8/3/2023 0 Comments N66u website monitor![]() ![]() I already listed most of these “raw” measure OIDs in the beginning, but what is a raw value and how do I use them?Īfter some Google-fu (or flu) it turns out the “raw” values are something called CPU ticks. However, somewhere on the mighty internet I did find information that the average value OIDs (1-15min) would be deprecated because the same information can be derived using the “raw” values. So is there another way I can get a finer granularity of information somehow? Looking and asking around a bit I did not find much information on this. However, as before, this is obviously not as fine grained as I was hoping. Using this, I get a load graph that is the opposite of the idle graph, so obviously it is now correctly measuring the load average over the same period as the idle graph is: ![]() The value (INTEGER:1) is the load of the processor. 1.3.6.1.2.1.25.3.3.1.2Īnd on another AC68U that I also had access to it also gives another core with id 196609 (the AC68U is a dual-core router). To find this out I do an snmpwalk on commandline: This one is a bit odd though, I believe the “x” part identifies the processor for which I want the statistics for (in this case my router only has one core, in more modern ones there are multiple). However, obviously I would prefer something more fine-grained.Īnother hopeful approach I found is the OID for something called ProcessorLoad (.1.3.6.1.2.1.25.3.3.1.2.x). Even though my “system+user” measure is obviously broken, I could get the CPU load from this by using a formula of “100 – idle”. However, it is much less “bumpy” than the router graph, meaning it is an average over a longer period than the one shown in the router interface. The admin interface shows a shorter timeframe, so the right hand side of the SNMP idle graph matches generally the slope of CPU load shown in the router admin interface. Also, the idle graph might be correct but it is definitely not “real-time”. When I look at the CPU load graph shown in the router admin interface itself, this is quite obvious: So I am missing a large chunk of actual CPU load somewhere (about 23% in the right side here). Obviously not, as the idle time shows going down by about 25% on the right end, while the system+user loads sum up to less than 2%. I was expecting system+user CPU time to equal to what would be the actual CPU load. So I set up my system to query these from the router: That is, load percentage at the time of measurement. Anyway, I hopefully assumed it was “real-time” percentage. That is, percentage over what time? Or I am sure it is said somewhere but I did not stumble onto it. However, even though these are listed the same way all over the internet, nowhere does it really say what is their granularity. The percentage values seemed much more interesting. Averages of 1-15 minutes are then not very useful for me. So, looking at these, I figured if I wanted to figure out why my client-server performance gets hit when running the performance tests over the router with high numbers of concurrent clients, I would want a very fine granularity of information on the CPU load. So for me, I just Googled for “SNMP CPU OID” etc. These are listed in something called MIB (Management Information Base) files, which there are plenty of, and browsing these gets complicated to try to find what you are interested in. An OID is an Object ID that uniquely identifies some property we want to monitor/manage with SNMP. Secondly, I needed to find the OID’s to monitor. The SNMP communities set on this panel are by default “public” for the reading operations and “private” for the write operations. Of course, I had done this long time ago, but anyway, on this particular router this is done in the admin panel under Administration->SNMP. I will just document my experiments in relation to setting up the CPU monitoring here for whatever that’s worth.įirst off, I needed to enable SNMP on the router. Somehow this did not turn out to be quite so simple. However, this time I was trying to monitor the router CPU load and bandwidth use to figure out if delays in my performance tests were somehow related to the router performance (as illustrated in some previous posts). You know, just your regular paranoid stuff. I noticed I have previously also tried to monitor my ASUS RT-N66U router to see what traffic passes through. ![]()
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