ABSTRACT
The network edge provides layer 2 and layer 3 service functions reached by the wired and wireless access networks. In the canonical reference model, the network edge platform (aka provider edge [PE]) sits between the many types of customer access networks (Chapter 11) and core networks (Chapter 13) and provides service processing, operations, administration and management (OA&M), and traffic aggregation functions (Figure 12.1). In this chapter, we describe the drivers, both business and technical, for the recent rapid evolution of packet edge platforms. In many existing networks, Ethernet is the base link packet technology for service PE networks because Ethernet VLANs are the fundamental unit for grooming and aggregation from the access technologies. Current merchant switches and routers provide very dense and inexpensive Ethernet interfaces to build a high-capacity IP Ethernet fabric to flexibly join access and core through the virtual network function (VNF) service applications. This chapter covers this transition in detail and explores where the boundary between software and hardware implementation can be drawn, so as to optimize the performance, yet maintain maximum flexibility.
