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PRTG Graph on Throughput via SNMP



Good day! I am currently testing my access point (Tp-link TL-WA801ND) to get its actual bandwidth/throughput it can handle. I set up a PC (with prtg and file server) and the AP connected to my switch. I let wireless clients access the AP and download a test file from the file server. What I did was to keep adding wireless clients until the AP can't handle the max load. However, I got a weird graph on prtg with up and down graph. The graph can be shown here: http://postimg.org/image/s4iz4qjgl/ inside the red rectangle. Please help me analyze the graph and what's happening.

Here is the data on the specified time:

Date Time                                              Traffic In (speed)

2/11/2015 3:31:00 PM - 3:32:00 PM          18,212 kbit/s
2/11/2015 3:32:00 PM - 3:33:00 PM          18,286 kbit/s
2/11/2015 3:33:00 PM - 3:34:00 PM          13,134 kbit/s
2/11/2015 3:34:00 PM - 3:35:00 PM          16,754 kbit/s
2/11/2015 3:35:00 PM - 3:36:00 PM          12,572 kbit/s
2/11/2015 3:36:00 PM - 3:37:00 PM          20,296 kbit/s
2/11/2015 3:37:00 PM - 3:38:00 PM          36,224 kbit/s      

Between 3:33 - 3:36, I got up and down graph.

prtg snmp throughput

Created on Feb 12, 2015 3:29:51 AM

Last change on Feb 12, 2015 8:52:07 AM by  Torsten Lindner [Paessler Support]

1 Reply

Accepted Answer




It is a 32 bit SNMP Traffic sensor, so it looks like the drops in traffic are caused by 32 bit counter overflows.

Please check the following article and as outlined there either recreate the sensor as 64 bit sensor or set option "Overflow Values" to "Handle overflow values as valid results": https://kb.paessler.com/en/topic/43503-after-an-update-to-prtg-12-3-the-graphs-of-my-snmp-traffic-sensors-look-scrambled-what-s-up-here#reply-135683

(The article does not fully apply to your issues but the steps outlined are valid here as well)

Created on Feb 13, 2015 2:46:18 PM by  [email protected]

Disclaimer: The information in the Paessler Knowledge Base comes without warranty of any kind. Use at your own risk. Before applying any instructions please exercise proper system administrator housekeeping. You must make sure that a proper backup of all your data is available.