With its ubiquity, simplicity, speed, and economics, Ethernet has become the technology of choice for packet transport networks.
However, native Ethernet, with its roots in the enterprise, lacks the scale, reliability, and performance that are essential for its successful transition from the LAN to the MAN/WAN. Carriers today are faced with using two alternative ways of making Ethernet carrier grade: MPLS and PBB-TE (PBT).
This paper goes beyond the marketing hype and look closely at the underlying concepts behind MPLS and PBT.