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Wireless Network Protocols
Published in Jerry D. Gibson, Mobile Communications Handbook, 2017
Renato Mariz de Moraes, Hamid R. Sadjadpour
DSR employs the source routing feature in which the entire route is part of the header of the packet and utilizes caches to store routes on nodes. Consequently, if a node A needs to send a packet to another node B, but it does not have a route to B, then node A initiates a route discovery and broadcasts (floods) an RREQ message. The RREQ packet contains the sender's address, the destinations address, and a unique request identification (ID) determined by sender A. Each node that receives the RREQ message, appends its own identifier (ID), and forwards the updated RREQ. Eventually, an RREQ will reach the destination node with complete reverse path to source which allows the destination to unicast an RREP back to the source establishing the route. After that, the source can unicast the data packet to destination in which the packet header contains the entire path to destination being forwarded by each node along the route.
Mobile Ad Hoc Networks: Rapidly Deployable Emergency Communications
Published in Nazmul Siddique, Syed Faraz Hasan, Salahuddin Muhammad Salim Zabir, Opportunistic Networking, 2017
Transport protocols usually experience a drop in throughput when the nodes move with high mobility. In this kind of situation, TCP behaves differently depending on the routing protocols it uses. Figure 3.13 shows that at a lower speed the TCP–AODV pair performed better than the TCP–DSR and TCP–OLSR pairs. This is because OLSR is a proactive routing protocol that finds a path based on previously obtained information. As a result, in the event of path failure it cannot find a new path quickly. DSR is a proactive protocol, but it also uses some previously saved route caches to find paths between two end nodes. By contrast, AODV is a reactive and on-demand routing protocol that quickly recovers path failure. Because TCP performance over wireless networks is closely related to path failure [19], AODV served better than the other two pairs. Nevertheless, the performance of the TCP–AODV pair degraded at a higher speed (after 10 m/s) compared to that of the TCP–DSR pair. This is because at a higher speed, in the event of path failure, the DSR route cache frequently serves better than finding a new path.
Power Adjusting Algorithm on Mobility Control for Mobile Ad Hoc Networks
Published in Liansheng Tan, Resource Allocation and Performance Optimization in Communication Networks and the Internet, 2017
The recently reactive routing protocols designed for wireless ad hoc network include the notable DSR protocol [416] and Ad hoc On-Demand Distance Vector Routing (AODV) protocol [417]. DSR is a routing protocol for wireless ad hoc networks. This protocol uses source routing, in which all the routing information is maintained and dynamically updated at mobile nodes. It has two major phases, namely, route discovery and route maintenance. These two functions work together to enable any host in the ad hoc network to dynamically discover and maintain a route to any other host in the network. The source broadcasts a Route Request (RREQ) message to find a route, Route Reply (RREP) is then generated if the message has reached the intended destination node. AODV builds routes using a route request and route reply query cycle. When a source node desires a route to a destination for which it does not already have a route, it broadcasts an RREQ packet across the network. A node receiving the RREQ may unicast an RREP back to its source or rebroadcasts the RREQ depending on if it is the destination or not. Nodes keep track of the RREQ source IP address and broadcast ID. As the RREP propagates back to the source, nodes set up forward pointers to the destination. Once the source node receives the RREP, it may begin to forward data packets to the destination.
Quality of service assessment routing protocols for performance in a smart building: A case study
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2022
The process of operation in the DSR protocol is that the node is allowed to dynamically specify a path between multiple networks jumps through which it can send data to the D. In this protocol, the route of some D points is specified only when that node sends a request. In this case, it must have information about the desired route and D. In the routing process in this protocol, each packet has a complete and regular list of nodes that it must pass through. One of the features of the DSR routing protocol is that it does not utilize any periodic routing messages, thus reducing network bandwidth slag, also conserving battery power, and preventing the generation of numerous routing updates across the network. Routing in this protocol is based on the method provided by the MAC layer (Araujo, Gomes, and Rocha 2020; Khudayer et al. 2020). Each packet must have a full address of each jump from S to D that is not effective on big networks. Therefore, the amount of slag and bandwidth consumption grows significantly with enhancing the diameter of the network. Generally, we have two main user models under the DSR routing protocol which are:
A Modified DSR Protocol Using Deep Reinforced Learning for MANETS
Published in IETE Journal of Research, 2023
Based on our study from all related works, we propose a novel model to improve a traditional DSR routing algorithm using a deep reinforced learning technique. DSR protocol involves two stages: route discovery and route maintenance. The performance enhancement of the MANET is always based on its ability to re-establish the path in the case of local route failure and path unavailability. The traditional DSR re-establishes new paths during path failures in its route maintenance stage. But we propose a model where instead of choosing a random new path, an optimal path is identified and readily available to handle such routing errors. The workflow of the proposed model is explained in the next section.