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Real-Time Ethernet for Automation Applications
Published in Richard Zurawski, Networked Embedded Systems, 2017
In a SERCOS system, there is always a master station as a controlling device and one or up to 254 slave devices as axis controllers each with two Ethernet ports. The basic network topology can be either a daisy-chain (line structure) or a ring (ring structure). General use switches are not permitted between any two participants. Only the free port of the last slave in a line structure may be connected to a switch if required by the configuration, e.g., for communication with devices via TCP/IP or UDP/UDP.
Introduction to Data Communications and Networking
Published in Mário Marques da Silva, Cable and Wireless Networks, 2018
A network topology is the arrangement of the devices within a network. The topology concept is applicable to a LAN, a MAN, or a WAN. In the case of a LAN, such a topology refers to the way hosts and servers are linked together, while in the MAN and WAN cases, this refers to the way nodes (routers) are linked together. For the sake of simplicity, this description refers to hosts and servers (in the case of LAN) and nodes (in the case of MAN and WAN) just as hosts.†
Research on the Zigbee routing algorithm based on link availability prediction
Published in Lin Liu, Automotive, Mechanical and Electrical Engineering, 2017
Zigbee is a low-power, low-cost and good reliability wireless network technology featuring with little delay and large network capacity (Baront P & Pillai P & Chook V W C, 2007; Ren Xiuli & Yu Haibin, 2007). Presently it is mainly used in medical, mineral, environmental testing and military areas. IEEE 802.15.4 protocol standard is adopted in the physical layer and MAC layer of wireless sensor network. There are three types of network topology: star, tree and mesh (Ma Haichao, 2014; Chakeres I D, 2002). The network layer mainly adopts Cluster-Tree routing Algorithm and AODVjr routing algorithm, and cluster-Tree routing algorithm is based on the parent-child relationship between nodes in the tree structure. Data packets need to be forwarded according to the parent-child relationship between nodes, and the routing method need not to store the routing table, which is the static route. Through AODVjr routing algorithm (Zhang Fenghui & Zhou Huiling, 2009) the optimal path between the source node and the destination node could be found. The node route discovery process sends the RREQ message to set up the route through the broadcast packet. The node energy depends on the battery. Most of the communication overheads for packet forwarding between nodes, due to the limited overall energy of the network, especially at the upper nodes near the coordinator, the energy consumption of the nodes increases with the running time of the network, which leads to interruption of the network link. AODVjr routing algorithm using local repair mechanism, the fault node to restart a route discovery process by broadcasting RREQ data packets to find a new route (Ren Weil & Yeung D.Y, 2006). The local route repair process initiates from the downstream node automatically, and the link disconnection leads to the loss of the node data. Therefore, the link availability prediction is very important to guarantee the normal link communication.
Wireless body area networks: a comprehensive survey
Published in Journal of Medical Engineering & Technology, 2020
Bahae Abidi, Abdelillah Jilbab, El Haziti Mohamed
The network topology is the organisation of the network, including the connecting lines and all its nodes. It is one of the major problems of the conception of the body sensor network. It influences the functional performance of the system like routing protocols, energy consumption, traffic load and node robustness. The network topology is categorised into two topologies concerning the concept of the hop: the single hop topology where sensor nodes can communicate directly with the base station, which means all sensors node are one hop away from the base station and multi-hop topology where the sensed data will reach the base station through one or more biosensors. The research was done to examine the reliability of multi-hop and single hop topology. Packet delivery ratio was used as metric to measure the reliability and it was found from their results that the multi-hop topology is much reliable than single hop topology [14].
Wearable electronic textiles
Published in Textile Progress, 2019
David Tyler, Jane Wood, Tasneem Sabir, Chloe McDonnell, Abu Sadat Muhammad Sayem, Nick Whittaker
Network topology within SeCS and IoT refers to how computers, devices, sensors, actuators, gateways and other devices connect together, together with the layout of communications, routing paths and devices on a network. Network topology describes how computers, routers, switches, printers and other devices are connected. The topology describes the routing and layout of wires and devices on a network. In order to decide the best network topology for the SeCS or IoT system, it is necessary to understand the relative advantages and disadvantages of the various network topologies [205]. In some case, sensor networks may be “off grid” and not transmit their data to users beyond the local aggregation or collection point, such as a PC or smart phone. This topology for the sensor network depends on the system application. For example, a personal area network (PAN) may transmit sensor data to a single central point (star topology). Other networks, such as home environment monitoring, may employ a mesh topology, which can help when routes of communication may be fallible [206].