carlos Morgado <chbm@cprm.net> - Internet Engineering - Phone +351 214146594 GPG key: 0x75E451E2 FP: B98B 222B F276 18C0 266B 599D 93A1 A3FB 75E4 51E2 The views expressed above do not bind my employer.