Re: more specific routes in today reality
- Date: Tue, 9 Oct 2001 12:15:57 +0200
Hi,
On Tue, Oct 09, 2001 at 01:10:49PM +0300, Vladimir A. Jakovenko wrote:
> According to my observations at least since this summer the RIPE NCC staff
> promotes usage of more specific PA routes (originated by more than one AS)
> for multihomed customers opposite to the "classic" scheme with PI addresses
> (or new enterpise LIR ;-).
>
> In this situation we are going to expect increase of ammount of:
>
> 1. Routes with more than one origin.
No - the more specifics are announced by the customer AS *only* (and the
upstream AS that this blocks belongs to will permit them "through").
> 2. Less specific routes within existing more specific.
Yes.
> Actual (ripe-185) document of "IPv4 and ASN Policies in the RIPE NCC Service
> Region" and working draft (on http://www.ripe.net/rs/ipv4policy.html)
> refer to rfc1930 which contains section 7 - "One prefix, one origin AS":
Yes, but this is a non-issue here.
[..]
> According to measurements on RIPE DB dump on Oct 4 there were about 17% of
> prefixes with more than on origin AS. It isn't just RIPE specific -
> measurements from other IRRs are close.
This is well possible, but not a necessity for this type of multihoming -
to the contrary, in most cases it's a mistake or a transitional thing.
> Announcement of less specific routes within existent more specific route
> (lets assume that there is no bgp routing process misconfiguration - both,
> less and more specific, routes have route objects) clashes with an aggregation
> issues promoted in many RIPE documents.
Yes, but looking at the overall table, it's beneficial.
- you have the same amount of routes as with "small PI", so it's not worse
- if one is filtering "no /24's", the end site is *still* be reachable,
which would not work with PI space.
[..]
> Unfortunately it is difficult to dispute such policy unactuality without
> appropriate documents. Is it possible at least "to legalize" applicability
> of more specific routes with more than one origin for multihoming purposes
> in ripe-185 successor?
RIPE has no power about *routing*. But there has been talk on the last
meeting about writing a BCP concerning routing issues and recommendations
(I have no idea what the state of this is or whether anybody is working
on it).
Gert Doering
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