Detecting link state, FreeBSD

Ondrej Zajicek santiago at
Tue Nov 2 21:56:15 CET 2010

On Tue, Nov 02, 2010 at 11:00:39AM -0700, Mahlon E. Smith wrote:
> I'm running bird 1.2.4 on a series of FreeBSD OSPF routers.
> Had a backhoe go through some fiber this morning (really), and was
> surprised to find that bird didn't update routes automatically.
> I don't see anything else to add or modify in the config for checking
> interface status -- did I miss something?  My anticipated behavior would
> be that a link down would perform a route update. 


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. Drawback of HELLO
protocol (to check reachability) is that it has some timeout to find
out that the neighbor became unreachable. By default, it is ~ 40
seconds, But it is possible to configure it to < 10 seconds (see
hello/wait/dead interface options).

Elen sila lumenn' omentielvo

Ondrej 'SanTiago' Zajicek (email: santiago at
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3,
"To err is human -- to blame it on a computer is even more so."
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