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 16:08:30 UTC 2020

On 9/Sep/20 17:42, Robert Raszuk wrote:
> It's not about numbers ... it's about ability to uniformly express
> policy with chain of arguments. 
> See even with large communities you can define a policy with an
> unstructured parameter and single action then you need to put it on
> all of your boxes to act upon. 
> Is it possible to perhaps express it there to do what you need today
> or what you think is possible today. 
> Imagine if you would be sending BGP updates between your internal
> peers and tell each peer how to read the encoding ... Doable - sure.
> Good idea - not quite.

I see your logic.

I'm not sure I want to put that much faith in vendors, to be honest.
Just look at how the RPKI communities were cocked up in not-so-recent
releases of Junos.

Would vendor code shipping with pre-defined, more well-known communities
make life easier? Sure, in theory.

Do I want that and still seek a 3AM snooze when the team decide to run a
revision update? Based on my experience, probably not.

But, if vendors (and enough operators) are horny for this kind of thing,
best thing to do would be to build it and see how it actually fares in
the field.


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