Netflow Support for MPLS L3VPN

[Tim K]

I would like to know if there is a way on a P router to view the VPN traffic that is flowing through an interface. I have enabled Flexible NetFlow on the interface in both the ingress and egress direction, however, the only Netflow that is being captured is the underlay traffic (LDP, OSPF, BGP). Does anyone know how to view the details of the traffic ingressing or egressing a P router?

Thanks so much!

[Giuseppe Larosa]

Hello Tim,

a P router performs label swap of the external MPLS label  and it is not able to discriminate IPv4 traffic with next-hop the remote PE loopback address from MPLS L3 VPN that has the same next hop the remote PE loopback address.

Looking at show mpls forwarding you can get byte counters for each LSP per IP destination but it is an aggregate of all traffic exchanged over the LSP regardless of the type of service ( simple IPv4 with BGP, MPLS L3VPN, an EoMPLS pseudowire or a VPLS pseudowire.

So I don't think you can get L3 VPN info on a P node.

You can get this info on the ingress PE node and on the egress PE node.

Hope to help

Giuseppe

[Tim K]

Thank you for the reply Guiseppe. How would I go about getting the information on the ingress PE router? I have a PE router that has 3 interfaces to other P routers. I would like to get an idea of what customer traffic is going down what interfaces. I can see which way the router routes to the distant PE router. However, I haven't been able to use Netflow (or something else) to see the specifics of what goes down those P-facing interfaces.

[Giuseppe Larosa]

Hello @Tim K ,

on the CLI you can use

show mpls forwarding <remote-PE-loopback-address>

The VRF aware Netflow feature is to be configured on  VRF CE facing interfaces where the router receives and sends IP packets.

At least so it was intended at the beginning when the feature was introduced.

Hope to help

Giuseppe