Bandwidth Impacts of Localizing Peer-to-Peer IP Video Traffic in Access and Aggregation Networks

Abstract This paper examines the burgeoning impact of peer-to-peer (P2P) traffic IP video traffic. High-quality IPTV or Internet TV has high-bandwidth requirements, and P2P IP video could severely strain broadband networks. A model for the popularity of video titles is given, showing that some titles are very popular and will often be available locally; making localized P2P attractive for video titles. The bandwidth impacts of localizing P2P video to try and keep traffic within a broadband access network area or within a broadband access aggregation network area are examined. Results indicate that such highly localized P2P video can greatly lower core bandwidth usage.</p

Joint Optimization of Single-Carrier and Multi-Carrier DSL Spectra

Abstract – The loop plant can be optimized to provide significantly higher bit rates than currently provided, offering higher speeds that in some cases will even support digital entertainment video, without installing new remote terminals or repeaters. Algorithms for using measured crosstalk data to jointly optimize DSL performance have been recently published, and are based on finding the optimal transmit PSD in an iterative fashion. However, these algorithms can ensure joint optimization of homogenous DSL services only. In this paper, we present an iterative algorithm for jointly optimizing single-carrier and multicarrier DSL services. In particular, we address the case of joint optimization of ADSL and G.shdsl. Simulations are run with many different crosstalk couplings for several scenarios of loop length and numbers of crosstalkers. Simulation results show that average bit rate increases of several hundred percent are commonly achieved on relatively long loops with these Dynamic Spectrum Management (DSM) techniques. I

Signal processing for single-ended loop makeup identification

Broadband digital subscriber line (DSL) access for small business and residential customers is one of the most important new services currently being offered by network and service providers. To date, DSL service providers are still in need of an advanced loop qualification system that can minimize qualification errors. Loop qualification consists of determining whether a loop can support DSL services or not and, generally, the estimate of the loop transfer function is sufficient for such purposes. We propose here to solve a more ambitious problem: single ended automatic loop make-up identification (LMID), i.e. the determination of the length and the gauge of all loop sections (including bridged taps) via single-ended testing without human intervention. It is proposed here to use Time Domain Reflectometry (TDR) measurements, which are analyzed by a novel step-by-step ML algorithm, to achieve accurate LMID. This problem is equivalent to resolving via a single sensor experiment an unknown number of closely spaced echoes, some overlapping some not, which exhibit unknown amplitudes, unknown times of arrival and unknown shapes. 1

Methods of Summing Crosstalk From Mixed Sources - Part I: Theoretical Analysis

Digital subscriber lines (DSLs) are fundamentally limited by crosstalk. The case where all crosstalk is from the same type of DSL has been studied over the years and accurate models have been standardized. However, crosstalk from multiple different types of DSLs is a relatively new area of study and models of summing mixed crosstalk have only recently been postulated. As more and more types of DSLs are deployed by multiple service providers, it is imperative to gain confidence in the method of modeling worst-case mixed crosstalk and to understand its limitations in order to enable efficient spectrum management of the loop plant. All known crosstalk summation methods are described here in detail and their properties are compared. This paper also presents a new methodology for deriving sound crosstalk summation methods. This new methodology consists of deriving lower bounds to the worst-case method, which is intrinsically too pessimistic. In particular, it has been ascertained that the Minkowski inequality and, to a lesser extent, the Hlder inequality, yield new crosstalk summation methods that exhibit appealing properties. It is also shown here that the standardized Full Service Access Network (FSAN) method is a particular case of the more general Minkowski-bound method. Finally, the accuracy of known and new summation methods is deeply analyzed and discussed in Part II of this work, where the problem of defining an accurate statistical modeling of the pair-to-pair crosstalk power coupling losses is also addressed