more specific routes in today reality

On Wed, Oct 10, 2001 at 10:04:22PM +0200, Havard Eidnes wrote:
>> On Tue, Oct 09, 2001 at 07:19:35AM -0700, Randy Bush wrote:
>> >> We are talking about different types of multihoming. I mean simple
>> >> multihoming situation when all multihomed customer's needs in routing are
>> >> covered by they upstream providers routing policies.
>> >                                                    ^
>> >note the use of plural above.  now read rfc 1930.
>>
>> Randy, rfc1930 consists of 563 lines. I suppose you are talking about:
>
>I think it's far simpler than that.  Quoting (and guessing):
>
>   To rephrase succinctly:
>
>      An AS is a connected group of one or more IP prefixes run by one
>      or more network operators which has a SINGLE and CLEARLY DEFINED
>      routing policy.
>
>I.e. a provider (an AS) can only have a single routing policy.
>
>However, I also sense some language confusion above, and that what
>you're trying to say is actually
>
> "a simple multihoming situation where any one of the multiple
>  uptstream providers' routing policy would be adequate for the client
>  in question"

Yes.

>However, I don't agree that it's a good idea to willfully cause the
>number of routes originated from different source ASes to increase.

If we are talking about theory -- agree, it's not a good idea.

>Furthermore, the routing complexity doesn't really rise as a function
>of the number of ASes -- it's rather the number of prefixes or perhaps
>rather the number of unique paths available which causes the entropy
>increase in the default-free zone which scares some of us.  In the
>bigger picture it doesn't really make any difference whether the more-
>specific route comes from PI or PA space or whether the route is
>consistently originated from a new AS or (shudder) separately from the
>two (or more) upstream providers; the entrypy increase in the default-
>free zone would be the same either way.

I agree with mentioned above statements about stability in "default-free zone".

But (AFAIK) according to measurements and statistics amount of free
AS-numbers are going to overflow more rapidly than free IPv4 address space.
I believe that sometimes AS-numbers space will be extended, but (AFAIK) it
requires global replacement of BGP-routing sotware.
In this situation ?RIRs? are looking for ?temporary? solution how to decrease
rate of AS-numbers allocation. One of such solutions (IMHO) is "more specific 
routes multihoming".

I don't have exact information about other RIRs, but RIPE NCC already 
_promotes_ such solution.

achieve multihoming) point of view adoption of such multihoming method, 
promoted by RIR, (sometimes) requires  changes in routing policies and
in what we are calling as "best practice". 

IMHO without new documents, recomendations, etc  new multihoming method 
is (mostly) useless.

Original posting was concerned in:

	- are there any already published/draft documents?
	- are there any plans to create such documents?

If there aren't, and if community aren't going to accept such technology 
(from our discussion it seems that now there isn't common opinnion), IMHO, 
RIR "snake the air to no purpose" - such technology is (generally) useless.

-- 
Regards,
Vladimir.