The vision of network convergence toward a consolidated packet-based network has been discussed for years, though it is still not a reality. Currently, there are numerous overlay networks such as IP, ATM, Frame Relay (FR), Ethernet, SONET, DWDM and wireless for different services. The evolution pace toward convergence has been slow due to economic, technical and regulatory issues. However, the fact is that data traffic volume is now surpassing voice traffic volume. Traditional Time Division Multiplexing (TDM) voice traffic is moving to IP packets and TDM private line is moving to Ethernet private line. The wave of broadband applications such as Internet access, Video on Demand (VoD), and IPTV create high bandwidth requirements for the network. These applications are packet-based, but have a much lower margin of profit for the service providers when compared to traditional voice service. Today's overlay and traditional circuit-based infrastructure will become less optimal for the new packet-based services as the profit margin decreases. Most of the wireless networks in North America today are still circuit-based because most of the current wireless service is still voice-based. However, with emerging wireless access technologies such as Worldwide Interoperability for Microwave Access (WiMAX) and Wireless Fidelity (Wi-Fi), more broadband wireless data and video services can be deployed. As a result, the wireless core network evolves toward a packet-based network. Service offerings drive network evolution. As more packet-based broadband services are launched and bundled together in service offerings, service providers start to add more packet-aware features into their current network components. Eventually, network convergence toward a single packet-based network infrastructure is likely to become a reality for wireline and wireless networks. Pseudowire (PW) is a promising MPLS-based packet transport technology that decouples the service layer from the underlying infrastructure, so service providers can leverage their existing transport technologies. Whether the underlying infrastructure is SONET, DWDM or Ethernet, PW provides a common encapsulation layer that can support the transport of TDM, ATM, Frame Relay, IP/PPP, and Ethernet services. PW can protect the service providers' current investment and provide a smooth migration path from circuit-based to packet-based networks. In this paper, new emerging broadband technologies will be discussed. This paper illustrates how those technologies can be integrated together to provide a seamless converged wireline and wireless network and outlines the challenges ahead to make the vision of a packet-based network successful.
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