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why do i get "no data" in sensor fatory when the difference of the 2 channels used is close to zero

Votes:

0

I belong to a french Telecom Company (SAGEMCOM) We are evaluating your product for traffic analysis of an Operator Telecommunication Network. we are using the free edition of the version 8 (limited to 10 sensors) the last one (PRTG Network Monitor 8.2.0.1897)

During our tests: we have defined 2 "snmpcustomsensor" using the OID value one on one device on the Ingress traffic (Channel(2005,0)) the other on another device on the Egress traffic (Channel(2003,0)) these sensors are defined as delta(counters) We get data for these sensors;no problem it's ok

We have decided to define a sensor factory to get the graph which will show the difference between ingress and egress traffic. like this:

#1:Diff Ingress-Egress
((Channel(2005,0)-Channel(2003,0)))
#2:Ingress
Channel(2005,0)
#3:Egress
-Channel(2003,0)

When we validate it, we got all the values for #2 and #3 (for this it's OK)
But for #1 we got 4 values when it was created and since then "nodata" Remark1: the values for #1 are closed to zero Remark2: if we define #1 this way (2*Channel(2005,0)-Channel(2003,0)), then its OK

Can you explain why? Is it a bug or is there away to make it work? Thanks for your help

channel difference prtg8 sensor-factory snmp sum

Created on Jan 19, 2011 2:45:56 PM

Last change on Jan 20, 2011 2:05:24 PM by Torsten Lindner [Paessler Support]



4 Replies

Votes:

0

Hello,

unfortunately we can't explain this. Can you test if changing the formula and saving this change (to the following example) which results this brings:

#1:Diff Ingress-Egress
((Channel(2005,0)-Channel(2003,0)))+1
#2:Ingress
Channel(2005,0)
#3:Egress
-Channel(2003,0)

Does this show all values from the past, but now new calculations are made?

Best Regards.

Created on Jan 20, 2011 2:33:39 PM by Torsten Lindner [Paessler Support]



Votes:

0

Hello, thanks for your help I have tried it but it doesn't change anything few values then ...nothing. Do you plan to investigate this problem? It's easy to reproduce: just make the difference between two different counters which have nearly the same value (ie: the difference is closed to zero) We have planned to buy an unlimited license for managing an "snmp devices" operator telecommunication network ... And this feature in a key point for us best regards D.Goret

Created on Jan 21, 2011 2:39:38 PM



Votes:

0

Hello,

we are already investigating this problem (1. We asked you to try something. 2. We tried to reproduce the problem ourselves in our lab, which showed -unfortunately- no problems).
Can you please be specific, when you changed the formula, did it then afterwards show all values (from the past) until the point when the change was made? But then no new values were calculated anymore? Is this correct?

Best Regards.

Created on Jan 24, 2011 1:29:04 PM by Torsten Lindner [Paessler Support]

Last change on Aug 26, 2015 12:38:38 PM by Luciano Lingnau [Paessler]



Votes:

0

Hi, In fact when we change the formula, the result was the same as previous it shows few values in the past (not all of them...) and then nothing. Is there a way for me to send you screen capture on what I get. Best Regards Dominique

Created on Jan 25, 2011 7:49:03 AM




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