Search results for "Local area network"
showing 10 items of 47 documents
A software tool to acquire, synchronise and playback multimedia data: an application in kinesiology
2000
Assessing the physical condition of the human body frequently requires evaluating different tests performed by different devices. This information has to be analysed simultaneously to derive conclusions, and so a temporal relationship must be established between the data sources. In this paper, synchronisation of the sources of information is achieved by synchronising the clocks of computers connected in a Local Area Network. A clock synchronisation protocol is used and a global time is stamped in each information data flow. During analysis, the time-stamp is used to playback the data in a synchronised way. The proposed system is valid for any medical application in which data synchronisati…
Remote programming of network robots within the UJI Industrial Robotics Telelaboratory: FPGA vision and SNRP network protocol
2009
This paper presents the UJI Industrial Robotics Telelaboratory, which lets Ph.D. and Master’s degree students perform robotics and computer vision tele-experiments. By using this system, students are able to program experiments remotely via the Web, in order to combine the use of a field-programmable gate array (FPGA) to provide real-time vision processing, a conveyor belt, and a Motoman industrial manipulator. This paper introduces the novel SNRP protocol (i.e., Simple Network Robot Protocol), which permits the integration of network robots and sensors within an e-learning platform in a simple and reliable manner. As long as the students are able to interact remotely with a real robotic sc…
Multiservice Optical Fibre Local Area Networks For Data Transmission And Telemetry In The Electric Power Industry
1986
The paper contains a review of a few of experimental optical fibre multiservice and multibranch local area networks /LANs/. Systems accomplish transmission, distribution and processing of analog or digital signals from numerous sources or measurement terminals. The authors put stress also on the possibility of combining transmission properties of fiber optic networks with fibre optic sensors. Several construction problems and chosen properties of multiport /multiterminal/ optical buses /networks/ have been considered. All examination systems of optical fibre LANs are discussed in respect of application them as telemetric, transmission, telesignaling and telecontrol systems for the power ele…
CVS: Using VLANs to Counteract the Effect of Topology Changes in Quasi-Static Mesh Access Networks
2006
Mesh networks are candidate to play the role of switched Ethernet LANs over extended areas and with a sensibly higher flexibility. Actually, mesh networks can exploit both Ethernet and wireless technologies, e.g. Wi-Fi and/or free-space optical links, to provide a high degree of redundancy in an access network, and to provide users with powerful means to connect with each other. By using such technologies, the mesh topology remains stable for hours, so that the mesh topology can be considered quasi-static. However, large meshes require a heavy overhead in the network control plane as for the management of end-to-end paths, which can change due to mobility of users and due to occasional fail…
Dynamic QoS management for multimedia real-time transmission in industrial environments
2007
The use of multimedia within industrial applications has become commonplace, targetting improved process monitoring and machine vision. In both cases, the multimedia information is commonly distributed and subject to time constraints that must be met across networks while avoiding untolerable interference over typical control flows. This can be achieved with Constant Bit-Rate (CBR) channels, typically supported by real-time protocols. However, the compressors used to reduce the amount of information to transfer generate Variable Bit-Rate (VBR) patterns. Adapting a VBR source to a CBR channel requires specific care in order to avoid wasting channel bandwidth or dropping video frames. This pa…
An evaluation of switched ethernet and linux traffic control for real-time transmission
2008
Switched Ethernet networks are spreading to industrial environments more are more. The current trend is using them at all levels of a factory, replacing this way field-buses and other industrial networks. Switched Ethernet lacks the drawback of the non-deterministic collision resolution of coax cabling. However there are still some sources of indeterminism, mostly due to contention problems in message queues at switches and network interfaces. These problems can be dealt with using traffic control mechanisms for packet prioritisation and scheduling. These features have been largely inaccessible in Ethernet for a long time but, nowadays, they are widely available in industrial switches and a…
Design of an exact data deduplication cluster
2012
Data deduplication is an important component of enterprise storage environments. The throughput and capacity limitations of single node solutions have led to the development of clustered deduplication systems. Most implemented clustered inline solutions are trading deduplication ratio versus performance and are willing to miss opportunities to detect redundant data, which a single node system would detect. We present an inline deduplication cluster with a joint distributed chunk index, which is able to detect as much redundancy as a single node solution. The use of locality and load balancing paradigms enables the nodes to minimize information exchange. Therefore, we are able to show that, …
Gigabit Ethernet backbones with active loops
2001
The current standard Ethernet switches are based on the Spanning Tree (ST) protocol. Their most important restriction is that they can not work when the topology has active loops. In fact, the ST protocol selects a tree from the real topology by blocking the links that are not involved in the tree. This restriction produces a network traffic unbalancing behavior saturating those link near the root switch while rest of links will be idle or with a very low utilization. This paper proposes a new transparent switch protocol for Gigabit Ethernet backbones that considerably improves the performance of current ones. The proposed protocol is named ALOR for Active Loops and Optimal Routing. ALOR pr…
A fault-tolerant protocol for railway control systems
2006
Railway control systems are largely based on data communication and network technologies. With the adoption of Ethernet-IP as the main technology for building end-to-end real-time networks on railway control systems, the requirement to deliver high availability, quality and secure services over Ethernet has become strategic. Critical real-time traffic is generally penalized and the maximum restoration time of 50 msec sometimes is exceeded because of real-time applications hangings, so passengers' safety could be committed. It occurs on more than twenty percent of critical fail tests performed. Our main goal is to minimize restoration time from the application point of view. This article des…
SmartARP: merging IP and MAC addressing for low-cost gigabit Ethernet networks
1999
Abstract Address Resolution Protocol (ARP) is one of the key TCP/IP stack protocols, used on LANs to map 32 bit IP addresses into 48 bit hardware addresses. Regular ARP uses MAC layer broadcasts to perform the mapping. In this paper a new server-based ARP extension (smartARP) is proposed, which allows the extension of ARP functionality beyond a single MAC layer broadcast domain. Compared to regular IP router, smartARP together with simple broadcast-filtering switches presents a low-cost alternative for forwarding packets between MAC layer broadcast domains. SmartARP is transparent to existing IP hosts, operates independent of LAN speed, and scales for big networks.