MibBrowser question


#1

Hello

to check some snmp variable i use the free Tool
ManageEngine MibBrowser

If i select a variable and press line Graph
i have the life traffic (TX) going up and down

but pressing the get snmp variable i do have a value which
go’s up only

so why is this difference?
and how would i got the life traffic as a singel MIB variable?

have a nice day
vinc


#2

Looking at the MIB definition you’ll most probably see that the variable is defined as a counter so the value itself is going up until the highest possible value according to the data type and then wrapping around. The MIB browser calculates the difference to the last value so the graph is going up and down.

Why would anyone want to have the absolute value? Having the value since the start time (or reset) of the network device without knowing how often is has wrapped around since is of no use.


#3

Hello @Wolfgang
yes it is a counter32

iso.3.6.1.4.1.41112.1.6.1.2.1.10.1 = Counter32: 2156213

and no i don’t want the absolute value only this difference to the last value is there a trick to get this difference?

have a nice day
vinc


#4
  1. retrieve the value and remember the timestamp
  2. wait some time
  3. retrieve the value and remember the timestamp
  4. calculate the difference using the four values

#5

@Wolfgang thanks for your feedback
hope somebody could give more Enlightenment
if the check_ is running all 5 to 7 second - faster is not working so what should the delay be between the two value?
at this time have done a
get snmp value
sleep 1
get snmp value
2nd value minus 1value give some result - i think there should be a more smart way to do it.

have a nice day
vinc


(Rafael Voss) #6

You can take a look into interface traffic checks like iftraffic64 and see how these checks are doing it.

My personal experience is, that snmp query intervals < 1m sometimes give really strange results on some devices.


#7

@unic
thanks for your feedback - i will have a look at this plugin maybe i will find some answer to my wish.
my “Interface” i wish to check is the traffic over WLAN
have a nice day
vinc


#8

Looking at the source code of check_snmp you‘ll probably find another way as it supports a check_rate option.


#9

Hello @Wolfgang
Thanks for your feedback
to open the check_snmp with vi give a strange information?ELF^B^A^A^@^@^@^@^@^@^@^@^@^C^@>^@^A^@^@^@à?^@^@^@^

will also check to add this --rate into the snmpget command hope to find some information about that.

have a nice day
vinc


#10

check_snmp is a binary. Looking at the source code in the monitoring-plugins.org repository might help.