[c-nsp] Traffic stats on SVIs

[Jee Kay]

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 :)

Thanks,
Ras