On Wed, Nov 03, 2010 at 07:39:48AM -0700, Mahlon E. Smith wrote: > On Tue, Nov 02, 2010, Ondrej Zajicek wrote: > > > BIRD currently does not check or use link up/down state. OSPF routers > > generally check reachability using HELLO packets, not by reported link > > state, although sometimes this is also implemented. > > Hmm, in this particular case, bird is currently responsible for managing > routes that go out through that interface. (Used for internet failover, > on the external interface.) With the link state down, the OSPF daemon > was still reachable to the internal network, so the HELLO check doesn't > help me unless the /internal/ interface dies, or the entire router does.
Although i agree with Joakim Tjernlund and others that link state change detection is useful to get faster response to internal network unreachability. I think that in your case you would need something slightly different. I understand that you have some (probably static) routes with gateway accessible through given (external) interface and you want to detect unreachability of the (external) gateway to add/remove that (static) routes. Detecting a link state is crude, because there might be many other kinds of problems that does not change link state. I would suggest to use some shell/perl script that ping to the gateway and according to its reachability it will enable/disable static protocol (with routes using that gateway) in BIRD. I plan to implement a link state change handling, but it will take some time, it is definitely more complicated than the patch you sent (for example, it should differentiate between administrative up/down and link state up/down). -- Elen sila lumenn' omentielvo Ondrej 'SanTiago' Zajicek (email: santi...@crfreenet.org) OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net) "To err is human -- to blame it on a computer is even more so."
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