vlan counters with snmp

[mskrzypczak]

Hi,

Could anyone tell me how to access VLANxx counters (OIDs for InOctets and OutOctets) on Catalyst WS-C6506 with SNMP? Unfortunately, I've failed with finding solution on my own.

Mirek

[sstudsdahl]

Mirek,

You can use the same OID's that you would for a physical interface located in the IF-MIB. Here are the OID's that you can use:

ifInOctets = 1.3.6.1.2.1.2.2.1.10

ifOutOctets = 1.3.6.1.2.1.2.2.1.16

You may want to look at the SNMPv2 OID's instead as they won't roll so quickly on a high utilization link. They are also located in the IF-MIB and are:

ifHCInOctets = 1.3.6.1.2.1.31.1.1.1.6

ifHCOutOctets = 1.3.6.1.2.1.31.1.1.1.10

All that being said, the information that is returned won't reflect the amount of data truly being sent though the switch. By default a Catalyst 6500 will be set for Multi Layer Switching. This will send the first packet in a flow to the MSFC, hitting the VLAN interface, and all subsequent packets will then be switched at layer 2, not touching the MSFC/VLAN interfaces. Here is a link for more information about MLS. http://www.cisco.com/warp/public/473/35.html

For a true depiction of the traffic that is flowing through the 6506, I would monitor the phyisical interfaces of the switch and not the virtual (VLAN) interfaces.

Steve

[mskrzypczak]

Hi,

Unfortunately these counters seems to be empty (0). I've asked about OIDs because now I'm doing that in maybe not very elegant way (also a bit uncomfortable) - using telnet, show vlan counters and cutting out values of L3-In/Out-Unicast-Octets.

Mirek