Cisco IOS and Cisco IOS XR provide a comprehensive implementation of MPLS TE. They use tunnel interfaces as an abstraction of TE LSPs. You can perform constraint-based routing using IS-IS or OSPF. RSVP performs the signaling of TE LSPs. You can configure different aspects of the protocol (for instance, graceful restart, reliable messages, authentication) that can influence the scalability and reliability of an MPLS TE implementation. You can use multiple traffic-selection mechanisms to inject traffic into a TE LSP. CBTS enables you to use the MPLS EXP value for this purpose.
DS-TE and FRR extend the basic functionality in Cisco MPLS TE. You can implement DSTE using the RDM or MAM models. Cisco FRR TE supports link, node, SRLG, bandwidth, and path protection.