Hi Jimmy,

To do MPLS TE, basically every LSR must have the entire network topology which can be done only via using OSPF or ISIS (as they are the only IGPs that hold the entire topology) --> Accordingly OSPF or ISIS with MPLS TE extensions is needed.

OSPF and ISIS MPLS TE extensions can propagate available resources and constraints of all network links.

Either RSVP or CR-LDP can be used to create the TE tunnel and propagate the TE Labels in the control plane.

NOTE: Because RSVP with TE extensions takes care of the distribution of the MPLS labels, you do not need to configure Label Distribution Protocol (LDP) on the interfaces. Therefore, the MPLS network does not strictly need to have mpls ip on the interfaces, if TE is deployed. However, if you do not deploy TE to carry all traffic from ingress LSRs to egress LSRs, you need LDP to avoid unlabeled traffic in the core network. MPLS VPN traffic, for instance, needs to be labeled at all times in the core network.

HTH, please do rate if it does help,

Mohammed Mahmoud.