On Wed, Apr 20, 2016 at 04:13:13PM +0100, Paul Jakma wrote: > The application I developed it for. Being able to take down routers in a > staged way [...] > The OSPF WG is actually standardising behaviour for that. It's useful > enough they've re-allocated a previously allocated and very precious > OSPF option bit for it.
Mhm... things got mixed up somewhere. The OSPF WG is pushing along the H-bit for systems that want the OSPF topology (and have more than 1 link), but can't/shouldn't route traffic. That's primarily BGP Route Reflectors, some MPLS/PCE stuff, and VM-hosts hosting/routing previous two things as service. I remember some discussion at an IETF meeting (I think it was @ 93; last time the draft had a presentation slot) whether this is also for taking routers out of service. The result was "no, 6987 / 0xffff remains for that", with the rationale of "if the last path to some prefix is through that router, it should still be reachable, making the problem apparent to an administrator or automated NMS looking at the LSDB / SPF result, without/before causing actual breakage." This is also reflected in RFC 6987's and draft-hbit's introduction sections; 6987 does list disabling a router while draft-hbit doesn't. The two are really quite orthogonal in applicability. -David _______________________________________________ Quagga-dev mailing list Quagga-dev@lists.quagga.net https://lists.quagga.net/mailman/listinfo/quagga-dev
