Many core networks are built over IP/MPLS both nationally and internationally.
IP/MPLS or L3VPN is a technology where the traffic is carried over pseudowires (PW) over MPLS Label Switch Paths (LSPs) tunnels. The forwarding is L3-based. The infrastructure comprises routers that are MPLS-capable. Such a network can provide connectivity service to subscribers, in a similar manner to the way CEN provides Ethernet services.
These L3 services are non-standard, and there is currently no standards development organization that is attempting to create standards for such services. In contrast to L3VPN, Ethernet services are built on the concept of Ethernet based forwarding, hence can be referred to as L2VPN. When we consider L3VPN Vs. L2VPN the following comparison can be made.
In some cases a global solution may result in a combination of L2VPN and L3VPN services. The main reason is that for long haul, forwarding based on Ethernet addresses sometimes does not scale sufficiently, whereas L3VPNs are available throughout the globe on international links.