Abstract
Metropolitan Area Networks (MANs) are defined as networks spanning distances up to several hundred kilometers, typically serving large, concentrated metropolitan areas. Current metroarea network topologies are largely ring-based. SONET/SDH is the technology used in the metro area, using point-to-point or add-drop multiplexer (ADM) ring topologies. Connections are either permanent or semi-permanent with access rates ranging from OC-3 to OC-48.

Metro networks present many engineering challenges, especially as there is a large base of legacy SONET/SDH (Synchronous Optical Network/Synchronous Digital Hierarchy) infrastructure prevalent in current metro-area networks. These traditional TDM (time-division multiplexing) networks were originally designed to transport a limited set of traffic types, mainly multiplexed voice and private line services (such as DS-1 and DS-3). Today’s metro market is under pressure to handle the rapidly growing capacity demands and increasingly varying traffic patterns. The increase in long-haul DWDM capacity coupled with the rise of (access) IP bandwidth demand has placed a focus on the metro network to provide additional capacity.

This white paper tries to envision a metro network where technologies such as Multi Protocol Label Switching (MPLS), Resilient Packet Ring, (RPR) and Automatically Switched Optical Network (ASON) would work together and remove bottlenecks and streamline network efficiency. The paper begins with a brief description of a typical current metro network, the technologies used and typical metro provider requirements. A brief description of the newer technologies that are being considered follows along with their individual advantages; a unified network where all these technologies co-exist & work in unison and the inherent advantages and disadvantages of such a network.

Authors Gayathri Manoj Kandasamy Varadharaj Shri Krishan RamNarayan S

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