AS number assignment criteria

In <9407190931.AA00436 at rijp.ripe.net>, <Marten.Terpstra at ripe.net> wrote:

>  * 3 - "To identify single-homed ASes."
>  * They connect to a service provider or to another enterprise and
>  * use external routing. The other end tells them they need an ASN.
>  * Strictly speaking they do not need one, because they can only have
>  * one external policy.
> 
>  * The question now is: Should we assign ASNs to those in category 3 
>  * who request it because their ISP requires it?
>  * This is a potentially large number.
>  * 
>  * Opinions?
> 
> Potentially the ISP can request an AS because it can enforce a
> stricter policy on its client than on its own AS. It can for instance
> say that the customer AS will not be announced to XX where the AS of
> the provider itself could be announced to XX. Unlikely, but a
> different policy possibly needing an AS......

I tend to agree with Marten here. We have a number of down-stream
providers who buy transit from us, and find it virtually essential
to be able to distinguish their routes from ours using AS number, to
provide a clean adminstrative boundary. An example of Marten's
principle (to pick a hot topic :-), is where the downstream provider
is not a CIX member, but the upstream one is.

I think therefore the rule is that category 3 sites can receive an
AS number if they are a re-seller of some kind, rather than just a
retail customer.  In practice, a resale provider might well be
expected to set up peerings with other providers on their own in the
future, so putting an AS number in now also helps future-proof
things.

Of course, it can often be hard to define "re-seller" or
"provider"in some circumstances, I suppose an alternative rule could
be that they need to have some minimum number of aggregates to
qualify, it is clearly worthless to set all this up if they only
have one.

Keith Mitchell                 Network Manager

Public IP Exchange             keith at pipex.net
216 The Science Park           keith at unipalm.co.uk
Cambridge, UK
Phone: +44 223-250120
Fax:   +44 223-250121          PIPEX is a subsidiary of Unipalm Group PLC