I want to monitor the incoming and outgoing traffic of an lacp trunk (Port 23 and 24 (group id 02)).

How can I get the value? I already searched for an OID, but I have not found it.

Before, I used the following OIDs:

  • IfOutOctets:[PORT]
  • IfInOctets:[PORT]

But these are only for a single port.

Switch: 3com Baseline Switch 2924 SFP Plus

Result of GetIf:

enter image description here

  • 1
    Have you done a SNMPwalk or used GetIf to find the ports and OIDs in question? Commented Aug 18, 2014 at 6:50
  • GetIf is a very interesting tool. Thanks for that :). This is a 24 Port Switch. But the interfaces shown in this tool goes up to 32. (See my added screenshot above). Why? 25-32 seems to be the same physical device
    – Vince
    Commented Aug 18, 2014 at 7:03
  • Your SFP ports are probably interface 25-26 which show a speed > 0. Interfaces 27-32 are some sort of internal virtual interface. If you have subinterfaces for example for VLAN tagging, that could be one explanation, but I'm speculating here. Commented Aug 18, 2014 at 9:11
  • Yes, that was my guess too. I just tried it with a newer Switch (HP). There I get an interface description named Trk1, Trk2 etc.. It works fine. It's only the 3com switch, which makes me annoyed ;)
    – Vince
    Commented Aug 18, 2014 at 9:46

1 Answer 1


Your SNMP index may not match your port number. On some platforms, the indexes are not even persistent across reloads unless configured to be. I'd expect to find an interface speed of 2Gbps in your SNMPwalk for your 2-port LACP. You should scrutinize any ports showing a speed > 0 besides your physical ports 1-24 as possibly the LACP virtual interface.

I'd recommend investing some time to install and learn Cacti. Cacti excels at SNMP monitoring especially using the standard RFC IF-MIB. You can enable debugging when Cacti queries your platform which will correlate other helpful elements of your ports like descriptions. Keep in mind that your SNMP counters for your VLAN interface may only count octets going into and out of the VLAN, not within the VLAN.

  • 2
    And, if there is no SNMP index for these aggregated port, you can always make a combined graph of all the members of the port. This will have the added bonus of making the load-balancing visible.
    – JelmerS
    Commented Aug 18, 2014 at 8:45
  • @JelmerS Yes, that would be a good alternative.
    – Vince
    Commented Aug 18, 2014 at 9:47
  • I tried it with Ports 27-32. Only the interfaces 25 & 26 are showing a value > 0. The highest value is 876349763. But that is still too low. So I think I have to change to Cacti.
    – Vince
    Commented Aug 18, 2014 at 9:51

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.