Which protocol does MPLS use to support traffic engineering?

Which protocol does MPLS use to support traffic engineering?
A . Tag Distribution Protocol
B . Label Distribution Protocol
C . Border Gateway Protocol
D . Resource Reservation Protocol

Answer: D

Explanation

The Resource Reservation Protocol (RSVP) is a network control protocol used by a host to request specific qualities of service from the network for particular application data streams or flows. RSVP is also used by routers to deliver quality of service (QoS) requests to all nodes along the path(s) of the flows and to establish and maintain operational state to provide the requested service. In general, RSVP requests result in resources reserved in each node along the data path.

The Resource Reservation Protocol for Traffic Engineering (RSVP-TE) is an extended version of RSVP for MPLS. RSVP-TE uses traffic engineering extensions to support automatic signaling of LSPs. MPLS uses RSVP-TE to set up traffic-engineered LSPs.