Hi Laurent,
Devices typically update their mib counters every 2-3 seconds and OneClick will display the information approximately every 10 seconds so in a normal situation this should not happen.
However if you want to debug this further we can do this by selecting a single port that has this behaviour.
1. Using CLI, send the 0x10297 action to the port(s) in the list:
./update action=0x10297 mh= <port mh>
This will enable debugging for the port for a period of 7 days after which Spectrum will automatically disable the debugging.
2. When the problem is seen again navigate to the port in question and select the events tab. Export all events to a CSV format for the timeframe where the issue occurred. Staring 5 minutes before and 5 minutes after is a good timeframe.
3. Examine the event report in MS excel. In the case above (a saw-tooth patterned graph with lows that are zero), the key is to look for and examine instances of the 0x00010d81 event where the “CURRENT LOAD_TOTAL” value is zero. Each of these will correspond to a low of zero in the graph.
4. For each particular instance (event 0x00010d81 with “CURRENT LOAD_TOTAL” equal to zero), the next step is to look at the data to see if the “Initial” and “Final” values for the major octet and packet rate counters are the same – which means their delta is zero over the sample period. Pay specific attention to looking at the differences between the “Initial” and “Final values of the following:
X_IN_OCTETS and X_OUT_OCTETS
X_IN_NUCAST_PKTS and X_OUT_NUCAST_PKTS
X_IN_MCAST_PKTS and X_OUT_MCAST_PKTS
X_IN_BCAST_PKTS and X_OUT_BCAST_PKTS
X_IN_UCAST_PKTS and X_OUT_UCAST_PKTS
If all of the above counters show a zero delta over the sample period then the device is not updating its MIB counters often enough. Spectrum will poll the source data for the graph every ~10 seconds and, if the device is slow to update its counters, this will manifest as a saw-tooth graph with lows of zero, and highs that are typically less than 100%. Devices typically update their MIB values once every 2-3 seconds and a longer update interval implies a problem with the MIB agent on the device. The specific MIB counters Spectrum is reading can be obtained from the “EXTERNAL SOURCE ATTRIBUTES”. This list contains the attribute IDs of all the external attributes spectrum is reading for port performance calculations for the port in question. With this information can check for yourself by using a sniffer trace to verify the agent behavior while the Spectrum Performance graph is open.
If you have any further questions you can provide the debug data in a support issue for us to investigate further.
Best regards,
Glenn