traffic statistics on vlan interface

[ravisambaji]

Hi ,

I have 7600s in my network. The traffic statistics on my SVI interface doesn't corresponds to the traffic respective to physical ports. Assume i have four physical ports with access vlan 100. The traffic on interface vlan100 should be sum of traffic on all ports ? but it is not. It doesn't match. Customer wants to use the stat on vlan interface to monitor the traffic, however the traffic stat is not valid.

Any help is appreciated.

Regards

Ravi

[Ruchir Jain]

Hi Ravi,

The traffic rate on interface vlan would only correspond to the traffic that would be routed. Any locally switched traffic that is coming in vlan 100 and going out vlan 100 would not be reflected on the interface vlan.

Also, if you have multicast traffic going out of vlan 100 and let us say it goes out of 4 ports of vlan 100. In this case also the traffic would be counted only once on vlan 100 as it was routed once though it was counted 4 times on physical interface, once on each physical port.

Moreover, physical interface (if a trunk) would always have slightly high rate than interface vlan because of the extra dot1q header and other layer 2 protocols.

I hope this helps.

/Ruchir

[judebryant]

I have 7609 routers.

I use a program called Zenoss and it maps not only interfaces, which includes SVIs.  It also will map each individual service instance mapped to a specific port.

You might look into this program

Regards

Jude Bryant

Network Admin

Pioneer Telephone