How does an MPLS Layer 3 VPN interconnect customer sites?

MPLS Layer 3 VPNs connect customer sites by leveraging the service provider's MPLS backbone. Customer Edge (CE) routers at each customer site peer with Provider Edge (PE) routers in the service provider network. The PE routers maintain separate routing tables (VRFs) for each VPN customer, ensuring traffic isolation. This CE-to-PE connectivity allows the service provider to transport customer traffic securely and efficiently across its network without the customer needing to manage complex tunneling or routing protocols across the public internet. The other options describe less secure, less scalable, or incorrect methods for MPLS L3 VPNs.