MPLS L3VPN Traffic Seperation

[Marco Lolischkies]

Hallo @ all,

i wanna enable LDP on a device, which is currently only capable for native IP traffic. If i do this, i need to propagte the loopback0 of this device so, that labels are distributed within the backbone. Afterwards, all traffic destined for that loopback will get a label.

That also means that the attached network (they redistributed from BGP) will also have an MPLS label on it. The next-hop (loopback0) is learned from. 

My question is, if there is a way of seperating the traffic, so that some attached networks are routed via IP (without MPLS Label) and the VRF traffic is obviously routed via MPLS? I thought about having another loopback address for the LDP process, but you'll need as well a separate BGP peering for the VPNv4 AFI. I currently don't see any option besides having a kind of VRF lite, separate the traffic via VLAN and bring the VRF traffic on the upstream router into a VRF. But the option doesn't scale that good.

Maybe some of you have some ideas of any other option to solve this.

Regards

Marco

[Masoud Pourshabanian]

I did not test this, just a thought.

In MPLS VPN, usually loopback interfaces are used for the BGP nexthops. It means there must be LSPs for all the loopbacks so you need to configure MPLS IP on the interfaces. It means LDP distributes labels for all the routes in the global routing table.

You can filter LDP labels on the routers. If you only allow labels distribution for loopback interfaces, the routes on the global routing table will not have labels except for loopbacks. It meas routers look up the routing table for global traffic, not the MPLS forwarding table .

Masoud