Which signaling protocol does MPLS use to support traffic engineering?

RSVP (Resource Reservation Protocol) is the signaling protocol MPLS uses for traffic engineering. It allows for the reservation of network resources, enabling the establishment of explicit paths (LSPs) with specific bandwidth and quality of service (QoS) requirements, which is fundamental to MPLS traffic engineering. TDP (Tag Distribution Protocol) is an older, proprietary Cisco protocol for distributing labels, largely superseded by LDP. LDP (Label Distribution Protocol) is the standard protocol for distributing labels in MPLS, but it does not inherently support traffic engineering capabilities like resource reservation. BGP (Border Gateway Protocol) is a routing protocol used for exchanging routing and reachability information between autonomous systems on the internet, not for MPLS label distribution or traffic engineering signaling.