more specific routes in today reality

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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