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Afifi, Mohammed Ahmed Melegy MohammedTCP FTAT (Fast Transmit Adaptive Transmission): A New End-To- End Congestion Control Algorithm
Master of Science in Electrical Engineering, Cleveland State University, 2014, Washkewicz College of Engineering
Congestion Control in TCP is the algorithm that controls allocation of network resources for a number of competing users sharing a network. The nature of computer networks, which can be described from the TCP protocol perspective as unknown resources for unknown traffic of users, means that the functionality of the congestion control algorithm in TCP requires explicit feedback from the network on which it operates. Unfortunately this is not the way it works with TCP, as one of the fundamental principles of the TCP protocol is to be end-to-end, in order to be able to operate on any network, which can consist of hundreds of routers and hundreds of links with varying bandwidth and capacities. This fact requires the Congestion Control algorithm to be adaptive by nature, to adapt to the network environment under any given circumstances and to obtain the required feedback implicitly through observation and measurements. In this thesis we propose a new TCP end-to-end congestion control algorithm that provides performance improvements over existing TCP congestion control algorithms in computer networks in general, and an even greater improvement in wireless and/or high bandwidth- delay product networks.

Committee:

Nigamanth Sridhar, PhD (Committee Chair); Chansu Yu, PhD (Committee Member); Pong Chu, PhD (Committee Member)

Subjects:

Computer Engineering; Computer Science; Electrical Engineering

Keywords:

TCP; Congestion Control; Computer Networks; TCP NewReno; TCP Westwood; TCP Cubic; Linux TCP; ns-3; DCE Cradle; Direct Code Execution Cradle - ns-3; high bandwidth delay product networks; random loss radio signal; Adaptive Transmission

Barritt, Brian JamesThe Modeling, Simulation, and Operational Control of Aerospace Communication Networks
Doctor of Philosophy, Case Western Reserve University, 2017, EECS - Computer Engineering
A paradigm shift is taking place in aerospace communications. Traditionally, aerospace systems have relied upon circuit switched communications; geostationary communications satellites act as bent-pipe transponders and are not burdened with packet processing and the complexity of mobility in the network topology. But factors such as growing mission complexity and NewSpace development practices are driving the rapid adoption of packet-based network protocols in aerospace networks. Meanwhile, several new aerospace networks are being designed to provide either low latency, high-resolution imaging or low-latency Internet access while operating in non-geostationary orbits -- or even lower, in the upper atmosphere. The need for high data-rate communications in these networks is simultaneously driving greater reliance on beamforming, directionality, and narrow beamwidths in RF communications and free-space optical communications. This dissertation explores the challenges and offers novel solutions in the modeling, simulation, and operational control of these new aerospace networks. In the concept, design, and development phases of such networks, the dissertation motivates the use of network simulators to model network protocols and network application traffic instead of relying solely on link budget calculations. It also contributes a new approach to network simulation that can integrate with spatial temporal information systems for high-fidelity modeling of time-dynamic geometry, antenna gain patterns, and wireless signal propagation in the physical layer. And towards the operational control of such networks, the dissertation introduces Temporospatial Software Defined Networking (TS-SDN), a new approach that leverages predictability in the propagated motion of platforms and high-fidelity wireless link modeling to build a holistic, predictive view of the accessible network topology and provides SDN applications with the ability to optimize the network topology and routing through the direct expression of network behavior and requirements. This is complemented by enhancements to the southbound interface to support synchronized future enactment of state changes in order to tolerate varying delay and disruption in the control plane. A high-level overview of an implementation of Temporospatial SDN at Alphabet is included. The dissertation also describes and demonstrates the benefits of the application of TS-SDN in Low Earth Orbiting (LEO) satellite constellations and High Altitude Platform Systems (HAPS).

Committee:

Frank Merat (Committee Chair); Rabinovich Michael (Committee Member); Daniel Saab (Committee Member); Mark Allman (Committee Member)

Subjects:

Aerospace Engineering; Computer Engineering; Computer Science

Keywords:

temporospatial; SDN; TS-SDN; aerospace; networks; satellites; LEO; NGSO; constellations; HAPS; high-altitude platforms; STK; wireless; mesh; networking; modeling; simulation; ns-3