BGP Community - AS0 is de-facto "no-export-to" marker - Any ASN reserved to "export-only-to"?'

Mark Tinka mark.tinka at
Wed Sep 9 12:59:55 UTC 2020

Well, the proposed de facto standard is only useful for what we need to
signal outside of the AS.

Since an operator will still need to design for communities used
internal to the AS (which will have nothing to do with the outside
world, and be of a higher number), they can accomplish both tasks in one
sitting; in lieu of first designing for internal use, and then trying to
design again for the external standard.

At any rate, as Nick said yesterday, if it's taken us over 2 decades to
agree on the well-known communities we have today, perhaps the industry
should go ahead and standardize this proposal anyway, and then see what
happens. If history has taught us anything, folk will do what they want
for 23 or so years, and even then, it might not turn out the way we hoped.

If it were me, I'd spend my time on other things. I can design internal
operator-specific communities that also do the right thing externally,
if needed. Heck, it's what I've done already. My customers are happy and
I have little incentive to fix that.

But that's just me :-).


On 9/Sep/20 14:47, Mike Hammett wrote:
> Exactly. There are far more pressing things when launching a new
> network than coming up with a BGP community scheme from scratch,
> learning everyone else's BGP community scheme, etc. If networks used a
> standard, then there is a very minimal ramp-up.
> -----
> Mike Hammett
> Intelligent Computing Solutions
> Midwest-IX
> ------------------------------------------------------------------------
> *From: *"Mark Tinka" <mark.tinka at>
> *To: *"Mike Hammett" <nanog at>
> *Cc: *nanog at
> *Sent: *Wednesday, September 9, 2020 6:47:13 AM
> *Subject: *Re: BGP Community - AS0 is de-facto "no-export-to" marker -
> Any ASN reserved to "export-only-to"?'
> On 9/Sep/20 13:41, Mike Hammett wrote:
>     How is that any different than any other network with minimal
>     connectivity (say a non-ISP such as a school, medium business,
>     local government, etc.)?
> Because the existing flexibility of dis-aggregated BGP community
> design can be done without any need to be in concert with the rest of
> the world, and your network won't blow up. There are far more pressing
> things to consider when launching a new network.
>     Also, it would likely help that new ISP in Myanmar learn their
>     limited upstream's communities if there were a standard.
> There used to be a very large global transit network that did not
> support BGP communities for their customers or peers. I'm not sure if
> that is still their position in 2020, but back then, it did not stop
> them from growing quite well.
> Mark.

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