1. Introduction

Many operators are interested in developing new business opportunities through the implementation of Network Centric Services (NCS), where the operator combines both network resources (raw connectivity) and IT resources (content storage and computing). Some examples of NCS include: PC virtualization, VoD, 3D Internet gaming, SaaS and SAN. These types of services and the expected continuous growth in Internet traffic (mainly driven by video) will severely impact the metro network. The costs of current metro architectures are tied to traffic growth; the higher the traffic the higher the network costs. Consequently, any cost increase will impact on the ISP's margins (ref. Figure 1). The network architectures of the last 20 years were never designed to cope with these new types of service demands. Therefore, new architectural solutions are needed to deliver the huge expected increase in traffic in a cost-effective way, and ensure low cost broadband Internet access in Europe. Figure 1: Economic threats of current metro network architectures