VLAN and ifInOctets counters Please HELP

[pchivalier]

Is some body should tell me what kind of traffic is counted in MiB II "ifInOctets" for VLAN on switches

Ex:

ifDescr = Vlan 412

ifInOnctets = 42186

Is it the sum of Vlan's interface sum or only the traffic routed of the VLAN

Thanks a lot

Pierre

[Kevin Dorrell]

I cannot answer your question directly, but I did some research, and got some circumstantial evidence that it counts the routed traffic.

The official definition of the OID is found in RFC1213, http://www.ietf.org/rfc/rfc1213 section 6.4.

The object is also mentioned in http://tools.cisco.com/Support/SNMP/do/BrowseOID.do?local=en.

I also looked in the CCIE Fundamentals book, chapter 14 on managing switched networks, but didn't find the answer.

Does this help us? Not really. It does not specifically mention what happens with a virtual interface. But it would seem to imply that it is the total of the octets received.

So I decided to have a look some real layer 2 switches, 4006, 4003, 5500, etc. and found .... that ifInOctets and ifOutOctets were always zero for the virtual interfaces. Since I was looking at layer-2 switches (and I don't have any layer-3 switches) this seems to support the hypothesis that they are related to the layer-3 routing.

Kevin Dorrell

Luxembourg

[pchivalier]

Kevin,

Please let me know if it exist a Mib OID to count VLAN L2 traffic ?

Thanks a lot

Best Regards

Pierre

[Kevin Dorrell]

Pierre,

I don't know of one. The only way I can think of is taking all the individual physical interfaces on the VLAN and adding them up. Not sure what you would do about the trunks either, as the counts on those are across all the VLANs.

I did a search on the SNMP Object Navigator (http://tools.cisco.com/Support/SNMP/do/BrowseOID.do?local=en), but unfortunately I came up with nothing. Sorry.

Kevin Dorrell

Luxembourg

It is hard to imagine how they would implement one. For inter-VLAN traffic, you can just interrogate the router. For intra-VLAN traffic, the processing is more distributed. On the other hand, if you can create intra-VLAN access-lists, so I guess you could have intra-VLAN accounting.