78 CHAPTER 3 Converged Networks are used for telecommunication applications and, conversely, data communication networks that are used for telecommunications applications. Network technologies that are most likely to use high-end Network Processors applications in network nodes (devices) are Ethernet (enterprise and carrier class), MPLS, and IP. Therefore, most of the description in this chapter is focused on these networks, with some discussion of other network technologies required for an overview of how networks are combined, relate to each other, and evolve. 3.2 FROM TELECOM NETWORKS TO DATA NETWORKS As noted before, one convergence approach between data networks and telecommunications networks is to adopt various techniques that enable transmis- sion of data-patterned traffic over telecommunications networks. The idea of such convergence has also led a move toward more data-centric traffic in traditional telecommunications networks, equipment, and services. As of today, SONET/SDH is the technology that has the greatest chance of dominating data and telecommunications networks, mainly due to the huge installed