Multi-COBS: A Novel Algorithm for Byte Stuffing at High Throughput

Framing methods are used to break a data stream into packets in most digital communications. The use of a reserved symbol to denote the frame boundaries is a popular practice. This end-of-frame (EOF) marker should be removed from the packet content in a reversible manner. Many strategies, such as the bit and byte stuffing processes employed by high-level data link control (HDLC) and Point-to-Point Protocol (PPP), or the Consistent Overhead Byte Stuffing (COBS), have been devised to perform this goal. These bit and byte stuffing algorithms remove the reserved EOF marker from the packet payload and replace it with some extra information that can be used to undo the action later. The amount of data added is called overhead and is a figure-of-merit of such algorithms, together with the encoding and decoding speed. Multi-COBS, a new byte stuffing algorithm, is presented in this paper. Multi-COBS provides concurrent encoding and decoding, resulting in a performance improvement of factor four or eight in common word-based digital architectures while delivering an average and worst-case overhead equivalent to the state-of-the-art. On the reference 28-nanometer field programmable gate array (FPGA) (Artix-7), Multi-COBS achieves a throughput of 6.6 Gbps, instead of 1.7 Gbps of COBS. Thanks to its parallel elaboration capability, Multi-COBS is ideal for digital systems built in programmable logic as well as modern computers

Novel algorithms for fair bandwidth sharing on counter rotating rings

Rings are often preferred technology for networks as ring networks can virtually create fully connected mesh networks efficiently and they are also easy to manage. However, providing fair service to all the stations on the ring is not always easy to achieve. In order to capitalize on the advantages of ring networks, new buffer insertion techniques, such as Spatial Reuse Protocol (SRP), were introduced in early 2000s. As a result, a new standard known as IEEE 802.17 Resilient Packet Ring was defined in 2004 by the IEEE Resilient Packet Ring (RPR) Working Group. Since then two addenda have been introduced; namely, IEEE 802.17a and IEEE 802.17b in 2006 and 2010, respectively. During this standardization process, weighted fairness and queue management schemes were proposed to be used in the standard. As shown in this dissertation, these schemes can be applied to solve the fairness issues noted widely in the research community as radical changes are not practical to introduce within the context of a standard. In this dissertation, the weighted fairness aspects of IEEE 802.17 RPR (in the aggressive mode of operation) are studied; various properties are demonstrated and observed via network simulations, and additional improvements are suggested. These aspects have not been well studied until now, and can be used to alleviate some of the issues observed in the fairness algorithm under some scenarios. Also, this dissertation focuses on the RPR Medium Access Control (MAC) Client implementation of the IEEE 802.17 RPR MAC in the aggressive mode of operation and introduces a new active queue management scheme for ring networks that achieves higher overall utilization of the ring bandwidth with simpler and less expensive implementation than the generic implementation provided in the standard. The two schemes introduced in this dissertation provide performance comparable to the per destination queuing implementation, which yields the best achievable performance at the expense of the cost of implementation. In addition, till now the requirements for sizing secondary transit queue of IEEE 802.17 RPR stations (in the aggressive mode of operation) have not been properly investigated. The analysis and suggested improvements presented in this dissertation are then supported by performance evaluation results and theoretical calculations. Last, but not least, the impact of using different capacity links on the same ring has not been investigated before from the ring utilization and fairness points of view. This dissertation also investigates utilizing different capacity links in RPR and proposes a mechanism to support the same

Automatic database acquisition software for ISDN PC cards and analogue boards

This paper describes an application for automatic speechdatabases acquisition (ADA) developed by the authors in the framework of the EC Telematics Project SpeechDat II. The software is able to work with standard inexpensive PC cards for ISDN lines, as well as Dialogic Boards for analogue telephone lines. Both program versions share a common file format and configuration. Other important characteristics of the recording software are its simple set-up, a fast and flexible configuration of the recording session, the real-time monitoring of calls and disk space, and its proven robustness.Peer ReviewedPostprint (published version

Configurable byte-wide HDLC controller supporting IP over SONET

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1998.Includes bibliographical references (p. 66-67).by Daniel T. Lee.M.Eng

Descripción de la tecnología de jerarquía digital sincrona de nueva generación (SDH-NG)

La nueva generación SONET/SDH (NG-SDH) es un término que aunque a simple vista aparente algo único, en realidad abarca un amplio un rango de desarrollos basados en estándares y propietarios que están construidos sobre la infraestructura SONET/SDH disponible actualmente. Desplegado primeramente por operadores de larga distancia como una forma para soportar nuevos servicios tales como Ethernet, Fibre Channel, ESCON, y DVB, la nueva generación SONET/SDH permite la entrega de datos con alta velocidad, y muy alto ancho de banda aún con presupuestos muy limitados. La nueva generación de SONET/SDH extiende la utilidad de la red existente de SONET/SDH utilizando la red de capa uno e incluyendo tecnologías tales como la concatenación virtual (VC), el procedimiento genérico de trama (GFP), y el esquema de ajuste de la capacidad de enlaces (LCAS). En general, la concatenación virtual mapea contenedores individuales en un enlace virtualmente concatenado. Así, Cualquier número de contenedores puede ser agrupado lo que provee mejor granularidad en el ancho de banda que el obtenido usando técnicas tradicionales (concatenación contigua por ejemplo). Adicionalmente, esto permite a los operadores de redes ajustar la capacidad de transporte requerido para el servicio del cliente para su mejor eficiencia. Debido a que los nodos intermedios de la red tratan cada contenedor en el enlace como uno estándar, solo el equipo de inicio de trayectoria y el del fin de trayecto necesitan reconocer y procesar la estructura de la señal virtual concatenadaIncluye bibliografí

Design and construction of a low earth orbit satellite ground station

Thesis (M.S.) University of Alaska Fairbanks, 2000This thesis describes the design and construction of a satellite ground station constructed in support of the Citizen Explorer Program. The University of Alaska Fairbanks was chosen to participate in this program due to its latitude that gives it excellent access to polar-orbiting satellites. The advantage that higher latitudes have in accessing low earth orbiting satellites is examined. It is demonstrated that Fairbanks, Alaska, has roughly twice the access to polar orbiting satellites than the mid-latitudes of the contiguous US. Link budgets for the communication system were developed, which led to the construction of helical antennas to communicate with the satellite. Data are presented that demonstrate the antennas, as well as the rest of the satellite tracking system, functioned acceptably. The satellite ground station will provide internet access to the spacecraft. The procedure used to test this approach and its results are given, as well as recommendations for future work

Interligação de sistemas IP em redes SDH

Mestrado em Engenharia Electrónica e TelecomunicaçõesNo presente trabalho propõe-se estudar as metodologias existentes de integração e implementação do protocolo IP sobre as diferentes tecnologias RPR, ATM, MPLS, Ethernet e HDLC suportadas na rede de transporte de dados SDH. São apresentadas interfaces capazes de suportar um MAC da actual norma do RPR (IEEE 802.17) sobre um meio puramente Ethernet (IEEE 802.3) ou sobre o meio de transporte de dados SDH. Também serão apresentadas interfaces capazes de introduzir tráfego ATM sobre a rede SDH. A primeira parte deste documento, correspondente ao primeiro e segundo capítulo, aborda as necessidades e identifica as interfaces suportadas por um sistema de transporte de dados desta natureza. São também apresentadas algumas soluções comercias existentes no mercado, desenvolvidos por alguns fabricantes e operadores assim como alguns exemplos de ambientes de utilização para este tipo de produtos. A segunda parte corresponde ao terceiro capítulo, e é composta por uma abordagem ao trabalho desenvolvido pelo consorcio SIRAC que envolveu empresas e algumas entidades académicas e de investigação da área das telecomunicações na necessidade de estudo e de desenvolvimento de novas soluções tecnológicas. Foram feitas duas abordagens distintas em que primeiro se estudou uma tecnologia recente, que pretende afirmar-se no mercado (RPR), e por fim outra mais madura (ATM) que permitiu equacionar diferentes cenários de evolução da rede. O quarto capítulo pertence à terceira parte deste documento, onde é descrito todo o desenvolvimento e testes elaborados às interfaces desenvolvidas no decorrer desta dissertação. É também apresentado um estudo referente à tecnologia de micro electrónica FPGA utilizada neste trabalho assim como alguns dados resultantes da síntese e “place and route” efectuados sobre o código HDL desenvolvido. Por fim no quinto capítulo apresentam-se as respectivas conclusões. São ainda apresentados alguns anexos onde se expõe alguns diagramas de algumas entidades lógicas da tecnologia FPGA, bem como código HDL de programação em FPGA para implementação de alguns circuitos de CRC (cyclic redundancy check) paralelos. ABSTRACT: The present work is intended to study the existing methodologies for integration and implementation of the Internet Protocol IP with the RPR, ATM, MPLS, Ethernet and HDLC technologies, based on a SDH environment. Some interfaces are presented to support a RPR (IEEE802.17) MAC on Ethernet or SDH technologies and also interfaces capable of introducing ATM traffic on SDH networks. The first part of this document, corresponding to the first and second chapter, currently approaches the necessity of the interfaces used for a system of this nature, followed of a brief presentation of solutions and existing products in the market, developed by some manufacturers and operators. The second part, corresponding to the third chapter, presents an approach of the work developed in the SIRAC consortium that involved some companies and academic and research institutions in order to study and develop new technology solutions including the RPR and ATM standard technologies. The fourth chapter belong to the third part of this document, where it is described all the development and test made to the interfaces involved in this work. It also presents a FPGA technology study used in this work including synthesis and place and route analyses. Finally in the fifth chapter the respective conclusions are presented. Still some annexes are presented describing some FPGA unit logic diagrams and some HDL code for FPGA programming implementing a CRC (cyclic redundancy check) parallel algorithm

Implementação de IP sobre novas camadas físicas

Mestrado em Engenharia Electrónica e TelecomunicaçõesO presente trabalho propõe-se estudar as metodologias existentes de integração e implementação do protocolo Internet sobre sistemas de telecomunicações. É apresentada a descrição da actual norma do RPR (IEEE 802.17) e em paralelo as opções de desenvolvimento para a implementação dos módulos do MAC (Medium Access Control), para o transporte de IP sobre uma rede em anel, segundo esta norma. A primeira parte deste documento correspondente ao primeiro capítulo, aborda os serviços existentes actualmente para transporte de dados em pacotes, nas actuais redes de telecomunicações. A segunda parte correspondente aos segundo e terceiro capítulos, é composta por uma abordagem às principais metodologias utilizadas para mapeamento de IP sobre diversos protocolos para posterior transporte na camada física, seguida de uma apresentação breve de soluções e produtos existentes no mercado, desenvolvidos por alguns fabricantes e operadores. Os quarto, quinto e sexto capítulos, pertencem à terceira parte deste documento, onde é descrita a norma do IEEE 802.17 e as opções de desenvolvimento dos trajectos de dados do MAC, dos algoritmos de Fairness e de descoberta da Topologia e Protecção, e da unidade de Operação, Administração e Manutenção, para um sistema real desta referida norma. São descritas as soluções desenvolvidas para os diversos módulos e para todo o sistema que pressupõe a unidade de MAC do RPR. É também apresentada a implementação e simulação de um dos módulos do MAC do RPR. Por fim no sétimo capítulo apresentam-se as respectivas conclusões. São ainda apresentados dois anexos. O anexo A apresenta uma descrição detalhada de tipos e estruturas de tramas do protocolo Resilient Packet Ring - 802.17. No anexo B é descrita a estrutura da base de dados do algoritmo de descoberta de topologia e protecção, do referido protocolo.The present work is intended to study the existing methodologies of integration and implementation of the Internet Protocol in telecommunications systems. It also proposes a starting point for the implementation of a module for the MAC of an emerging protocol to transport IP over a ring net. The description of the current standard of the RPR (IEEE 802.17) is presented and in parallel, the options of development for the implementation of the MAC (Medium Access Control) modules, for the transport of IP on a ring network, according to this standard. The first part of this document, corresponding to the first chapter, currently approaches the existing services for transport of data in packages, in the present telecommunication networks. The second part, corresponding to the second and third chapters, is composed of an approach to the main methodologies used for IP mapping on diverse protocols for posterior transport in the physical layer, followed of a brief presentation of solutions and existing products in the market, developed by some manufacturers and operators. The fourth, fifth and sixth chapters, belong to the third part of this document, where it is described the 802.17 standard of the IEEE and the options for the development of the MAC datapaths, of the Fairness and Topology Discovery and Protection, algorithms, and of the Operation, Administration and Maintenance unit, for a real system of this standard. It is described the solutions developed for the several modules and for all the system that compose the unit of the RPR MAC. It is also presented the implementation and simulation of one of the modules of RPR MAC. Finally in the seventh chapter the respective conclusions are presented. Still two annexes are presented. The annex A presents a detailed description of frame types and structures of the Resilient Packet Ring – 802.17 protocol. In the annex B it is described the structure of the database for the topology discovery and protection algorithm, of the related protocol