Thomas, On Wed, Jul 29, 2015 at 05:43:42PM +0000, Thomas King wrote: > > On 28 Jul 2015, at 17:34, Jeffrey Haas <[email protected]> wrote: > > One thing I'd recommend for the draft is explicit discussion about the scope > > of the community and its expected propagation characteristics. > > I just uploaded a revised version of the draft. It contains an overhauled > section 3 (Operational Recommendations). Does this contain what you > recommended?
Things are better. As you note below you say: > > The simple > > fact is that even with some implementations or operators who strip this > > community themselves for scope, it'll leak. Plan for the leak > > operationally. > > We did - we changed “3.2. Local Scope of Blackholes” so that a BGP speaker > receiving an BGP announcement tagged with the BLACKHOLE community SHOULD add > a NO_ADVERTISE, NO_EXPORT or similar communities. The issue we've had over the years is that the propagation communities get stripped or failed to get added and leak. Part of the question is whether we should also have a stronger check: If a route is tagged with blackhole, and it is more than one AS-hop away, should we discard the route? (Or mark ineligible for selection.) I think my concern here is that someone marks an existing route with the blackhole community and we can't readily determine whether the blackhole behavior should be dropped or not. In the presence of RPKI ROA, it's easier to note that someone is misoriginating a route and we can tell. But determining what to do seems tricky. Please note that these criticisms are not specifically directed to this draft. This is a set of known consequences of such blackhole communities. -- Jeff _______________________________________________ GROW mailing list [email protected] https://www.ietf.org/mailman/listinfo/grow
