[c-nsp] deactivate line with too many packet drops?

[Gert Doering]

Hi,

On Mon, Sep 26, 2005 at 08:35:55AM +0200, oboehmer at cisco.com wrote:
> > is there a way (e.g. using BFD, or some other magic smoke) to
> > deactivate a line that has more than "x" percent packet loss?
> 
> in theory, there is PPP LQM (RFC1989) which measures packets
> sent+received (IOS cmd "ppp quality <percentage>"), 

Oh?  Didn't know that.  Thanks for pointing it out.

(Doesn't help in this specific situation, as the link is GigEthernet, and
no PPP involved, but I've seen similar issues on serial links before)

Is the algorithm that IOS uses to decide to take a link down & to take
it back up (that's the more tricky part...) documented?

> but there are hardly
> any customers using this feature. Not sure why, but maybe they rather
> want to make this decision manually using appropriate alarm functions in
> their NMS.

In the specific case we had this weekend, there weren't any NMS alarms - 
we trigger on "too many input errors in a given time frame", and the
packets just disappeared, no input errors at all.

Time to start thinking about setting up & monitoring SAA probes for
links with specific non-trivial failure modes...

gert
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Gert Doering - Munich, Germany                             gert at greenie.muc.de
fax: +49-89-35655025                        gert at net.informatik.tu-muenchen.de