What is the primary role of a Provider (P) router in an MPLS network?

A Provider (P) router's primary role in an MPLS network is to act as a transit router within the service provider's core. P routers connect to Provider Edge (PE) routers, forwarding MPLS-labeled packets between them without needing to inspect the IP header or maintain customer VPN routing tables. They are responsible for label switching, which makes the core network highly efficient. Incorrect options: "To connect to customer edge (CE) devices" is the role of a PE router. "To impose MPLS labels" is primarily done by the ingress PE router. P routers perform label swapping. "To filter VPN routes in the core" is a function handled by PE routers, which manage VPN routing and forwarding (VRF) tables. P routers are unaware of customer VPN routes.