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Fueled by the ever growing consumption of digital content and services, providers of packet- switched networks suffer more and more a conflict between network engineering constraints and end-user usage patterns. This conflict is due to the fact that deployed networks exhibit low efficiency in their average resource utilization rate, which stands opposed to, at times, unsatisfiable resource request peaks generated by users. Multipath transmissions are theoretically able to temper this offset, but have been an uphill road due to the complexity they require to dominate. This article proposes a network paradigm able to transparently provide end users with such capabilities, by virtually pooling network resources through Software-Defined Networking. It is shown how this discipline may be deployed in current network infrastructures, while complying with the main 5G architectures envisaged so far. It is advocated how such an effort may allow service providers to meet users' expectations and strengthen profits without the need for unbearable financial investments, at the same time seamlessly improving their networks' performance, reliability, resource utilization efficiency and energy consumption. To demonstrate the technical feasibility and the potential benefits of the proposed approach, we present a set of emulation results showing that the sweet spot between n-fold performance increases and robust resilience properties can be practically met. [ABSTRACT FROM AUTHOR]

Ns-3 simulator provides a great platform for experimental studies on different communication technologies and network topologies, and it is already used by many researchers all around the world. Unfortunately, its current TCP implementation is outdated and not ready for being used as reference platform for TCP-centered research, relegating ns-3 to play a background role in favor of its predecessor, ns-2. This paper presents the update process of ns-3 TCP module, that offers to TCP developers and researchers a consistent and RFC-compliant platform to base their works on. The method involves the addition of a new congestion-based state machine, the split of congestion control out from the socket core, and the development of a very detailed and complete testing framework, which can be easily extended. Performance tests follow the description, comparing RAM usage and execution time between ns-3 releases. Also, a case study over high-delay links on the interaction between the Transmission Control Protocol (TCP) and CoDel, an Active Queue Management algorithm born to control queuing delay, is presented. [ABSTRACT FROM AUTHOR]

Wireless communications are critical for public protection and disaster relief (PPDR) professionals during the emergency operations that follow natural or man-made disasters, scenarios in which both commercial and dedicated terrestrial networks often fail to provide the necessary support. The reason is threefold: they simply get destroyed by the disaster, they cannot sustain the sudden surge of network demand or they fail to deliver the necessary bandwidth and/or other QoS guarantees. Because LTE is expected to become the main wireless technology for broadband communication, a lot of studies have been devoted to assess its compliance for PPDR purposes and to find suitable architectural solutions able to meet mission-critical requirements. This approach is surely worthy, but it is based on the assumption that infrastructure-based terrestrial systems are reliable. As a consequence, in worstcase emergency scenarios appropriate guarantees can be provided only in the hypothesis of huge investment costs. Recent developments in satellite technologies are bringing the availability of non-terrestrial high performance channels, with better properties when comparing to LTE for what regards availability and reliability. On this basis, the paper proposes a network architecture based on the integration of satellite and LTE networks for both infrastructure-based and infrastructure-less scenarios. The proposal aims to provide field operators and people in distress with transparent accessibility, coverage guarantees and broadband performance when terrestrial infrastructures are lacking, and to expand their coverage, capacity and resilience otherwise. [ABSTRACT FROM PUBLISHER]

Abstract: This paper introduces M_OBS_SIM, a network simulator conceived to evaluate the performance of networks where the Optical Burst Switching (OBS) paradigm is implemented. Its accurate design allows to investigate the behavior of optical edge and core routers, as well as to assess the performance of the whole optical network; its modular construction guarantees a high degree of flexibility and a facilitated introduction of further developments. Its functional blocks, properly configured, allow to explore the effects that the most salient features of an OBS network – input traffic statistics, assembly algorithms, resource reservation policies, routing strategies – have on user performance. New and valuable results for different classes of applications with diverse service requirements are provided and discussed. [Copyright &y& Elsevier]

This paper determines the performance of TCP when it is employed over a TDD-TD/CDMA architecture which supports different classes of subscribers and adopts an interference-driven admission control policy. The blocking and the outage probability of the system users are evaluated under various traffic conditions as well as the TCP throughput that data users experience. Call blocking and TCP throughput are determined by means of a semi-analytical approach. This work shows that when TCP is taken into account, many options come out for the system design in order to optimize radio resources. Resource assignment in the TDD-TD/CDMA system can then be done as a function of the actual radio link quality with the goal both to serve as many users as possible and to keep the TCP throughput as high as possible. Copyright © 2003 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Presents information on a proposal for Transmission Control Protocol-Internet Protocol (TCP-IP) backbone implementation based on optical packet switching technology. Possible solutions for interconnecting remote applications and subnetworks by means of optical technology; Background of optical transparent packet network (OTP-N); Solutions to support IT over OTP.

This paper presents and analyzes a test campaign's outcomes to assess the application-level performance of IEEE 802.11p at high speeds of up to 250 km/h. The main focus is on safety-related applications, but we also discuss performance figures resulting from additional tests performed to address other purposes that might use lower transmission powers. In particular, we investigate the impact that speed, transmission power, distance, and different degrees of congestion may have on application-level metrics such as TCP Goodput, UDP Goodput, RTT, Jitter, and Datagram/Packet Loss in real-world scenarios, and aim to find out which guarantees can be obtained in those environments with generic off-the-shelf equipment. Overall, the results indicate that IEEE 802.11p can satisfy safety-related requirements even as vehicles move with high velocity in heavily congested networks. For other kinds of applications, the performance might be compromised, especially under congestion, but figures attest that these networks may also serve additional purposes unanticipated when the standard was introduced. [ABSTRACT FROM AUTHOR]

Current data centers networks rely on electronic switching and point-to-point interconnects. When considering future data center requirements, these solutions will raise issues in terms of flexibility, scalability, performance, and energy consumption. For this reason several optical switched interconnects, which make use of optical switches and wavelength division multiplexing (WDM), have been recently proposed. However, the solutions proposed so far suffer from low flexibility and are not able to provide service differentiation. In this paper we introduce a novel data center network based on hybrid optical switching (HOS). HOS combines optical circuit, burst, and packet switching on the same network. In this way different data center applications can be mapped to the optical transportmechanism that best suits their traffic characteristics. Furthermore, the proposed HOS network achieves high transmission efficiency and reduced energy consumption by using two parallel optical switches. We consider the architectures of both a traditional data center network and the proposed HOS network and present a combined analytical and simulation approach for their performance and energy consumption evaluation. We demonstrate that the proposed HOS data center network achieves high performance and flexibility while considerably reducing the energy consumption of current solutions. [ABSTRACT FROM AUTHOR]

Hybrid optical switching (HOS) has the potential to provide highly efficient operation through combining various switching paradigms and different implementation options within the same network. The flexibility of choosing between circuit, packet or burst switching and electronic or optical implementation results in an improvement of both energy and data transport efficiency because the most appropriate method and less power consuming elements can be selected and used for transmission of data through the network while temporarily inactive elements are switched off or put in a low-power mode. In this paper, we introduce a novel network concept that we refer to as adaptive hybrid optical switching (AHOS) and present and investigate several architectures and realization options for AHOS nodes. The corresponding control plane comprises two layers, of which one implements routing, signalling and link management functions as defined in the GMPLS standard while the other is responsible for managing already established circuits and scheduling the transmission of packets and bursts. We present results on both performance and energy consumption for different AHOS node realizations, network configurations and traffic patterns, which prove the potential for a high improvement in energy efficiency with respect to conventional electronic packet-switched networks. [ABSTRACT FROM AUTHOR]

Most Internet traffic is carried by the Transmission Control Protocol (TCP) nowadays, even in the case of real-time services. Detecting and mitigating the congestion is one of the primary tasks of this protocol, in fact, different TCP versions are defined by their congestion control algorithms. Furthermore, Active Queue Management (AQM) algorithms share the same goal of congestion mitigation with TCP; in particular, the most efficient congestion control occurs when AQM and TCP work together. This paper presents a brief survey and a cross-comparison of the latest and most important TCP and AQM variants, then provides an evaluation of a different kind of performance on the ns-3 network simulator over various types of environments (multiple Round Trip Time, long delay, different congestion levels, etc.). In any shared bottleneck, the choice of the TCP-AQM couple to adopt is crucial. We will show that the results are not univocal and the "one size fits all" solution does not exist. Moreover, the proper couple depends on the performance that we want to boost and on the environment that we have to deal with. [ABSTRACT FROM AUTHOR]