Re: [Idr] I-D Action: draft-ietf-idr-large-community-01.txt

[Nick Hilliard <[e-mail]>]

t.petch wrote:
> There is nothing IMHO in
> '   Global Administrator:  A four-octet namespace identifier.  This
>       MUST be an Autonomous System Number assigned by IANA.'
> which says whose ASN it is, just that it must be an ASN; if you allow
> IPv4 addresses, Router ID, IGP Area numbers and so on, anything else
> that fits into 32 bit, then it all breaks down so it MUST be an ASN.  At
> a stretch, that wording includes private ASN since those values are
> assigned by IANA although we might want to point that out explicitly.

There's something I'm not getting here in this discussion.

Let's step back a bit and start with a principal:  "if a policy cannot
be enforced, it is bad policy".

There is no way a priori for a router to have knowledge of what ASNs
have or have not been assigned, either by IANA or any other assignment body.

If a standards track document is created which mandates that a specific
identifier field "MUST" contain a ASN assigned by IANA, there is no
practical way for another router to check this.  Because the MUST cannot
be checked or enforced in any meaningful way, a formal requirement of
this form automatically falls into the realm of bad policy.

The best option here is - as Brian noted - to align with 1997 semantics
and make a recommendation to operators that the global administrator
field should be an ASN, and to stay well clear of attempting to define
what an ASN is, or is not. Operators are adults and will do what works
for them; there's no need to be over-prescriptive.

Nick