How it Works
This section briefly describes how the MPLS Support for UPF works.
In the current architecture, VPP forwarder provides its own MPLS stack, which supports all the existing functionalities for MPLS packet processing. The VPP MPLS stack is configured with the appropriate FTN (FEC To NHLFE) and incoming label map (ILM) tables. This generates the MPLS packet on the egress with the correct MPLS header. It also processes the incoming MPLS packet and switches the packet based on the incoming label to the appropriate VRF table.
VPC-SI also supports VPNv6 as described in RFC 4659 – BGP-MPLS IP Virtual Private Network (VPN) Extension for IPv6 VPN.