Some device charts showing Interface bits-in/out traffic intermittently have gaps in data. Why does this occur?
Sometimes, this can be a problem with the devices themselves. If there are many warning messages in the DC logs where it was not able to contact or poll the device/s due to timeout:
Or if there are instances where a 32bit counter has rolled over:
The metric in this case is IfInOctets (OID=). This is a 32-bit counter.
So when the value becomes too large for a 32 bit counter to hold, the counter rolls back to 0 and starts again, meaning the poll is dropped.
DX NetOps CAPM all releases
The device may not actually be supported in CAPM. You can check this on our Certification portal:
However, it maybe closely related to other devices that are certified with many of the same OIDs and MIB structure. In this case CAPM is able to discover it and associate Metric Families to it, but since it's not accurately fully certified, it is only using the 32 bit counters (default) of the Interface Vendor Certification instead of the 64 bit in High Speed Interface VC.
So, without proper certification, CAPM uses 32 bit counters with the resulting counter rollover errors such as the following that cause dropped polls (which appear as data gaps):
The only way to overcome this without certification is to use fast polling, as per:
We have another KB article that advises further on how to address these sorts of issues: