RE: FW: more specific routes in today reality
Vladimir,
-----Original Message----- From: Vladimir A. Jakovenko [mailto:vovik@lucky.net] Sent: Wednesday, November 07, 2001 2:34 PM To: Koepp, Karsten Cc: 'nurani@ripe.net'; 'lir-wg@ripe.net' Subject: Re: FW: more specific routes in today reality
Nurani,
I was missing a RIPE NCC hostmaster statement to this e-mail. Sascha quoted a hostmaster. [..skipped..] <SNIP>
"- If PI is requested for multi-homing please explain why the second provider cannot route PA space as a more specific route (with the PA block holder adding a more specific route too)."
This was suggested from a RIPE NCC Hostmaster when sending a PI-space req. This looks a little contrary to your opinion doesn't it?
Sascha
Has this been a mistake, or is this the default answer to PI requests sent to the NCC nowadays? Is the NCC seriously going to recommend this to the members? I don't recommend the use of PI to customers either, and I don't want to roll up the multi-homing discussion. But PI should remain
On Wed, Nov 07, 2001 at 01:55:01PM +0100, Koepp, Karsten wrote: provider-
independent and PA should remain provider-aggregatable.
Quote from RFC1930, "Guidelines for creation, selection, and registration of an Autonomous System (AS)", page 7:
"With the introduction of aggregation it should be noted that a prefix may be represented as residing in more than one AS, however, this is very much the exception rather than the rule".
RFC1930 does not know PA or PI address categories, just routes.
Quote from RFC2725, "Routing Policy System Security", page 9:
"Route objects may exist for the same prefix with multiple origin AS values due to common multihoming practice that does not require a unique origin AS". RFC2725 does mention PI, but not the case where PA addresses are being multi-homed.
All I am saying is, regardless of whether we want this type of multi-homing or not, networks originating from different AS should use PI space. It does neither save a route nor address space to make pieces of a PA block multi-homed. It only binds the network to the provider assigning the PAs. That's why I was up-set. Still waiting for the NCC to answer... Karsten
Hi, On Wed, Nov 07, 2001 at 03:48:20PM +0100, Koepp, Karsten wrote:
All I am saying is, regardless of whether we want this type of multi-homing or not, networks originating from different AS should use PI space. It does neither save a route nor address space to make pieces of a PA block multi-homed. It only binds the network to the provider assigning the PAs. That's why I was up-set.
Whether or not an announcement is PI or PA has no influence on the number of routes visible in the global table. Using a sub-block from PA space has two advantages: - more flexible in block size (what if the customer comes back later and needs twice the space?) - more robust concerning filtering / dampening (the ISPs PA space will most likely be still visible, even if the sub-network is filtered somewhere) - if the customer goes away, the network can be given back and the route will disappear -> good for conservation *and* aggregation. The only benefit of PI is "you can keep your network if you change ISPs", which is convenient for the end customer but very expensive on the global routing system. This is why people actually ask for "stop handing out PI at all" (which I am *not* advocating here, but think about it). - and due to this pros and cons, which most people agree upon, the RIPE recommendations make sense. Gert Doering -- NetMaster -- Total number of prefixes smaller than registry allocations: 73128 SpaceNet AG Mail: netmaster@Space.Net Joseph-Dollinger-Bogen 14 Tel : +49-89-32356-0 80807 Muenchen Fax : +49-89-32356-299
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Koepp, Karsten