Search results for "computer networks"
showing 10 items of 860 documents
Algorithmic Complexity Vulnerability Analysis of a Stateful Firewall
2016
Algorithmic complexity vulnerabilities are an opportunity for an ad-versary to conduct a sophisticated kind of attack i.e. on network infrastructure services. Such attacks take advantage of worst case time or space complexity of algorithms implemented on devices in their software. In this paper we address potential risks introduced by such algorithmic behavior in computer networks in particular on a stateful firewall. First we introduce the idea and theoretical background for the attack. We then describe in full detail a successfully con-ducted attack which takes advantage of the worst case computational complexi-ty of O(n2) of a hash table data structure used to store active sessions. The …
A TDMA-Based MAC Protocol Supporting Cooperative Communications in Wireless Mesh Networks
2011
This paper proposes a TDMA-based medium access control protocol which enables cooperative communications in multi-hop wireless mesh networks. According to the proposed scheme, each router at the two-hop neighbourhood of each other is allocated to a specific time slot for accommodating either direct or cooperative transmissions in a coordinated manner, controlled by mini-slots which are part of the time slot. Benefiting from the elaborate mini-slot design, channel resources are fairly and efficiently allocated to each router so that no handshake is needed prior to each packet transmission. By providing access priority to cooperative transmission through an optimal relay which is determined b…
Computer networks stability independence of the queuing delays
2015
Communication in intelligent computer networks is an indispensible attribute of the dataflow quality in Web traffic. We propose a model that investigates intelligent computer networks stability while specifying its limits. Packet queuing delay affects the performance of the network, and especially its stability. If the network is presented as a dynamic system in block diagram form, we compute a transfer function and determine the quasi-polynomial system. The characteristic polynomial distribution of zeros of complex variable quasi-plane determines the boundaries of the network stability. The approach relies on estimation of the network system's transfer functions and its quasi-polynomial. C…
Endpoint Admission Control with Delay Variation Measurements for QoS in IP Networks.
2002
In this paper we describe a novel Endpoint Admission Control scheme (EAC) for IP telephony. EAC mechanisms are driven by independent measurements taken by the edge nodes on a flow of packets injected in the network to probe the source to destination path. Our scheme is characterized by two fundamental features. First, it does not rely on any additional procedure in internal network routers other than the capability to apply different service priorities to probing and data packets. Second, the connection admission decision is based on the analysis of the probing flow delay variation statistics. Simulation results, which focus on a IP telephony scenario, show that, despite the lack of core ro…
A reconfigurable platform for evaluating the performance of QoS networks
2010
Nowadays, high performance System and Local Area Networks (SAN/LAN) have to serve heterogeneous traffic consisting of information flows with different bandwidth and latency requirements. This makes it necessary to provide Quality of Service (QoS) and optimize the design of network components. In this paper we present a hardware tool designed to analyze the performance of QoS networks, under given traffic conditions and server models. In particular, a reprogrammable multimedia traffic Generator/Monitor platform has been built. This permits prototyping the communication system of a high speed LAN/SAN on a single FPGA device. Hence, it can be used at design to produce more efficient devices. T…
A new Scheme for RPL to handle Mobility in Wireless Sensor Networks
2017
Mobile wireless sensor networks (WSNs) are characterised by dynamic changes in the network topology leading to route breaks and disconnections. The IPv6 routing protocol for low power and lossy networks (RPL), which has become a standard, uses the Trickle timer algorithm to handle changes in the network topology. However, neither RPL nor Trickle timer are well adapted to mobility. This paper investigates the problem of supporting mobility when using RPL. It enhances RPL to fit with sensors' mobility by studying two cases. Firstly, it proposes to modify RPL in order to fit with a dynamic and hybrid topology in the context of medical applications. Secondly, it investigates a more general case…
Adaptive live video streaming on low-cost wireless multihop networks for road traffic surveillance in smart cities
2021
Abstract Traffic surveillance is an important issue for Intelligent Transportation Systems (ITS) that helps detect incidents automatically, such as wrong-way drivers, still-standing vehicles and jams. Sometimes these systems require a fast and short-term deployment of video cameras. In these cases, ad-hoc networks could be a low-cost and feasible option, but they have poor performance for video delivery. Thus, we propose a smart live video adaptive streaming technique in order to transport video streams from the cameras to the external road traffic monitoring servers. To achieve this goal, these networks need a thorough study in order to analyze video quality under their inherent constraint…
Cooperative layer-2 based routing approach for hybrid wireless mesh networks
2013
In a Wireless Mesh Network (WMN), the convenience of a routing strategy strongly depends on the mobility of the intermediate nodes that compose the paths. Taking this behaviour into account, this paper presents a routing scheme that works differently accordingly to the node mobility. In this sense, a proactive routing scheme is restricted to the backbone to promote the use of stable routes. Conversely, the reactive protocol is used for searching routes to or from a mobile destination. Both approaches are simultaneously implemented in the mesh nodes so that the routing protocols share routing information that optimises the network performance. Aimed at guaranteeing the IP compatibility, the …
A dynamic multi-sink routing protocol for static and mobile self-organizing wireless networks: A routing protocol for Internet of Things
2021
Abstract With the rapid advent of using various devices like smart phones, vehicles etc, the connection of these devices with the help of Internet connectivity has emerged to IoT paradigm. The interconnection of smart objects under the various real world constraints like communication technologies, network scalability, node mobility, energy consumption etc, is a big challenge and requires designing new robust, adaptive, dynamic, and configurable routing protocols. With the arrival of the 5G and the future Internet, the latency time will be extremely reduced, this motivated us to propose a new protocol that entrust internet to transport a large part of control and data traffic of the network…
SDN controllers security issues
2017
Software-Defined Networking (SDN) is essentially varying the way we design and manage networks, which makes a communication network programmable. In SDN, a logically centralized controller has straight control over the packet-handling functions of the network switches, using a standard, open API (Application Programming Interface) such as OpenFlow. OpenFlow is a broadly used protocol for software-defined networks (SDNs) that presents a new model in which the control plane is inattentive from the forwarding plane for the network devices. In SDN approach centralized entities called "controllers" perform like network operating systems run dissimilar applications that accomplish and control the…