Design of metro Ethernet networks

Metropolitan (metro) carriers are deploying next-generation metro Ethernet networks. This deployment will eventually replace traditional private-line services provided by legacy Time Division Multiplexing (TDM) technologies (such as Digital Cross-Connect Systems and SONET rings) with metro Ethernet services. A critical near-term need is the enabling of rich wireless data applications and, thus, begins a massive upgrade of backhaul links from cellular base stations to their Mobile Telephone Switching Offices (MTSOs), where the various voice and data applications will be provided. These base stations are evolving to 3G/4G technology and require metro Ethernet transport and at significantly higher backhaul technology than the prevalent TDM DS1s (1.5 Mb/s). In this paper, we describe a methodology to enable the rapid introduction of metro Ethernet networks, which includes architecture planning, switch location selection, link placement and sizing, as well as customization for cellular network reliability. Our approach uses a combination of many optimization algorithms and has been integrated into a pragmatic tool used by AT&T network planners. Case studies in very large US metro areas have shown that the tool gives cost-ffective solutions consistent with planner expectations and intuition.