A Network Congestion control Protocol (NCP)

The transmission control protocol (TCP) which is the dominant congestion control protocol at the transport layer is proved to have many performance problems with the growth of the Internet. TCP for instance results in throughput degradation for high bandwidth delay product networks and is unfair for flows with high round trip delays. There have been many patches and modifications to TCP all of which inherit the problems of TCP in spite of some performance improve- ments. On the other hand there are clean-slate design approaches of the Internet. The eXplicit Congestion control Protocol (XCP) and the Rate Control Protocol (RCP) are the prominent clean slate congestion control protocols. Nonetheless, the XCP protocol is also proved to have its own performance problems some of which are its unfairness to long flows (flows with high round trip delay), and many per-packet computations at the router. As shown in this paper RCP also makes gross approximation to its important component that it may only give the performance reports shown in the literature for specific choices of its parameter values and traffic patterns. In this paper we present a new congestion control protocol called Network congestion Control Protocol (NCP). We show that NCP can outperform both TCP, XCP and RCP in terms of among other things fairness and file download times.unpublishe

Network emulation focusing on QoS-Oriented satellite communication

This chapter proposes network emulation basics and a complete case study of QoS-oriented Satellite Communication

Estimating packet loss rate in the access through application-level measurements

End user monitoring of quality of experience is one of the necessary steps to achieve an effective and winning control over network neutrality. The involvement of the end user, however, requires the development of light and user-friendly tools that can be easily run at the application level with limited effort and network resources usage. In this paper, we propose a simple model to estimate packet loss rate perceived by a connection, by round trip time and TCP goodput samples collected at the application level. The model is derived from the well-known Mathis equation, which predicts the bandwidth of a steady-state TCP connection under random losses and delayed ACKs and it is evaluated in a testbed environment under a wide range of different conditions. Experiments are also run on real access networks. We plan to use the model to analyze the results collected by the "network neutrality bot" (Neubot), a research tool that performs application-level network-performance measurements. However, the methodology is easily portable and can be interesting for basically any user application that performs large downloads or uploads and requires to estimate access network quality and its variation

Mesmerizer: A Effective Tool for a Complete Peer-to-Peer Software Development Life-cycle

In this paper we present what are, in our experience, the best practices in Peer-To-Peer(P2P) application development and how we combined them in a middleware platform called Mesmerizer. We explain how simulation is an integral part of the development process and not just an assessment tool. We then present our component-based event-driven framework for P2P application development, which can be used to execute multiple instances of the same application in a strictly controlled manner over an emulated network layer for simulation/testing, or a single application in a concurrent environment for deployment purpose. We highlight modeling aspects that are of critical importance for designing and testing P2P applications, e.g. the emulation of Network Address Translation and bandwidth dynamics. We show how our simulator scales when emulating low-level bandwidth characteristics of thousands of concurrent peers while preserving a good degree of accuracy compared to a packet-level simulator

Supporting Cyber-Physical Systems with Wireless Sensor Networks: An Outlook of Software and Services

Sensing, communication, computation and control technologies are the essential building blocks of a cyber-physical system (CPS). Wireless sensor networks (WSNs) are a way to support CPS as they provide fine-grained spatial-temporal sensing, communication and computation at a low premium of cost and power. In this article, we explore the fundamental concepts guiding the design and implementation of WSNs. We report the latest developments in WSN software and services for meeting existing requirements and newer demands; particularly in the areas of: operating system, simulator and emulator, programming abstraction, virtualization, IP-based communication and security, time and location, and network monitoring and management. We also reflect on the ongoing efforts in providing dependable assurances for WSN-driven CPS. Finally, we report on its applicability with a case-study on smart buildings

Synchronization of hierarchical data

Synchronizace a přenos komplexních dat po síti může být náročným problémem. Společnost Pocket Virtuality potřebovala řešení pro svou platformu pro vzdálenou přítomnost, která by poskytovala synchronizační služby mezi zařízeními v této platformě. Tato zařízení musí mít možnost rychle a snadno vyměňovat velká a komplexní hierarchická data ve formě grafů scén obsahujících 3D modely, textury a další binární data a synchronizovat kopie těchto struktur na jiných zařízeních. Tato práce se zabývá analýzou stávajícího prostředí platformy Fata Morgana a jejích požadavků. Tato analýza je pak základem pro seznam funkčních a nefunkčních požadavků na síťové řešení. Knihovna FMLink je výsledkem fáze návrhu a implementace této práce. Jedná se o síťovou knihovnu navrženou pro více platforem, vysoce efektivní a odolnou vůči zhoršeným síťovým podmínkám. Pro splnění bezpečnostních požadavků poskytuje FMLink podporu kryptografického protokolu TLS. Tato knihovna je testována proti mnoha možným degradacím sítě a testována v různých emulovaných síťových podmínkách. Testy prokázaly, že knihovna může být nasazena a použita mnoha aplikacemi v platormě Fata Morgana.Synchronization and transfer of complex data over the network can be a challenging problem. The company Pocket Virtuality needed a solution for its remote-presence platform, which would provide synchronization services between the devices in this platform. These devices need to quickly and easily exchange large and complex hierarchical data in the form of the scene graphs containing 3D models, textures, and other binary data and synchronize copies of these structures on other devices. \par This thesis revolves around the analysis of the existing environment of the Fata Morgana platform and its requirements. This analysis is then the basis for the list of functional and non-functional requirements of the networking solution. \par The FMLink library is the result of the design and implementation phase of this thesis. It is a networking library designed to be multi-platform, highly efficient, and resistant to degraded network conditions. To satisfy the security requirements, FMLink provides support for the TLS cryptographic protocol. \par This library is tested against multiple possible network degradations and tested in various emulated network conditions. The tests proved the library can be deployed and used by many Fata Morgana applications