[j-nsp] BGP no-export community behavior special?

[James Bensley]

On 21 June 2018 at 15:09, Chris Adams <cma at cmadams.net> wrote:
> I'm testing some BGP policy changes, and I'm running into an odd thing.
> There are some routes that I don't want to export in general, but I do
> want to send them to a couple of specific eBGP neighbors.  For these
> routes, I've got an import policy that adds the no-export community.
>
> First, it appears that routes with the no-export community are
> automatically not exported to eBGP neighbors - that makes sense, but I
> didn't find that behavior documented anywhere (so my policies were
> explicitly rejecting no-export routes).
>
> It seems though that I can't strip the no-export community with an
> export policy.  Is that expected?  Is JUNOS not even passing no-export
> routes to the export policy for processing?

Hi Chris,

Have a look at https://tools.ietf.org/html/draft-ymbk-grow-wkc-behavior-02

Some operators are recommending not to use the well known communities
like "no-export" and instead allocate your own communities from your
own community numbering space which you treat the in the same way
within your BGP policies. This also helps to align the difference in
behavior between vendors went using "set community X" or "delete
community X", the behavior can change when that command references a
well known community vs. a non-well known community.

Cheers,
James.