[c-nsp] Traffic stats on SVIs

[Seth Mattinen]

Jee Kay wrote:
> I have an interface on which I receive a number of tagged VLANs that
> fan out to various customers. Each VLAN is essentially switch-local,
> carrying a /31 and an SVI as a point-to-point link from the CPE to our
> PE.
> 
> I poll each SVI for traffic stats to see how much bandwidth individual
> customers are using on the link, as well as polling the interface
> itself to see how much aggregate bandwidth is being used. The problem
> I have is that the SVI traffic statistics appear to now be showing the
> traffic being routed through it.
> 
> Specifically, the sum of all the SVI traffic added up doesn't even
> come close to the actual traffic being observed on the aggregate
> interface. It does show some which appears, from the regularity and
> bandwidth used, to be OSPF traffic going between the PE and CPE boxes.
> What it doesn't appear to show is any transit traffic at all.
> 
> Am I doing something drastically wrong in assuming that the SVI
> traffic stats should also show transit traffic going through that SVI?
> 
> I've checked every VLAN being accepted on that interface to make sure
> there isn't some traffic being switched that could account for the
> difference; there isn't. Additionally I know at least 1 of the VLANs
> is carrying a bit of traffic in excess of OSPF (I also poll the
> equipment at the other end) and the only way that traffic can get to
> us is via that SVI :)
> 

The SVI counters are only showing software switched traffic; anything 
switched in hardware won't appear.

-- 
sethm at rollernet.us
Ne cede malis sed contra audentior ito