unnecessary and frequency kernel routing update

[Ondrej Zajicek]

On Mon, Apr 29, 2013 at 10:41:24PM +0400, Slawa Olhovchenkov wrote:
> > If the received route update is exactly the same, then it should
> > be ignored and not propagated further, but there is probably some
> > minor change (like in BGP attributes) that forces the propagation.
> 
> How I can see in debug log whats chnged?

There is no easy way, either you could put print commands to
import/export filters for specific route attributes (like bgp_path), 
or you coud try to catch it interactively by 'show route all'.

> > BIRD currently does not support anything that could prevent propagation
> > of frequent updates.
> 
> I thinks this is useful feature.

Yes, but problematic to implement in the current design.

> > For the kernel protocol it could be hacked by removing the code that
> > handles route updates and depending just on periodic routing table scans
> > for BIRD-kernel routing table synchronization.
> 
> This is bad point. For external BGP update this semi-reasonably, but
> for OSPF/etc this is unacceptable.

Well, for OSPF such problem cannot happen, as OSPF recalculates routes
at most once per second. But it is true that it is a hack.

-- 
Elen sila lumenn' omentielvo

Ondrej 'SanTiago' Zajicek (email: santiago at 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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