Peter J. Silverman

Software-defined access networks

Control-plane functions are migrating from dedicated network equipment into software running on commodity hardware. The Software- Defined Access Network (SDAN) concept introduced here extends the benefits of Software- Defined Networking and Network Function Virtualization (NFV) into broadband access. In a SDAN, access-network control and management functions for broadband access are virtualized, to streamline operations, speed services creation, and enhance broadband customer satisfaction, particularly in multi-operator environments. This article examines industry drivers, identifies software- definable control and management functions for broadband access, and presents some specific usage scenarios for the SDAN.

Digital subscriber lines

Digital Subscriber Lines (DSLs), transmission systems that allow high-speed digital transmission on ordinary phone lines, are overviewed in this article. This article focuses mainly on the transmission technologies and the challenges of high-speed transmission on twisted-pair phone lines, but also considers basic terms of reference and network/applications interfaces. Loop topology, transmission impairments, and transmission techniques are reviewed for the most popular DSLs, as are the basic connections necessary for a complete ADSL service through a service-providers network. For a more complete discussion of DSLs, see the book by the same three authors [J. Cioffi, T. Starr, P. Silverman, Digital Subscriber Lines, Prentice-Hall, Upper Saddle River, NJ, 1998].

Greener Copper with Dynamic Spectrum Management

Power-saving benefits of Dynamic Spectrum Management (DSM) result from its increased robustness to channel and noise changes, as in this paper. A proposed intermittent noise model enables evaluation of the performance of DSM algorithms. Polite Level-1 DSM algorithm consumes much less power than non-polite DSL management algorithms in the presence of intermittent noise. Secondly, a proposed robust level- 2 DSM algorithm compares favorably with methods that change the PSDMASK only upon modem initialization or retraining. The proposed robust level-2 DSM algorithm significantly reduces power consumption. This DSM reduction of DSL transmit power can be even more significant when considering the additional loss of robustness and stability of non-DSM methods.

Fixed Access Network Sharing

Deep fiber deployments for ultrafast broadband are both technically and economically challenging. Fixed access network sharing (FANS) offers a highly enhanced form of virtual unbundling of broadband access networks, enabling cost sharing and the dynamics of a competitive landscape. Data, control, and management interfaces are automated and harmonized among wholesale infrastructure providers and retail virtual network operators. Standardized FANS interfaces can greatly decrease OPEX while increasing customer satisfaction. When FANS is implemented, network slicing logically partitions and isolates network resources among the VNOs, and such sharing can split the cost of network upgrades among several entities. FANS works with virtualization, where control plane functions are migrated from dedicated network equipment into software running on commodity hardware, with FANS providing network as a service. This article describes the drivers behind FANS, several architectures supporting FANS, and emerging standards supporting FANS.