SNMP returns strange "bits sent/received" values on a particular port, why?

Question

I have a HP V1910 Switch in my office. I have set up monitoring via SNMP on my local Zabbix server, and everything looks really good on almost all ports (for example, when I use iperf to test throughput or just send a big file between 2 machines connected to 2 different ports).

There is one port though that gives me very odd (too low) figures on incoming and outgoing traffic, even though it gets plenty of traffic, my local PoE Switch (UniFi Switch 8 POE-150W): https://www.ubnt.com/unifi-switching/unifi-switch-8-150w/

The latter is sending all the traffic that goes to the wi-fi access points. We have a lot of users connected via wi-fi, so 20Kbps simply does not make sense.

What I really want to do is monitor the traffic on this port, so I've set up SNMP on the UniFi switch in question as well, but it's not exactly the same.

Any advice? Could it be that when 2 switches are interconnected in this way the port starts behaving in a special way? Everything has a very default configuration, no VLANs.

Thanks

Answer 1

Embarrassingly enough, this is was not an issue with the switch or with networking.

The problem was bad cabling (confusion regarding which cable goes where) and that Zabbix was configured to make SNMP-checks every 180 seconds, so short peaks in incoming/outgoing packets were simply missed many times, as a typical iperf-test takes 10 seconds. Once I had made Zabbix do the SNMP-checks every 30 seconds I could match the traffic on a port with another graph and see that the cables were messed up. Kind of like this: