Solved: SNMP VLAN traffic

misd.network.support · ‎07-08-2008

Hi all,

Is it possible to graph (MRTG or similar) all traffic passing in and out of a VLAN. I have tried graphing the VLAN interface on a MLS that acts as the default gateway for that VLAN (ifdescr = Vlan180 for example), however, the traffic I see is a couple of hundred bytes per second - which is far too low. Am I missing something?

Apologies for post in the LAN section too - I couldn't work out how to move my post.

Cheers,

Ben

Joe Clarke · ‎07-08-2008

The counters for the VLAN interface will only reflect the traffic destined for the switch. In order to get the actual transit traffic on a 3750 you would need to either SPAN the VLAN traffic to a monitor port, or sum the counters from the ports which are a member of that VLAN.

View solution in original post

Joe Clarke · ‎07-08-2008

What type of device is this? You might have better luck polling the cseL3VlanInOctets and cseL3VlanOutOctets from the CISCO-SWITCH-ENGINE-MIB if you need hardware stats from Cat6500s.

misd.network.support · ‎07-08-2008

Its a C3750G-12S

Cheers,

Ben

Joe Clarke · ‎07-08-2008

The counters for the VLAN interface will only reflect the traffic destined for the switch. In order to get the actual transit traffic on a 3750 you would need to either SPAN the VLAN traffic to a monitor port, or sum the counters from the ports which are a member of that VLAN.

misd.network.support · ‎07-08-2008

jclarke - Thanks for the info. Can you advise - does running SPAN for a VLAN have significant impact on CPU or backplane usage?

Cheers,

Ben