Page 1 of 3
ifspeed - cisco router
Posted: Tue Sep 24, 2013 6:52 am
by joehamm
our cisco router is reporting its ifspeed at 4.29Gbs - while this may be accurate, the circuit is only 1Gbs
I have been unable to find where to change this so that our utilization graph reports correctly relative to the circuit
I would expect that there would be a file or db entry that I could modify
Any direction would be appreciated
Thanks in advance
Re: ifspeed - cisco router
Posted: Tue Sep 24, 2013 9:21 am
by abrist
Is that speed reported through snmp?
Re: ifspeed - cisco router
Posted: Tue Sep 24, 2013 9:58 am
by joehamm
yes, ifspeed is reported via SNMP
Nagios, when I run a monitoring wizard collects the interface ifspeed for all interfaces on the device
it just happens that the Cisco reports the information incorrectly
Re: ifspeed - cisco router
Posted: Tue Sep 24, 2013 10:09 am
by abrist
You would need to alter the mrtg entries for this port. or remove the port from your mrtg file and re-add it through the wizard, altering the speed. Do note: doing this will most likely skew the speed reports and you will most likely lose any historical data collected up to this point.
http://assets.nagios.com/downloads/nagi ... Router.pdf
Re: ifspeed - cisco router
Posted: Tue Sep 24, 2013 10:31 am
by joehamm
i have no issue giving up the data to this point as it is incorrect
however the procedure you provided - I don't believe will help me
when I rediscover the device - it still queries the MIB OID via SNMP and gets the wrong port speed again
during the monitor wizard - I do not have the ability to modify the ifspeed - would have already done so if I could have
so I need to modify after the fact
the value has to be stored somewhere because calculations are performed using the information
I don't believe it to be the mrtg files as that appears to have the threshold values for alerts - not the ifspeed
Re: ifspeed - cisco router
Posted: Tue Sep 24, 2013 1:10 pm
by abrist
There are only two places that could contain this information - the check command (or plugin), and the mrtg configuration. The switch and router wizard should give you the option of changing what you want to set as warning/critical. The ifspeed is just the max cap. You should still receive metrics in bit/bytes.
The check only includes the the thresholds, so the proper place to look, *is* the /etc/mrtg/mrtg.cfg file. Each interface should include a MaxBytes Directive, lik:
This is the value you most probably want to change. Do understand that you may need to remove the RRD and XML perfdata associated with this check to get them to regenerate with the correct values.
Re: ifspeed - cisco router
Posted: Tue Sep 24, 2013 1:45 pm
by joehamm
abrist wrote:There are only two places that could contain this information - the check command (or plugin), and the mrtg configuration. The switch and router wizard should give you the option of changing what you want to set as warning/critical. The ifspeed is just the max cap. You should still receive metrics in bit/bytes.
The check only includes the the thresholds, so the proper place to look, *is* the /etc/mrtg/mrtg.cfg file. Each interface should include a MaxBytes Directive, lik:
This is the value you most probably want to change. Do understand that you may need to remove the RRD and XML perfdata associated with this check to get them to regenerate with the correct values.
it does give the option of changing the warning/critical - except that that is irrelevant when the value used for ifspeed is incorrect - the ifspeed is not able to be changed
also warning/critical can be changed later in gui - also note that these are in % - so if i set a threshold of 50% based on a 1 gig circuit - i would be looking for 500 Mbs - but as the calculation for the utilization is based on ifspeed.... which is set to 4.29 Gbs - my alerts would not trigger until I hit 2.14Gbs - sure I could play with it so it alerts at whatever I want but it would be much simpler to reset the value for ifspeed
plus, the data provided is also off - any utilization graph is meaningless to any typical user who doesn't know it is wrong
MaxBytes is thresholds for alerts
and as i mentioned earlier - i have no issue completely removing the device and all data files related to it - they are all meaningless at this time as they are incorrect as they are based on the incorrect ifspeed value
the only place I have seen anything so far that I believe could be changed is the mysql DB and as I inherited this system - I do not have write access - just about ready to blow the entire build away - at least then I could try and modify the mysql but had hoped that Nagios was more easily updated - inaccurate MIB values are not so uncommon that we should not be able to update them
Re: ifspeed - cisco router
Posted: Tue Sep 24, 2013 2:00 pm
by abrist
joehamm wrote:MaxBytes is thresholds for alerts
Let me quote this:
MaxBytes
The maximum value either of the two variables monitored are allowed to reach. For monitoring router traffic this is normally the bytes per second this interface port can carry.
If a number higher than MaxBytes is returned, it is ignored. Also read the section on AbsMax for further info. The MaxBytes value is also used in calculating the Y range for unscaled graphs (see the section on Unscaled).
Since most links are rated in bits per second, you need to divide their maximum bandwidth (in bits) by eight (8) in order to get bytes per second. This is very important to make your unscaled graphs display realistic information. T1 = 193000, 56K = 7000, 10 MB Ethernet = 1250000, 100 MB Ethernet = 12500000. The MaxBytes value will be used by mrtg to decide whether it got a valid response from the router.
If you need two different MaxBytes values for the two monitored variables, you can use MaxBytes1 and MaxBytes2 instead of MaxBytes.
Example:
MaxBytes[myrouter]: 1250000
http://oss.oetiker.ch/mrtg/doc/mrtg-reference.en.html
Changing the SQL will not help. The sql only includes the check information:
Code: Select all
$USER1$/check_rrdtraf -f /var/lib/mrtg/$ARG1$ -w $ARG2$ -c $ARG3$ -l $ARG4$
Where:
Code: Select all
$ARG1$ is the rrd file.
$ARG2$ is warning
$ARG3$ is critical
$ARG4$ is display label.
Again, what you need to do is:
1. Change the mrtg "MaxBytes" information
2. Remove the relevant rrd from /var/lib/mrtg
3. Remove the relevant rrd and xml from /usr/local/nagios/share/perfdata/<hostname>/
4. And then wait for two checks time.
The values that you want to change, can only be done in the RRD. The rrd gets generated from the mrtg rrd and subsequently the mrtg config. . . .
Re: ifspeed - cisco router
Posted: Tue Sep 24, 2013 2:03 pm
by BanditBBS
I have to jump in here. Setting port speed is an option during the wizard, in two spots.
First on the initial screen:
1.JPG
Then on the screen after it finds all your ports:
2.JPG
if it doesn't show the proper speed on the second screen, like mine shows 100.00Mbps, then I am afraid that is a switch issue and not sure it can be resolved.
EDIT: I worded that wrong. You can only set the default speed on first page. The second page just shows you what is discovered and the w and c ranges. Sorry for confusion. Original statement is still true I believe. If not detected properly, I believe it is a switch issue and one I have never seen before.
Re: ifspeed - cisco router
Posted: Tue Sep 24, 2013 2:26 pm
by abrist
Thanks for the help Jim.
Joe: let us know how this works out for you.