Hello Everyone!
I'd like to share with you with the problem that I've encountered regard SNMP interface traffic monitoring on Cisco Nexus 3500 devices.
We are transfering our network infrastructure into the Nexuses and we encountered a problem with interface traffic bitrate monitoring on Nexus 3548: SNMP ifHCOutOctets and ifHCInOctets counter's deltas don't show valid data.
We've been investigating this problem and figured out that it could be related with refresh rate of that counters.
I've measured, by snmpwalk, the time between single increments of ifHCInOctets counter for VLAN Interface and it apears to be about 140seconds. But for physical interfaces (Eth) the SNMP interface counters interval are about 15sec and with sample rate 60s for queries we still can observe the problems on graphs (see attached screnshot).
We get the same results when testing the issue on different physical devices (Nexuses 3548) on different software versions - including the latest one.
And for Ethernet interfaces (same NMS- ZABBIX- config):
We have tested a wide range of Cisco IOS devices and Huawei s6700 switches and there were no such problems.
The main problem is that we cannot monitor our crucial, nexus devices, via SNMP (as you can see on attached graphs). Results are the same when we configure Cacti or Zabbix to monitor Nexus devices.
The results of such monitoring do not have meritorical value or use.
We are working on this case with Cisco TAC, and they manage to reproduce the issue in their LAB environment. But for now, they cannot provide any solution and they claim that this is not a bug. If we get any final statement for this case I will post it here for your information.
I will be more than glad if you can post any ideas that help me resolve described issue.
Thank you in advance!
Michal
