IOS XR SNMP monitor graph unstable

[jngjng42]

hello.

I am using PRTG to monitor router ASR9910.

The SNMP interface sensor traffic graph appears zigzagging.
The scan interval is also set to 1 minute.
I heard that some people solved the problem with ifmib cache, so I applied it, but the graph remains zigzag.

If you know a solution, please share.

[Ruben Cocheno]

@jngjng42 

Found a few bugs related to the ifmib cache, but when polling is lower than what you using. Probably updating MIBS on PRTG?

[tkarnani]

https://community.cisco.com/t5/service-providers-knowledge-base/asr9000-xr-understanding-snmp-and-troubleshooting/ta-p/3144621

ifmib stats cache; it collects all the data from all the interfaces every 30 seconds

the issue is that when you poll every minute, it doesn't refresh the stats cache. this cache timer is independent.

for example

poll 1: stats cache just refreshed 0 seconds; accurate if counters

poll 2: stats cache 25 seconds old ; traffic dip

poll 3: stats cache 3 seconds old; traffic spike

this internal timer is not tracked with snmp and can give the impression of a microburst