MPLS TE uses MPLS’ circuit-switching properties to engineer TE tunnels with adequate
reserved resources along the tunnel path based on the trafﬁc carried by the tunnel. TE-
RSVP is used to establish the LSP-based TE path for a TE tunnel. TE extensions for OSPF
and IS-IS enable them to carry the available link resource information all over the network.
The famous quote on TE by Mike O’Dell of UUNET—“The efﬁcacy with which one
uses the available bandwidth in the transmission fabric directly drives the fundamental
‘manufacturing efﬁciency’ of the business and its cost structure”—eloquently captures the
reasoning for TE.