[mrtg] Re: Ambiguous graphs

[Alex van den Bogaerdt]

On Fri, Sep 13, 2002 at 12:05:16PM +0530, Vaibhav Bawa wrote:

> I'm attaching a gif image that shows the traffic activity of a 1.544 Mbps
> link. In this case I've also enabled Threshold checks on Incoming traffic so
> that when there is 'zero %' Incoming traffic, a script runs that informs the
> concerned that the link has become inoperational. But the graphs show
> Outgoing traffic activity, even when the Incoming traffic is 'zero %'. 

When I see "Current  In:      640.0 b/s", I don't think of this as
link down ...

0.0% is a rounded percentage (or is it truncated? dunno).  This doesn't
mean the link is down.

> Anyone will assume that if the link were down, both Incoming and Outgoing
> traffic would become 'zero %'. I wonder if MRTG is actually giving a true
> picture of the link status in my case. Any ideas?

MRTG is giving a true picture of what you ask it to do.  You ask it
to monitor traffic, not link status.

Also, yes: I think the percentage will become zero if the link is down.
This doesn't work the other way around.  No traffic does not mean no link.

For link status and alarms, use a suitable tool.  Don't use your
screwdriver as a hammer.

Alex

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