What does MPLS VPN utilize to forward traffic among core routers?

MPLS (Multiprotocol Label Switching) VPN operates by making use of labels to efficiently forward traffic among core routers. In an MPLS network, data packets are assigned short, fixed-length labels that are used to make routing decisions. These labels expedite the packet forwarding process because routers don't need to look up the destination IP address in a routing table; they can simply forward packets based on the attached label.

When a packet enters the MPLS network, the label is assigned at the ingress router, and as it traverses through the core routers, each router only inspects the label to determine the appropriate output path. This label switching is fundamental to MPLS, as it enables quick and efficient routing even in complex networks, optimizing bandwidth usage and improving overall performance.

While other factors such as IP addressing play a role in network identity and routing, they are not the primary means of traffic forwarding within an MPLS VPN. Similarly, encryption is a security measure that can be employed but does not influence how traffic is directed through the MPLS infrastructure. Headers, while important for encapsulating information about the packets, do not provide the same level of efficiency in forwarding decisions that labels do in MPLS. Therefore, labels are the correct answer as they are the