Security
MPLS networks are usually considered to offer at least the same level of security as ATM or frame relay networks. It would probably be advisable for an enterprise user to encrypt any sensitive traffic prior to forwarding it over an MPLS core (this applies to any type of SP core, actually).
Broadly speaking, the security responsibilities of an NMS consist of protecting the network devices and the associated managed objects, which may include enforcing SNMPv3 usage across the network. The security capability should also verify that the network and its traffic are secure from unauthorized access.