Minor comment: my understanding is that Reudiger was interested in getting more visibility in what happens between Adj-RIB-In pre- and post- policy.
I concur with Tim Evens comment “In order to determine what was "dropped/filtered/rejected/whatever" we do a simple diff between pre-policy and post-policy", which is essentially the same i replied to Reudiger as in what can be done with what we have. Speaking to pmacct users using BMP, the ability to diff pre- and post- policy was found good enough as a starting point to further research what happened to missing routes (through means external to BMP). It would be nice to get to some sort of increased visibility and have a kind of ‘exit code’, as Jeff Haas described it, when a route is filtered (‘f’ flag to be ported to Adj-RIB-In and Adj-RIB-Out?) and I reckon things may get complicated if trying to stretch the concept too much beyond this point. I’d be willing to contribute effort if it is found that there is enough interest. Paolo > On 20 Mar 2018, at 14:52, Job Snijders <[email protected]> wrote: > > Hi all, > > Reudiger Volk mentioned something interesting at the microphone > yesterday about getting more visiblity into BGP UPDATES that are > rejected/dropped somewhere in the policy chain transitioning from > Adj-RIB-In to Loc-RIB. > > To make a crude route-map example: > > ip prefix-list allow-ebgp-in permit 192.0.2.0/24 > ! > route-map ebgp-in permit 10 > match ip address prefix-list allow-ebgp-in > ! > route-map ebgp-in deny 20 > bmp-log-code 21438 > > It would be great to see what UPDATEs get dropped in "route-map ebgp-in deny > 20". > It would perhaps be quite useful if we can get to the point where you > can even attach custom policy-exit codes to the "Dropped Updates" send > in this new BMP feed. I can see how this makes operational life easier. > > RFC 4271 Section 9.1: "The Decision Process selects routes for > subsequent advertisement by applying the policies in the local > Policy Information Base (PIB) to the routes stored in its > Adj-RIBs-In. The output of the Decision Process is the set of > routes that will be advertised to peers; the selected routes will be > stored in the local speaker's Adj-RIBs-Out, according to policy." > > Perhaps a series of BMP "PIB" drafts are in order? > > Is this worthy of a new BMP draft? Are there volunteers? > > Kind regards, > > Job > > _______________________________________________ > GROW mailing list > [email protected] > https://www.ietf.org/mailman/listinfo/grow _______________________________________________ GROW mailing list [email protected] https://www.ietf.org/mailman/listinfo/grow
