Which of the following are functions of the MPLS control plane in a router? (Choose two)

The MPLS control plane is responsible for establishing and maintaining Label Switched Paths (LSPs). This involves two primary functions. First, routers must allocate labels for the Forwarding Equivalence Classes (FECs) they can reach and manage these label bindings (A). Second, they must signal or advertise these label bindings to other routers using a signaling protocol like LDP or RSVP-TE (D). These actions create the forwarding information that the data plane will use.

B. Label swapping is a data plane (forwarding plane) operation performed on a labeled packet as it transits a Label Switching Router (LSR).
C. Pushing a label onto an unlabeled packet is a data plane operation performed by the ingress Label Edge Router (LER).
E. While routing protocols run in the control plane, "routing lookups" typically refer to the data plane action of forwarding a packet based on its destination.

1. Nokia, SR OS MPLS Guide, Release 21.10.R1, Document ID: 3HE 17179 AAAA TQZZA, 2021, Section: "MPLS Architecture", pp. 33-34. (Describes control plane functions including label distribution via signaling protocols and data plane functions like push/swap/pop).

2. Rosen, E., Viswanathan, A., & Callon, R., Multiprotocol Label Switching Architecture, RFC 3031, IETF, January 2001, Section 2.1 "The Forwarding Component" and Section 2.2 "The Control Component". (Defines the control component's responsibility for creating and maintaining label bindings).