On Tue, Aug 25, 2015 at 11:18:34PM +0200, Toke Høiland-Jørgensen wrote:
> So what events cause a neighbour to go away / come back as far as the
> bird core is concerned? Is it just the obvious case of the interface
> going up/down and gaining or losing addresses? Or is there something
> smarter?

Yes, just interface or prefix up/down events and link change events.

There are two common usages for neighbors:

Persistent (NEF_STICKY) neighbors are used by protocols that do not
generally process iface/prefix events because they just care about some
explicit addresses (e.g. BGP for the configured address of the peer).

Regular neighbors are used by protocols just for validation that IP
address is valid and associated with given iface (or finding the
associated iface). In that case a neighbor is requested but not kept
(ptr not stored in structures) and neighbor hooks are not used. See
rt_sync() in OSPF or advertise_entry() in the old RIP code.

-- 
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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