led during manufacturing on the router/ switch boards. The thinking is that tightly integrating the optics with the electronics removes the cost of the packaging associated with pluggability and the need for separate testing. An industry effort called Consortium for Onboard Optics (COBO) [10] has been launched and has strong repre- sentation by the optics and switch/router community. 13.2 MPLS PACKET LAYER The purpose of the core packet layer is to provide global interconnectivity for the edge services platforms described in Chapter 12. This section covers the edge/core design paradigm, the evolution of the MPLS implementation, the transformation for core routing technologies, and the evolution of RR design. 13.2.1 IP COMMON BACKBONE An important design decision early in the development of the all-IP network is the adoption of an edge/core paradigm. There are two key drivers: 1. Efficiency-by aggregating the flow of traffic from many edges for transport across the core, the utilization of the costly long haul optical resources is improved. 2. Separation of functions-the edge is focused on the agile delivery of new and innovative solutions meeting enterprise and consumer needs. Edge platforms need to cost-effectively anchor many customer access connections, both high- and low-speed, and historically TDM, synchronous optical networking (SONET), and Ethernet. The core is all about scal- able and reliable bulk transport. The edge and core will each evolve at their own pace. A new services offering should never create any requirements to evolve the core. AT&T uses the term IP Common Backbone (CBB) to describe the core. Today's IP CBB carries over 100 petabytes of data a day. It is a seamless global network providing services in hundreds of countries. There are common design paradigms used globally-giving AT&T scale, efficiency, and reliability. The CBB supports all of AT&T's enterprise and consumer services including Consumer broadband Internet access IPv4/IPv6 internet connectivity IPv4/IPv6 VPN service Ethernet serv