Wolfgang Tremmel wrote:
> From my reading of RFC1997 and RFC7947 the ambiguity is not really one:
> 
> RFC1997 states that any community-aware BGP speaker MUT NOT advertise 
> prefixes received with NO_EXPORT
> --> a route server is a BGP speaker
> --> it is community aware
> 
> RFC7947 uses wording SHOULD NOT and MAY which IMHO are weaker. 

It's formally ambiguous:

>    If a Communities attribute is intended for processing by the
>    route server itself, as determined by local policy, it MAY be
>    modified or removed.

i.e. the ixp operator explicitly has the option to interpret communities
or not.  This reflects the operational reality that some IXPs have
chosen to interpret and some to pass through.  Each has carefully
considered reasons for doing what they do.

>From a practical point of view, without a statement of intent from the
IXP operator, you cannot know whether a particular IXP will interpret
NO_EXPORT or forward it.

Because of this practical ambiguity, clarity would be useful.

Nick

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