NeTS: Medium: Collaborative Research:Digital SubCarrier Multiplexing (DSCM) Networks: from the Core to the Access

在海量视频流、云计算和物联网的推动下，互联网流量正在经历快速增长。对于控制能源消耗，同时保证良好的服务质量，绿色网络比以往任何时候都更加重要。分组交换是高速互联网中的标准实践，通过在每个中间节点执行电子分组存储和转发的路由器和交换机来实现。在典型的路由器中，高达60%的能量用于数据包转发。另一方面，电路交换不需要按数据包存储和转发，并且可能会更节能。目前的做法是将光学电路放置在固定的光学频率栅格上。如果光路承载的容量小于最大容量，这种固定网格可能会浪费宝贵的光谱。因此，研究界和产业界都在研究无网格方法。特别是，数字副载波复用(DSCM)是一种面向电路的方法，具有高频谱效率和对信号质量恶化的稳健性，并能够在光网络中实现灵活的频谱和无网格传输。该项目利用DSCM将面向电路的实践从光网络核心一直延伸到网络外围(包括城域、接入和园区段)，最终向最终用户提供专用的宽带DSCM电路。DSCM流量绕过了以太网交换机和互联网协议路由器，并消除了与其数据包存储和转发要求相关的能源消耗。该项目还探索了一种混合-DSCM-以太网网络体系结构，其中DSCM电路和以太网帧在接入/园区网络中共存。这项研究的传输和网络跨层性质促进了不同机构和研究领域之间的合作，并为研究生和本科生提供了研究解决现实世界科学问题的机会。

Internet traffic is experiencing a rapid growth driven by massive video streaming, cloud computing and the Internet of Things. Green networking is more important than ever to keep energy consumption under control while still guaranteeing good service quality. Packet switching is the standard practice in high speed Internet, enabled by routers and switches that perform electronic packet store-and-forward at every intermediate node. In a typical router, up to 60 percent of its energy is used for packet forwarding. Circuit switching, on the other hand, does not require per-packet store-and-forward and can potentially be more energy efficient. Current practice places optical circuits on a fixed grid of optical frequences. This fixed grid may waste valuable optical spectrum if an optical circuit is carrying less than the maximum capacity. Thus both the research community and industry are investigating grid-less approaches. In particular, Digital Subcarrier Multiplexing (DSCM)is a circuit-oriented approach with high spectral efficiency and robustness against signal quality corruption and which enables flexible spectrum and grid-less transmission in optical networks. This project leverages DSCM to extend the circuit-oriented practice from the optical network core all the way to the network periphery (including metro, access and campus segments) ultimately offering dedicated broadband DSCM circuits to end-users. DSCM traffic bypasses both Ethernet switches and Internet Protocol routers, and eliminates the energy consumption associated with their packet store-and-forward requirements. The project also explores a Hybrid-DSCM-Ethernet network architecture in which DSCM circuits and Ethernet frames coexist in the access/campus networks. The transmission and network cross-layer nature of this research effort promotes partnerships among different institutions and research areas, and provides graduate and undergraduate students the opportunity to do research solving real-world scientific problems.