MPLS-signaled LSPs to use GRE tunnels

MPLS label-switched paths (LSPs) can use generic routing encapsulation (GRE) tunnels to traverse routing areas, autonomous systems, and ISPs.Bridging MPLS LSPs over an intervening IP domain is possible without disrupting the outlying MPLS domain. This feature is supported on the Channelized OC3/STM1 (Multi-Rate) Circuit Emulation MIC with SFP and is defined in the RFC 4023, Encapsulating MPLS in IP or Generic Routing Encapsulation (GRE).