The document discusses on-demand driven reactive routing protocols. It provides an overview of table-driven vs on-demand routing protocols and describes two popular on-demand protocols - Dynamic Source Routing (DSR) and Ad Hoc On-Demand Distance Vector Routing (AODV) in detail. DSR uses source routing by adding the complete route to packet headers. AODV maintains routing tables at nodes and relies on dynamically establishing next hop information for routes.
Routing protocols for ad hoc wireless networks Divya Tiwari
The document discusses routing protocols for ad hoc wireless networks. It outlines several key challenges for these protocols, including mobility, bandwidth constraints, error-prone shared wireless channels, and hidden/exposed terminal problems. It also categorizes routing protocols based on how routing information is updated (proactively, reactively, or through a hybrid approach), whether they use past or future temporal network information, the type of network topology supported (flat or hierarchical), and how they account for specific resources like power.
LAR utilizes location information to improve routing efficiency by reducing control overhead. It uses GPS to obtain geographical information. There are two zones in LAR - the ExpectedZone where the destination is expected to be, and the RequestZone which is the area where routing packets can propagate. PAR aims to minimize energy consumption per packet by calculating the sum of energy required at each hop. It also aims for maximum network connectivity and uniform distribution of power consumption across all nodes.
ZRP divides routing into intrazone and interzone routing. Intrazone routing uses a proactive approach to route packets within a node's routing zone. Interzone routing uses a reactive approach where the source node sends route requests to peripheral nodes when the destination is outside its zone. The optimal zone radius depends on factors like mobility and query rates, with smaller radii preferred for higher mobility. ZRP aims to reduce routing overhead through techniques like restricting floods and maintaining multiple routes.
This document discusses different types of routing protocols for mobile ad hoc networks. It begins by classifying routing protocols into four categories: proactive (table-driven), reactive (on-demand), hybrid, and geographic location-assisted. It then provides more details on proactive protocols like DSDV, and reactive protocols like DSR and AODV. For DSDV, it describes how routing tables are regularly exchanged and updated when link breaks occur. For DSR and AODV, it explains how routes are discovered on-demand via route requests and replies. Key differences between DSR and AODV are also summarized.
Lecture 19 22. transport protocol for ad-hoc Chandra Meena
This document discusses transport layer protocols for mobile ad hoc networks (MANETs). It begins with an introduction to MANETs and the need for new network architectures and protocols to support new types of networks. It then provides an overview of TCP/IP and how TCP works, including congestion control mechanisms. The document discusses challenges for TCP over wireless networks, where packet losses are often due to errors rather than congestion. It covers different versions of TCP and their approaches to congestion control. The goal is to design transport layer protocols that can address the unreliable links and frequent topology changes in MANETs.
The document discusses several routing protocols for mobile ad hoc networks:
- DSR allows nodes to cache and share routing information for more efficient routing but has larger packet headers due to source routing. AODV uses only next hop information, keeping routing tables smaller.
- Both protocols use route discovery and maintenance, but AODV proactively refreshes routes while DSR reacts to failures. AODV also uses sequence numbers to prevent loops and choose fresher routes.
- Overall, DSR is better for networks where routes change infrequently while AODV scales better and maintains only active routes, at the cost of higher routing overhead during route discovery. Security remains a challenge for both protocols.
Routing protocols in wireless sensor networks face several unique challenges compared to other wireless networks. The document discusses these challenges and provides an overview of common routing protocol approaches in WSNs, including flat routing protocols like SPIN and Directed Diffusion, hierarchical routing protocols like LEACH, and location-based routing protocols. It also covers routing design issues specific to WSNs such as energy efficiency, data delivery models, fault tolerance, and quality of service.
Routing protocols for ad hoc wireless networks Divya Tiwari
The document discusses routing protocols for ad hoc wireless networks. It outlines several key challenges for these protocols, including mobility, bandwidth constraints, error-prone shared wireless channels, and hidden/exposed terminal problems. It also categorizes routing protocols based on how routing information is updated (proactively, reactively, or through a hybrid approach), whether they use past or future temporal network information, the type of network topology supported (flat or hierarchical), and how they account for specific resources like power.
LAR utilizes location information to improve routing efficiency by reducing control overhead. It uses GPS to obtain geographical information. There are two zones in LAR - the ExpectedZone where the destination is expected to be, and the RequestZone which is the area where routing packets can propagate. PAR aims to minimize energy consumption per packet by calculating the sum of energy required at each hop. It also aims for maximum network connectivity and uniform distribution of power consumption across all nodes.
ZRP divides routing into intrazone and interzone routing. Intrazone routing uses a proactive approach to route packets within a node's routing zone. Interzone routing uses a reactive approach where the source node sends route requests to peripheral nodes when the destination is outside its zone. The optimal zone radius depends on factors like mobility and query rates, with smaller radii preferred for higher mobility. ZRP aims to reduce routing overhead through techniques like restricting floods and maintaining multiple routes.
This document discusses different types of routing protocols for mobile ad hoc networks. It begins by classifying routing protocols into four categories: proactive (table-driven), reactive (on-demand), hybrid, and geographic location-assisted. It then provides more details on proactive protocols like DSDV, and reactive protocols like DSR and AODV. For DSDV, it describes how routing tables are regularly exchanged and updated when link breaks occur. For DSR and AODV, it explains how routes are discovered on-demand via route requests and replies. Key differences between DSR and AODV are also summarized.
Lecture 19 22. transport protocol for ad-hoc Chandra Meena
This document discusses transport layer protocols for mobile ad hoc networks (MANETs). It begins with an introduction to MANETs and the need for new network architectures and protocols to support new types of networks. It then provides an overview of TCP/IP and how TCP works, including congestion control mechanisms. The document discusses challenges for TCP over wireless networks, where packet losses are often due to errors rather than congestion. It covers different versions of TCP and their approaches to congestion control. The goal is to design transport layer protocols that can address the unreliable links and frequent topology changes in MANETs.
The document discusses several routing protocols for mobile ad hoc networks:
- DSR allows nodes to cache and share routing information for more efficient routing but has larger packet headers due to source routing. AODV uses only next hop information, keeping routing tables smaller.
- Both protocols use route discovery and maintenance, but AODV proactively refreshes routes while DSR reacts to failures. AODV also uses sequence numbers to prevent loops and choose fresher routes.
- Overall, DSR is better for networks where routes change infrequently while AODV scales better and maintains only active routes, at the cost of higher routing overhead during route discovery. Security remains a challenge for both protocols.
Routing protocols in wireless sensor networks face several unique challenges compared to other wireless networks. The document discusses these challenges and provides an overview of common routing protocol approaches in WSNs, including flat routing protocols like SPIN and Directed Diffusion, hierarchical routing protocols like LEACH, and location-based routing protocols. It also covers routing design issues specific to WSNs such as energy efficiency, data delivery models, fault tolerance, and quality of service.
This document summarizes geographical routing in wireless sensor networks. It begins with an introduction to geographic routing protocols, which route packets based on the geographic position of nodes rather than their network addresses. It then discusses several specific geographic routing protocols, including Greedy Perimeter Stateless Routing (GPSR) and Geographical and Energy Aware Routing (GEAR). The document also covers topics like how nodes obtain location information, security issues in geographic routing like the Sybil attack, and concludes that geographic routing can enable scalable and energy-efficient routing in wireless sensor networks.
Directed diffusion for wireless sensor networkingHabibur Rahman
This document summarizes the key ideas of the "Directed Diffusion for Wireless Sensor Networking" paper. It introduces directed diffusion as a data-centric paradigm for wireless sensor networks that is designed for robustness, scalability, and energy efficiency. The core concepts of directed diffusion are interests, data, gradients, and reinforcement, which work together to efficiently route queries to sensor data in the network. Through localized interactions and data aggregation, directed diffusion is shown to significantly reduce energy consumption compared to flooding-based approaches in wireless sensor networks.
This document summarizes several reactive routing protocols for mobile ad hoc networks (MANETs). Reactive protocols create routes only when needed by a source. Dynamic Source Routing uses route requests and replies to find paths, while Temporally-Ordered Routing Algorithm builds and maintains a directed acyclic graph rooted at destinations. Some protocols aim to improve quality of service or support real-time data streams through techniques like bandwidth estimation and mobility prediction. Source Routing with Local Recovery reduces overhead by allowing intermediate nodes to perform local error recovery using route caches when possible.
Mac protocols for ad hoc wireless networks Divya Tiwari
The document discusses MAC protocols for ad hoc wireless networks. It addresses key issues in designing MAC protocols including limited bandwidth, quality of service support, synchronization, hidden and exposed terminal problems, error-prone shared channels, distributed coordination without centralized control, and node mobility. Common MAC protocol classifications and examples are also presented, such as contention-based protocols, sender-initiated versus receiver-initiated protocols, and protocols using techniques like reservation, scheduling, and directional antennas.
Proactive routing protocol
Each node maintain a routing table.
Sequence number is used to update the topology information
Update can be done based on event driven or periodic
Observations
May be energy expensive due to high mobility of the nodes
Delay can be minimized, as path to destination is already known to all nodes.
This document provides an overview of routing protocols in ad hoc networks. It begins with an abstract describing the objectives of surveying and comparing different classes of ad hoc routing protocols. The document then outlines the topics to be covered, including the characteristics, applications, and types of ad hoc routing protocols. Several representative routing protocols are described in detail, including table-driven, hybrid, source-initiated, location-aware, multipath, hierarchical, multicast, and power-aware protocols. The document concludes by discussing future work related to improving reusability and security of ad hoc routing protocols.
The document discusses schedule-based MAC protocols for wireless sensor networks. It begins with a review of previous concepts and then discusses key schedule-based protocols including LEACH, SPIN, S-MAC, and TRAMA. The document emphasizes that schedule-based protocols explicitly assign transmission timeslots to nodes to avoid collisions and allow nodes to sleep at other times, reducing idle listening and improving energy efficiency compared to contention-based protocols. Time synchronization is necessary for schedule-based protocols to function properly.
Mobile Network Layer protocols and mechanisms allow nodes to change their point of attachment to different networks while maintaining ongoing communication. Key concepts include:
- Mobile IP adds mobility support to IP, allowing nodes to use the same IP address even when changing networks. It relies on home agents and care-of addresses.
- Registration allows mobile nodes to inform their home agent of their current location when visiting foreign networks. Tunneling and encapsulation techniques are used to forward packets to mobile nodes' current locations.
- Various routing protocols like DSDV have been developed for mobile ad hoc networks which have no fixed infrastructure and dynamic topologies.
The document discusses key issues in designing ad hoc wireless routing protocols including mobility, bandwidth constraints from a shared radio channel, and resource constraints of battery life and processing power. It outlines problems like the hidden and exposed terminal problems that can occur on a shared wireless channel. It also provides ideal characteristics for routing protocols, noting they should be fully distributed, adaptive to topology changes, use minimal flooding, and converge quickly when paths break while minimizing overhead through efficient use of bandwidth and resources.
This document discusses clustering-based ad hoc routing protocols. It introduces the Clusterhead Gateway Switch Routing (CSGR) protocol, which uses a hierarchical network topology with mobile nodes grouped into clusters led by cluster heads. Each node maintains a cluster member table mapping nodes to cluster heads and a routing table to select the next hop towards the destination cluster head. The Least Cluster Change algorithm aims to minimize changes to cluster heads. The document provides an example routing from node 1 to node 12 and compares CSGR to the table-driven DSDV protocol.
The document discusses several MAC protocols for ad hoc networks including MACA, MACAW, and PAMAS. MACA uses RTS and CTS packets to avoid collisions but does not provide ACK. MACAW is a revision of MACA that includes ACK. It significantly increases throughput but does not fully solve hidden and exposed terminal problems. PAMAS uses a separate signaling channel for RTS-CTS and a data channel. It allows nodes to power down transceivers when not transmitting to save energy.
The network layer is responsible for routing packets from the source to destination. The routing algorithm is the piece of software that decides where a packet goes next (e.g., which output line, or which node on a broadcast channel).For connectionless networks, the routing decision is made for each datagram. For connection-oriented networks, the decision is made once, at circuit setup time.
Routing Issues
The routing algorithm must deal with the following issues:
Correctness and simplicity: networks are never taken down; individual parts (e.g., links, routers) may fail, but the whole network should not.
Stability: if a link or router fails, how much time elapses before the remaining routers recognize the topology change? (Some never do..)
Fairness and optimality: an inherently intractable problem. Definition of optimality usually doesn't consider fairness. Do we want to maximize channel usage? Minimize average delay?
When we look at routing in detail, we'll consider both adaptive--those that take current traffic and topology into consideration--and nonadaptive algorithms.
The document summarizes contention-based MAC protocols for wireless sensor networks. It discusses the PAMAS protocol, which provides detailed overhearing avoidance and uses two channels - a data channel and control channel. Signaling packets like RTS, CTS, and busy tones are transmitted on the control channel. It also covers concepts like low duty cycles, wake up mechanisms, and protocols like S-MAC that coordinate node schedules to reduce idle listening. Quizzes are included to test understanding of discussed concepts.
This document discusses and compares various routing protocols for mobile ad hoc networks (MANETs). It covers both topology-based approaches that rely on information about existing links, as well as position-based approaches where nodes determine their own position. Specific protocols discussed in detail include proactive protocols like Destination-Sequenced Distance-Vector (DSDV) and reactive protocols like Dynamic Source Routing (DSR). Hybrid protocols like Zone Routing Protocol (ZRP) that combine proactive and reactive approaches are also examined. The document provides illustrations and comparisons of the routing mechanisms and characteristics of these important MANET routing protocols.
This document discusses mobility management in mobile ad-hoc networks (MANETs). It begins by introducing MANETs and explaining that they are temporary networks formed spontaneously via wireless communication between mobile nodes without centralized administration. It then discusses the need for mobility management, including location management and handoff management routing protocols. It also discusses different types of node mobility and mobility models for predicting node movement patterns over time in MANETs. The document categorizes mobility models as trace-based (using real movement data) or synthetic-based (simulating realistic movement), and lists examples of models within each category like the random waypoint and reference point group mobility models.
How to put these nodes together to form a meaningful network.
How a network should function at high-level application scenarios .
On the basis of these scenarios and optimization goals, the design of networking protocols in wireless sensor networks are derived
A proper service interface is required and integration of WSNs into larger network contexts.
Global State Routing (GSR) maintains a global knowledge of network topology like link state routing but avoids inefficient flooding. Each node periodically exchanges its link state table only with neighbors, not the entire network. This reduces overhead compared to link state routing. GSR nodes use Dijkstra's algorithm on the accumulated link state information to compute optimal paths locally without global flooding.
This document discusses the origins and development of ad hoc networks. It describes how packet radio networks (PRNETs) in the 1970s, developed by DARPA, were the first generation of ad hoc networks. PRNETs used multi-hop routing between mobile radio terminals and packet radios to communicate without fixed infrastructure. The document outlines the key components and routing techniques of PRNETs, including point-to-point and broadcast routing. It also discusses how subsequent generations in the 1980s-1990s focused on improving performance, scalability, and developing commercial applications like Bluetooth.
Lecture 7 8 ad hoc wireless media access protocolsChandra Meena
1) The document discusses issues with media access control (MAC) protocols in ad hoc wireless networks, including problems like hidden terminals and exposed nodes.
2) It classifies MAC protocols as synchronous, asynchronous, receiver-initiated, or sender-initiated. The RTS-CTS handshake is presented as a solution to the hidden terminal problem.
3) However, the RTS-CTS approach has shortcomings like collisions when RTS and CTS messages are sent by different nodes or when multiple CTS messages are granted. Solutions to the exposed node problem are also discussed.
This document summarizes geographical routing in wireless sensor networks. It begins with an introduction to geographic routing protocols, which route packets based on the geographic position of nodes rather than their network addresses. It then discusses several specific geographic routing protocols, including Greedy Perimeter Stateless Routing (GPSR) and Geographical and Energy Aware Routing (GEAR). The document also covers topics like how nodes obtain location information, security issues in geographic routing like the Sybil attack, and concludes that geographic routing can enable scalable and energy-efficient routing in wireless sensor networks.
Directed diffusion for wireless sensor networkingHabibur Rahman
This document summarizes the key ideas of the "Directed Diffusion for Wireless Sensor Networking" paper. It introduces directed diffusion as a data-centric paradigm for wireless sensor networks that is designed for robustness, scalability, and energy efficiency. The core concepts of directed diffusion are interests, data, gradients, and reinforcement, which work together to efficiently route queries to sensor data in the network. Through localized interactions and data aggregation, directed diffusion is shown to significantly reduce energy consumption compared to flooding-based approaches in wireless sensor networks.
This document summarizes several reactive routing protocols for mobile ad hoc networks (MANETs). Reactive protocols create routes only when needed by a source. Dynamic Source Routing uses route requests and replies to find paths, while Temporally-Ordered Routing Algorithm builds and maintains a directed acyclic graph rooted at destinations. Some protocols aim to improve quality of service or support real-time data streams through techniques like bandwidth estimation and mobility prediction. Source Routing with Local Recovery reduces overhead by allowing intermediate nodes to perform local error recovery using route caches when possible.
Mac protocols for ad hoc wireless networks Divya Tiwari
The document discusses MAC protocols for ad hoc wireless networks. It addresses key issues in designing MAC protocols including limited bandwidth, quality of service support, synchronization, hidden and exposed terminal problems, error-prone shared channels, distributed coordination without centralized control, and node mobility. Common MAC protocol classifications and examples are also presented, such as contention-based protocols, sender-initiated versus receiver-initiated protocols, and protocols using techniques like reservation, scheduling, and directional antennas.
Proactive routing protocol
Each node maintain a routing table.
Sequence number is used to update the topology information
Update can be done based on event driven or periodic
Observations
May be energy expensive due to high mobility of the nodes
Delay can be minimized, as path to destination is already known to all nodes.
This document provides an overview of routing protocols in ad hoc networks. It begins with an abstract describing the objectives of surveying and comparing different classes of ad hoc routing protocols. The document then outlines the topics to be covered, including the characteristics, applications, and types of ad hoc routing protocols. Several representative routing protocols are described in detail, including table-driven, hybrid, source-initiated, location-aware, multipath, hierarchical, multicast, and power-aware protocols. The document concludes by discussing future work related to improving reusability and security of ad hoc routing protocols.
The document discusses schedule-based MAC protocols for wireless sensor networks. It begins with a review of previous concepts and then discusses key schedule-based protocols including LEACH, SPIN, S-MAC, and TRAMA. The document emphasizes that schedule-based protocols explicitly assign transmission timeslots to nodes to avoid collisions and allow nodes to sleep at other times, reducing idle listening and improving energy efficiency compared to contention-based protocols. Time synchronization is necessary for schedule-based protocols to function properly.
Mobile Network Layer protocols and mechanisms allow nodes to change their point of attachment to different networks while maintaining ongoing communication. Key concepts include:
- Mobile IP adds mobility support to IP, allowing nodes to use the same IP address even when changing networks. It relies on home agents and care-of addresses.
- Registration allows mobile nodes to inform their home agent of their current location when visiting foreign networks. Tunneling and encapsulation techniques are used to forward packets to mobile nodes' current locations.
- Various routing protocols like DSDV have been developed for mobile ad hoc networks which have no fixed infrastructure and dynamic topologies.
The document discusses key issues in designing ad hoc wireless routing protocols including mobility, bandwidth constraints from a shared radio channel, and resource constraints of battery life and processing power. It outlines problems like the hidden and exposed terminal problems that can occur on a shared wireless channel. It also provides ideal characteristics for routing protocols, noting they should be fully distributed, adaptive to topology changes, use minimal flooding, and converge quickly when paths break while minimizing overhead through efficient use of bandwidth and resources.
This document discusses clustering-based ad hoc routing protocols. It introduces the Clusterhead Gateway Switch Routing (CSGR) protocol, which uses a hierarchical network topology with mobile nodes grouped into clusters led by cluster heads. Each node maintains a cluster member table mapping nodes to cluster heads and a routing table to select the next hop towards the destination cluster head. The Least Cluster Change algorithm aims to minimize changes to cluster heads. The document provides an example routing from node 1 to node 12 and compares CSGR to the table-driven DSDV protocol.
The document discusses several MAC protocols for ad hoc networks including MACA, MACAW, and PAMAS. MACA uses RTS and CTS packets to avoid collisions but does not provide ACK. MACAW is a revision of MACA that includes ACK. It significantly increases throughput but does not fully solve hidden and exposed terminal problems. PAMAS uses a separate signaling channel for RTS-CTS and a data channel. It allows nodes to power down transceivers when not transmitting to save energy.
The network layer is responsible for routing packets from the source to destination. The routing algorithm is the piece of software that decides where a packet goes next (e.g., which output line, or which node on a broadcast channel).For connectionless networks, the routing decision is made for each datagram. For connection-oriented networks, the decision is made once, at circuit setup time.
Routing Issues
The routing algorithm must deal with the following issues:
Correctness and simplicity: networks are never taken down; individual parts (e.g., links, routers) may fail, but the whole network should not.
Stability: if a link or router fails, how much time elapses before the remaining routers recognize the topology change? (Some never do..)
Fairness and optimality: an inherently intractable problem. Definition of optimality usually doesn't consider fairness. Do we want to maximize channel usage? Minimize average delay?
When we look at routing in detail, we'll consider both adaptive--those that take current traffic and topology into consideration--and nonadaptive algorithms.
The document summarizes contention-based MAC protocols for wireless sensor networks. It discusses the PAMAS protocol, which provides detailed overhearing avoidance and uses two channels - a data channel and control channel. Signaling packets like RTS, CTS, and busy tones are transmitted on the control channel. It also covers concepts like low duty cycles, wake up mechanisms, and protocols like S-MAC that coordinate node schedules to reduce idle listening. Quizzes are included to test understanding of discussed concepts.
This document discusses and compares various routing protocols for mobile ad hoc networks (MANETs). It covers both topology-based approaches that rely on information about existing links, as well as position-based approaches where nodes determine their own position. Specific protocols discussed in detail include proactive protocols like Destination-Sequenced Distance-Vector (DSDV) and reactive protocols like Dynamic Source Routing (DSR). Hybrid protocols like Zone Routing Protocol (ZRP) that combine proactive and reactive approaches are also examined. The document provides illustrations and comparisons of the routing mechanisms and characteristics of these important MANET routing protocols.
This document discusses mobility management in mobile ad-hoc networks (MANETs). It begins by introducing MANETs and explaining that they are temporary networks formed spontaneously via wireless communication between mobile nodes without centralized administration. It then discusses the need for mobility management, including location management and handoff management routing protocols. It also discusses different types of node mobility and mobility models for predicting node movement patterns over time in MANETs. The document categorizes mobility models as trace-based (using real movement data) or synthetic-based (simulating realistic movement), and lists examples of models within each category like the random waypoint and reference point group mobility models.
How to put these nodes together to form a meaningful network.
How a network should function at high-level application scenarios .
On the basis of these scenarios and optimization goals, the design of networking protocols in wireless sensor networks are derived
A proper service interface is required and integration of WSNs into larger network contexts.
Global State Routing (GSR) maintains a global knowledge of network topology like link state routing but avoids inefficient flooding. Each node periodically exchanges its link state table only with neighbors, not the entire network. This reduces overhead compared to link state routing. GSR nodes use Dijkstra's algorithm on the accumulated link state information to compute optimal paths locally without global flooding.
This document discusses the origins and development of ad hoc networks. It describes how packet radio networks (PRNETs) in the 1970s, developed by DARPA, were the first generation of ad hoc networks. PRNETs used multi-hop routing between mobile radio terminals and packet radios to communicate without fixed infrastructure. The document outlines the key components and routing techniques of PRNETs, including point-to-point and broadcast routing. It also discusses how subsequent generations in the 1980s-1990s focused on improving performance, scalability, and developing commercial applications like Bluetooth.
Lecture 7 8 ad hoc wireless media access protocolsChandra Meena
1) The document discusses issues with media access control (MAC) protocols in ad hoc wireless networks, including problems like hidden terminals and exposed nodes.
2) It classifies MAC protocols as synchronous, asynchronous, receiver-initiated, or sender-initiated. The RTS-CTS handshake is presented as a solution to the hidden terminal problem.
3) However, the RTS-CTS approach has shortcomings like collisions when RTS and CTS messages are sent by different nodes or when multiple CTS messages are granted. Solutions to the exposed node problem are also discussed.
Mobile ad-hoc networks have frequent host and topology changes with no cellular infrastructure and require multi-hop wireless links for data transmission between nodes. Routing protocols must discover routes between nodes that may not be directly connected. Table-driven protocols like Destination Sequenced Distance Vector (DSDV) and Wireless Routing Protocol (WRP) maintain up-to-date routing tables through periodic broadcasts but generate significant control overhead. DSDV uses sequence numbers to distinguish stale routes and avoid loops while WRP maintains four tables for routing information.
1. Reinforcement learning involves an agent learning through trial-and-error interactions with an environment. The agent learns a policy for how to act by maximizing rewards.
2. The document outlines key elements of reinforcement learning including states, actions, rewards, value functions, and explores different methods for solving reinforcement learning problems including dynamic programming, Monte Carlo methods, and temporal difference learning.
3. Temporal difference learning combines the advantages of Monte Carlo methods and dynamic programming by allowing for incremental learning through bootstrapping predictions like dynamic programming while also learning directly from experience like Monte Carlo methods.
Lecture 2 evolution of mobile cellular Chandra Meena
This document provides an overview of mobile and ad hoc networks. It discusses the evolution of cellular networks from early radio communication systems through modern generations like 5G. Key topics covered include the fundamentals of wireless technologies, radio propagation mechanisms, characteristics of the wireless channel, and cellular network components and terminology. Generations of cellular standards are defined, including 1G analog networks like AMPS, 2G digital networks like GSM that enabled data services, and subsequent generations with improved capabilities.
Lecture 1 mobile and adhoc network- introductionChandra Meena
This document provides an overview of a course on mobile and ad hoc networks. It lists two textbooks that will be used and states that the goal is to cover fundamental design issues and solutions for network architecture and protocols. It also lists some related websites and outlines the objectives of chapters that will introduce wireless communication technologies, network standards, and multiple access techniques for ad hoc networks.
Lecture 23 27. quality of services in ad hoc wireless networksChandra Meena
The document discusses quality of service (QoS) in mobile ad hoc networks (MANETs). It covers several key topics:
1) The challenges of providing QoS in MANETs due to their dynamic and decentralized nature.
2) Different approaches to QoS classification and provisioning at various network layers. This includes MAC layer solutions like IEEE 802.11e and network layer solutions like QoS-aware routing protocols.
3) Specific QoS routing protocols discussed, including ticket-based, predictive location-based, and trigger-based distributed protocols.
The document discusses ad hoc networks and wireless sensor networks. It defines an ad hoc network as a temporary network composed of mobile nodes without preexisting infrastructure that is self-organizing. Wireless sensor networks are introduced as a collection of sensor nodes densely deployed to monitor conditions and cooperatively pass data back to central nodes. The document outlines key characteristics of both networks including their temporary and adaptive nature, multi-hop routing, and challenges of mobility, power constraints, and dynamic topology changes.
AODV and DSR are two routing protocols evaluated. AODV uses an on-demand approach where route requests are broadcast to discover paths between source and destination. Intermediate nodes record reverse paths for routing replies. When a link fails, a notification is sent to update routes. DSR stores source routes in packet headers. Route discovery broadcasts requests to build source routes, and route maintenance uses route error packets to update routes when failures occur. The performance of these protocols was analyzed using a simulation tool.
- Mobile ad hoc networks (MANETs) are autonomous systems of wireless nodes that can dynamically change topology as nodes move. Routing must adapt to these changes.
- There are two main categories of routing protocols: table-driven protocols proactively maintain consistent, up-to-date routing tables whereas on-demand protocols only determine routes when needed.
- Examples of protocols include DSDV as a table-driven protocol and AODV as an on-demand protocol, with AODV using route requests and replies to discover routes only when transmitting data.
Secured Preemptive DSR(S-PDSR): An integration of SRP and SMT with Preemptive...ijasuc
In Contrast with traditional networks, ad hoc networks not require any previously built
infrastructure, they are distributed and fully self-organized systems. Due to absence of any
fixed node, each node acts as a router, providing routing capabilities of the MANET. In a
distributed network, with out any infrastructure communicating peers have to rely on the
whole network, therefore the proper security hardly can be established. This paper proposes
enhancements in Preemptive DSR to provide secured route discovery. This paper evaluates
integration of Secured Routing Protocol (SRP) and Secured Message Transmission(SMT) with
Preemptive Dynamic Source Routing (PDSR) to get Secured PDSR(S-PDSR), which is
capable of secured route discovery.
Secured Preemptive DSR(S-PDSR): An integration of SRP and SMT with Preemptive...ijasuc
This document proposes enhancements to Preemptive DSR (PDSR) called Secured Preemptive DSR (S-PDSR) to provide secured route discovery in mobile ad hoc networks. S-PDSR integrates the Secured Routing Protocol (SRP) and Secured Message Transmission (SMT) with PDSR. PDSR is an on-demand routing protocol that discovers multiple routes to allow for secured data transmission. The proposed S-PDSR protocol exploits this feature of PDSR to incorporate SRP for secured route discovery and allow SMT to use the multiple routes to ensure secure data transmission in the network.
Secured Preemptive DSR(S-PDSR): An integration of SRP and SMT with Preemptive...ijasuc
This document proposes enhancements to Preemptive DSR (PDSR) called Secured Preemptive DSR (S-PDSR) to provide secured route discovery in mobile ad hoc networks. S-PDSR integrates the Secured Routing Protocol (SRP) and Secured Message Transmission (SMT) with PDSR. PDSR is an on-demand routing protocol that discovers multiple routes to allow for secured data transmission. The proposed S-PDSR protocol exploits this feature of PDSR to incorporate SRP for secured route discovery and allow SMT to use the multiple routes to ensure secure data transmission.
This document provides an overview of the Dynamic Source Routing (DSR) protocol for mobile ad hoc networks. DSR is a reactive, on-demand routing protocol that uses route discovery and route maintenance through flooding of route request and route reply packets. Key aspects covered include: how DSR performs route discovery by broadcasting route requests; how the destination responds with a route reply listing the full end-to-end path; how nodes cache routes for potential future use; and how route errors trigger new route discovery if needed. DSR optimization through aggressive route caching is also discussed to speed up routing.
Ad hoc network-performance_analysis and simulationAyush Chhangani
This document presents a comparative study and simulation of three ad-hoc routing protocols: AODV, DSR, and DSDV. It describes the algorithms, operation, and code used to simulate the routing protocols in NS2. The document defines the routing protocols, illustrates their operations with examples, and includes the NS2 code used to simulate and compare the performance of the protocols in a mobile ad-hoc network scenario.
This document summarizes several routing protocols for ad hoc wireless networks. It describes the challenges in this domain including dynamic topologies and limited resources. It then categorizes and explains several types of routing protocols, including proactive protocols like DSDV, reactive protocols like AODV and DSR, hybrid protocols like ZRP, and geographic routing. It provides details on the route discovery and maintenance mechanisms of some of these prominent protocols. It also discusses theoretical limits on network capacity and the impact of mobility and hierarchy.
Simulation & comparison of aodv & dsr protocolPrafull Johri
This document summarizes and compares two reactive routing protocols - AODV and DSR. It discusses how NS2 was extended to simulate wireless networks and the two protocols. AODV uses route discovery to find paths, maintains route tables, and can locally repair broken links. DSR also uses route discovery but source routes are carried in packet headers. While AODV has lower initial packet loss, DSR performance improves over time, so either protocol can be used for longer simulations.
This document discusses MANET routing protocols and compares AODV and DSR protocols. It provides an overview of ad hoc networks and their key characteristics like being decentralized and relying on participating nodes to forward data. It then describes the main categories of ad hoc routing protocols - proactive (table-driven) and reactive (on-demand). The document dives deeper into AODV and DSR protocols, explaining their path discovery, maintenance and other mechanisms. The key differences noted are that DSR can handle uni-directional and bi-directional links while both protocols employ on-demand routing and broadcast discovery but use different approaches for route information storage and link failure handling.
Default and On demand routing - Advance Computer NetworksSonali Parab
Routing is the process of selecting best paths in a network. In the past, the term routing was also used to mean forwarding network traffic among networks. However this latter function is much better described as simply forwarding. Routing is performed for many kinds of networks, including the telephone network (circuit switching), electronic data networks (such as the Internet), and transportation networks.
In packet switching networks, routing directs packet forwarding (the transit of logically addressed network packets from their source toward their ultimate destination) through intermediate nodes. Intermediate nodes are typically network hardware devices such as routers, bridges, gateways, firewalls, or switches. General-purpose computers can also forward packets and perform routing, though they are not specialized hardware and may suffer from limited performance. The routing process usually directs forwarding on the basis of routing tables which maintain a record of the routes to various network destinations. Thus, constructing routing tables, which are held in the router's memory, is very important for efficient routing. Most routing algorithms use only one network path at a time. Multipath routing techniques enable the use of multiple alternative paths.
The document summarizes several routing protocols used in wireless networks. It discusses both table-driven protocols like DSDV and on-demand protocols like AODV. It provides details on how each protocol performs routing and maintains routes. It also outlines some advantages and disadvantages of protocols like DSDV, AODV, DSR, and TORA.
The document discusses designing energy efficient routing protocols for mobile ad hoc networks (MANETs). It outlines several key points:
- MANETs are infrastructureless wireless networks formed by mobile nodes without centralized administration. Routing in MANETs is challenging due to the dynamic topology.
- Several routing protocols for MANETs are studied, including AODV, DSR and protocols that optimize power consumption like EPAR.
- The performance of these protocols is evaluated using MATLAB simulations based on metrics like packet delivery ratio, delay and throughput. The goal is to design a protocol that maximizes network lifetime by choosing routes with minimum total transmission power while ensuring nodes have sufficient battery capacity.
Performance Comparison and Analysis of Preemptive-DSR and TORA ijasuc
The Dynamic Source Routing protocol (DSR) is a simple and efficient routing protocol designed
specifically for use in multi-hop wireless ad hoc networks of mobile nodes. Preemptive DSR(PDSR) is the
modified version of DSR. The main objective of this paper is to analyze and compare the performance of
Preemptive DSR and Temporarily Ordered Routing Algorithm(TORA).It discusses the effect of variation in
number of nodes and average speed on protocol performance. Simulation results (provided by the
instructor) are analyzed to get an insight into the operation of TORA and PDSR in small/large sized
networks with slow/fast moving nodes. Results show that PDSR outperforms TORA in terms of the number
of MANET control packets used to maintain/erase routes. Also, it is concluded that TORA is a better choice
than PDSR for fast moving highly connected set of nodes. It is also observed that DSR provides better data
throughput than TORA and that routes can be created faster in PDSR than in TORA. This paper tries to
explain the reasons behind the nature of the results.
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This document summarizes several multipath routing protocols for mobile ad hoc networks (MANETs). It discusses Ad Hoc On-Demand Distance Vector (AODV) routing, which uses on-demand route discovery and maintenance. It also describes Ad hoc On-Demand Multipath Distance Vector (AOMDV) routing, which extends AODV to find multiple disjoint paths. Additionally, it reviews a Load Balancing Multipath AODV (LB-M AODV) protocol that uses multiple paths to increase delivery ratio and balances load. Finally, it briefly discusses a Backup Path Routing protocol that selects primary and backup paths, and a Prioritized Routing (PRIMAR) protocol that considers packet priority when
Research Inventy : International Journal of Engineering and Scienceresearchinventy
Research Inventy : International Journal of Engineering and Science is published by the group of young academic and industrial researchers with 12 Issues per year. It is an online as well as print version open access journal that provides rapid publication (monthly) of articles in all areas of the subject such as: civil, mechanical, chemical, electronic and computer engineering as well as production and information technology. The Journal welcomes the submission of manuscripts that meet the general criteria of significance and scientific excellence. Papers will be published by rapid process within 20 days after acceptance and peer review process takes only 7 days. All articles published in Research Inventy will be peer-reviewed.
Caching strategies for on demand routing protocols for wireless ad hoc networkAcel-Omeran
This document analyzes caching strategies for on-demand routing protocols in wireless ad hoc networks. It evaluates different design choices for cache structure, capacity, and timeout using the Dynamic Source Routing (DSR) protocol through detailed simulations. The simulations consider 50 different mobility scenarios drawn from 5 mobility models to analyze how caching algorithms are affected by node movement patterns.
The document discusses routing protocols for mobile ad hoc networks (MANETs). It begins by defining MANETs and their unique characteristics, such as moving nodes, wireless links, and power constraints. Some key challenges for MANET routing protocols are the need for dynamic routing due to frequent topology changes and minimizing routing overhead. The document then discusses various categories of MANET routing protocols, including reactive protocols like DSR and AODV, proactive protocols, and hybrid and location-based protocols. It provides more detailed explanations of the route discovery and maintenance processes for DSR and AODV.
Link-and Node-Disjoint Evaluation of the Ad Hoc on Demand Multi-path Distance...Eswar Publications
This work illustrates the AOMDV routing protocol. Its ancestor, the AODV routing protocol is also described. This tutorial demonstrates how forward and reverse paths are created by the AOMDV routing protocol. Loop free paths formulation is described, together with node and link disjoint paths. Finally, the performance of the AOMDV routing protocol is investigated along link and node disjoint paths. The WSN with the AOMDV routing protocol using link disjoint paths is better than the WSN with the AOMDV routing protocol using node disjoint paths for energy consumption.
Similar to Lecture 11 14. Adhoc routing protocols cont.. (20)
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4. 4
Table-driven vs. On-demand
Table-Driven Routing Protocol:
proactive
continuously evaluate the routes
attempt to maintain consistent, up-to-date routing information
when a route is needed, one may be ready immediately
when the network topology changes
the protocol responds by propagating updates throughout the network to
maintain a consistent view
5. 5
Table-driven vs. On-demand (cont.)
Source-Initiated On-Demand Routing Protocol:
Reactive
on-demand style: create routes only when it is desired by the source
node
route discovery: invoke a route-determination procedure, the procedure is
terminated when
a route has been found
no route is found after all route permutations are examined
route maintained by a route maintenance procedure until
inaccessible along every path from the source
no longer desired
longer delay: sometimes a route may not be ready for use
immediately when data packets come
6. On-Demand Driven/ Reactive
protocols
In a reactive protocol, a route is discovered only when it is
necessary.
In other words, the protocol tries to discover a route only on-
demand, when it is necessary.
These protocols generate much less control traffic at the cost of
latency, but it usually takes more time to find a route
compared to a proactive protocol.
6
7. Source-Initiated On-Demand
Approaches
Creates routes only when desired by the source node.
finds a route on demand by flooding the network with Route
Request packets.
When a node requires a route to a destination, it initiates a route
discovery process within the network.
Completed when either a route is found or all possible route
permutations have been examined.
Once a route has been discovered and established, it is maintained
by some form of route maintenance procedure until either the
destination becomes inaccessible along every path from the source
or the route is no longer desired.
7
8. 8
Source-initiated on-demand
1. Dynamic Source Routing (DSR)
D. B. Johnson and D.A. Maltz,“Dynamic Source Routing inAd-HocWireless Networks,”
Mobile Computing,T. Imielinski and H. Korth, Eds., Kluwer, 1996, pp. 153–81.
2. Ad-Hoc on-demand distance vector routing (AODV)
C. E. Perkins and E. M. Royer,“Ad-hoc On-Demand DistanceVector Routing,” Proc. 2nd
IEEEWksp. Mobile Comp. Sys. andApps., Feb. 1999, pp. 90–100.
3. Temporally ordered routing algorithm (TORA)
V. D. Park and M. S. Corson,“A HighlyAdaptive Distributed RoutingAlgorithm for
MobileWireless Networks,” Proc. INFOCOM ’97,Apr. 1997.
4. Associativity-Based routing (ABR)
C-K.Toh,“A Novel Distributed Routing ProtocolTo SupportAd-Hoc Mobile Computing,”
Proc. 1996 IEEE 15thAnnual Int’l. Phoenix Conf. Comp. and Commun., Mar. 1996, pp.
480–86.
5. Signal stability routing (SSR)
R. Dube et al.,“Signal Stability basedAdaptive Routing (SSA) forAd-Hoc Mobile
Networks,” IEEE Pers. Commun., Feb. 1997, pp. 36–45.
9. 1. Dynamic Source Routing (DSR)
D. B. Johnson and D.A. Maltz,“Dynamic Source Routing inAd-HocWireless Networks,”
Mobile Computing,T. Imielinski and H. Korth, Eds., Kluwer, 1996, pp. 153–81.
On-demand routing protocol
based on the concept of source routing
Designed to restrict the bandwidth consumed by control packets in table
driven approach
Eliminated the periodic table-update message (hello packet/
beacon)
9
10. Dynamic Source Routing (DSR)
Each host maintains a route cache which contains all routes it
has learnt.
Source Routing:
routes are denoted with complete information (each hop is
registered)
Two major parts:
route discovery
route maintenance
10
11. Dynamic Source Routing (DSR)
When a host has a packet to send, it first consults its route cache.
If there is an unexpired route, then it will use it.
Otherwise, a route discovery will be performed
Route Discovery:
Initiates by broadcasting a route request packet.
Source node S floods Route Request (RREQ)
Route request message contains
Address of the destination,
Source node's address and
Unique identification number.
Each node appends own identifier(Sequence number) when forwarding RREQ Entries in the
route cache are continually updated as new routes are learned.
11
12. Dynamic Source Routing (DSR)
There is a “route record” field in the packet.
The source node will add its address to the record.
On receipt of the packet, a host will add its address to the “route
record” and rebroadcast the packet.
Each node receiving the packet checks whether it knows of a route to the
destination.
If it does not, it adds its own address to the route record of the packet and then
forwards the packet along its outgoing links.
To limit the number of ROUTE_REQUEST packets:
Each node only rebroadcasts the packet at most once.
Each node will consult its route cache to see if a route is already
known.
12
13. Route Discovery in DSR
13
B
A
S E
F
H
J
D
C
G
I
K
Z
Y
Represents a node that has received RREQ for D from S
M
N
L
14. Route Discovery in DSR
B
A
S E
F
H
J
D
C
G
I
K
Represents transmission of RREQ
Z
Y
Broadcast transmission
M
N
L
[S]
[X,Y] Represents list of identifiers appended to RREQ14
15. Route Discovery in DSR
B
A
S E
F
H
J
D
C
G
I
K
• Node H receives packet RREQ from two neighbors:
potential for collision
Z
Y
M
N
L
[S,E]
[S,C]
15
16. Route Discovery in DSR
B
A
S E
F
H
J
D
C
G
I
K
• Node C receives RREQ from G and H, but does not forward it again,
because node C has already forwarded RREQ once
Z
Y
M
N
L
[S,C,G]
[S,E,F]
16
17. Route Discovery in DSR
17
B
A
S E
F
H
J
D
C
G
I
K
Z
Y
M
• Nodes J and K both broadcast RREQ to node D
• Since nodes J and K are hidden from each other, their transmissions
may collide
N
L
[S,C,G,K]
[S,E,F,J]
18. Route Discovery in DSR
18
B
A
S E
F
H
J
D
C
G
I
K
Z
Y
• Node D does not forward RREQ, because node D
is the intended target of the route discovery
M
N
L
[S,E,F,J,M]
19. Route Discovery in DSR
A ROUTE_REPLY packet is generated when
the route request packet reaches the destination
an intermediate host has an unexpired route to the destination
Destination D on receiving the first RREQ, sends a Route
Reply (RREP)
RREP is sent on a route obtained by reversing the route
appended to received RREQ
RREP includes the route from S to D on which RREQ was
received by node D
19
20. Route Reply in DSR
20
B
A
S E
F
H
J
D
C
G
I
K
Z
Y
M
N
L
RREP [S,E,F,J,D]
Represents RREP control message
21. Dynamic Source Routing
The ROUTE_REPLY packet will contain a route generated in
following manner:
Use the route of destination route cache (if route cache has the route
information)
the route that was traversed by the ROUTE_REQUEST packet (if
symmetric)
route discovery and piggyback the route reply on the new request (if
asymmetric)
Node S on receiving RREP, caches the route included in the RREP
Source routing
When node S sends a data packet to D, the entire route is included in
the packet header
Intermediate nodes use the source route included in a packet to
determine to whom a packet should be forwarded21
22. Data Delivery in DSR
22
B
A
S E
F
H
J
D
C
G
I
K
Z
Y
M
N
L
DATA [S,E,F,J,D]
Packet header size grows with route length
24. 24
Dynamic Source Routing (DSR)
Routing maintenance
Use acknowledgements or a layer-2 scheme to detect broken links.
Inform sender via route error packet.
Initiate route discovery.
All routes which contain the breakage hop have to be removed from
the route cache.
Route Error packet
26. DSR Overview
Advantages
Designed to restrict the bandwidth consumed by control packets in table driven approach
Eliminated the periodic table-update message (hello packet/ beacon)
Routes maintained only between nodes who need to communicate (on demand )thus
reduces overhead of route maintenance
Route caching can further reduce route discovery overhead
A single route discovery may yield many routes to the destination, due to intermediate nodes
replying from local caches
Disadvantage
Packet header size grows with route length due to source routing degrade
performance- when data contents of a packet are small
Flood of route requests may potentially reach all nodes in the network
Potential collisions between route requests propagated by neighboring nodes
Increased contention if too many route replies come back due to nodes replying using their
local cache
Route Reply Storm problem
26
27. 2. Ad Hoc On-Demand Distance Vector
Routing Protocol (AODV)
C. E. Perkins and E. M. Royer,“Ad-hoc On-Demand DistanceVector Routing,” Proc. 2nd IEEE
Wksp. Mobile Comp. Sys. andApps., Feb. 1999, pp. 90–100.
DSR includes source routes in packet headers, resulting large headers.
AODV attempts to improve on DSR
by maintaining routing tables at the nodes, so that data packets do not have to contain
routes,
InAODV, the source node and the intermediate nodes store the next hop information
corresponding to each flow data packet transmission.
AODV relies on dynamically establishing route table entries at intermediate node.
AODV retains the desirable feature of DSR that routes are maintained only between
nodes which need to communicate
27
28. Ad Hoc On-Demand Distance
Vector Routing Protocol
AODV is an improvement on DSDV
minimizes the number of required broadcasts
by creating routes on an on-demand basis
AODV use the concept of destination sequence number from DSDV to determine an
up-to-date path to the destination.
It is a pure on-demand route acquisition system
AODV only supports the use of symmetric links.
Nodes which are not on a selected path do not maintain routing information or
participate in routing table exchanges.
28
29. 29
AODV
Includes
Route discovery
Route maintenance.
Path discovery procedure using RREQ/RREP query cycles.
Reverse Path setup
Forward path setup
Route table management
AODV maintains routes as long as they are active.
Path maintenance
The source moves: reinitiate the route discovery
Other node moves: a special RREP is sent to the affected source nodes
Local connectivity management
Broadcasts used to update local connectivity information
Inactive nodes in an active path required to send “hello” messages
30. Route Requests in AODV
30
B
A
S E
F
H
J
D
C
G
I
K
Z
Y
Represents a node that has received RREQ for D from S
M
N
L
31. AODV
Route Requests (RREQ) are forwarded in a manner similar to DSR
Route request message contains
Source identifier (SrcID)
Destination identifier (DestID)
Source sequence number (SrcSeqNum)
Destination sequence number (DestSeqNum)
Broadcast identifier (BcastID) andTime to live(TTL) field
When a node re-broadcasts a Route Request, it sets up a reverse path pointing
towards the source
AODV assumes symmetric (bi-directional) links
When the intended destination receives a Route Request, it replies by sending
a Route Reply (RREP)
Route Reply travels along the reverse path set-up when Route Request is
forwarded31
32. Route Requests in AODV
32
B
A
S E
F
H
J
D
C
G
I
K
Represents transmission of RREQ
Z
Y
Broadcast transmission
M
N
L
33. Route Requests in AODV
33
B
A
S E
F
H
J
D
C
G
I
K
Represents links on Reverse Path
Z
Y
M
N
L
34. Reverse Path Setup in AODV
34
B
A
S E
F
H
J
D
C
G
I
K
• Node C receives RREQ from G and H, but does not forward
it again, because node C has already forwarded RREQ once
Z
Y
M
N
L
36. Reverse Path Setup in AODV
36
B
A
S E
F
H
J
D
C
G
I
K
Z
Y
• Node D does not forward RREQ, because node D
is the intended target of the RREQ
M
N
L
37. Forward Path Setup in AODV
37
B
A
S E
F
H
J
D
C
G
I
K
Z
Y
M
N
L
Forward links are setup when RREP travels along
the reverse path
Represents a link on the forward path
38. Ad Hoc On-Demand Distance Vector Routing
(AODV)
AODV uses destination sequence numbers to ensure that all routes are
loop-free and contain the most recent route information.
Each node maintains its own sequence number, as well as a broadcast ID.
The broadcast ID is incremented for every RREQ the node initiates, and
together with the node's IP address, uniquely identifies an RREQ.
Source node includes in the RREQ the most recent sequence number it
has for the destination.
Intermediate nodes can reply to the RREQ only if they have a route to
the destination whose corresponding destination sequence number is
greater than or equal to that contained in the RREQ.
38
39. Ad Hoc On-Demand Distance Vector Routing
(AODV)
At the time of forwarding the RREQ, intermediate nodes record the
address of neighbors from which the first copy of broadcast packet
was received, in their route tables, to establishing a reverse path.
Once the RREQ has reached the destination,
It responds by unicasting a route reply (RREP) packet back to the neighbor from
which it first received the RREQ and so on.
As the RREP is routed back along the reverse path, nodes along this path set up
forward route entries in their route tables that point to the node from which
the RREP came.
A route timer is associated with each route entry, which causes the deletion of
the entry if it is not used within a specified lifetime.
Because an RREP is forwarded along the path established by an RREQ, AODV
only supports the use of symmetric links.
39
40. Route Request and Route Reply
Route Request (RREQ) includes the last known sequence number for
the destination
An intermediate node may also send a Route Reply (RREP)
provided that it knows a more recent path than the one
previously known to sender
Intermediate nodes that forward the RREP, also record the next hop to
destination
A routing table entry maintaining a reverse path is purged after a
timeout interval
A routing table entry maintaining a forward path is purged if not used for
a active_route_timeout interval
40
41. Ad Hoc On-Demand Distance Vector Routing
(AODV)
Consideration for other better routes is absent in AODV.
This approached was first proposed in Associativity Based Routing (ABR) in 1994 and
protected by the ABR US patent.
In AODV, routes are maintained as follows:
If a source node moves, it reinitiate the route discovery protocol to find a new route.
If a node along the route moves, its upstream neighbor notices the move and
propagates a link failure notification message (an RREP with an infinite metric) to
each of its active upstream neighbors to inform them of the erasure of that part of the
route.
These nodes in turn propagate the link failure notification to their upstream
neighbors, and so on, until the source node is reached.
The source node may then choose to re-initiate route discovery for that destination if
a route is still desired.41
42. AODV: Summary
Advantages
The authors claim scalability up to 10,000 nodes (performance suffers, simulation
results)
Routes are established on demand
Routes need not be included in packet headers
Nodes maintain routing tables containing entries only for routes that are in active use
Destination sequence no are used to find the latest route to the destination
Sequence numbers are used to avoid old/broken routes and formation of routing loops
Connection setup is less
Disadvantage
Intermediate nodes can lead to inconsistent routes if the source
sequence no is very old and the intermediate node have a higher but
not the latest destination sequenced no.
Periodic beaconing leads to unnecessary bandwidth consumption.
42
43. 3. Temporally Ordered Routing
Algorithm (TORA)
V. D. Park and M. S. Corson,“A HighlyAdaptive Distributed RoutingAlgorithm for Mobile
Wireless Networks,” Proc. INFOCOM ’97,Apr. 1997.
TORA is proposed to operate in a highly dynamic mobile networking
environment.
Highly adaptive, loop-free, distributed routing algorithm based on the
concept of link reversal.
Key design concept ofTORA
localization of control messages to a very small set of nodes near the occurrence of a
topological change.
To accomplish this, nodes need to maintain routing information about adjacent (one-
hop) nodes.
The height metric is used to model the routing state of the network.
The protocol performs three basic functions:
(a) route creation, (b) route maintenance, and (c) route erasure.
43
44. 44
TORA: Temporally ordered routing
During the route creation and maintenance phase, nodes establish a
directed acyclic graph(DAG).
A logical direction is imposed on the links towards the destination
Source-initiated and provides multiple routes for any desired
source/destination pair.
Starting from any node in the graph, a destination can be reached by
following the directed links
Highly adaptive, efficient, scalable, distributed algorithm
Multiple routes from source to destination
For highly dynamic mobile, multi-hop wireless network
A
C
E
D
F
G
B
45. 45
TORA
Assigns a reference level (height) to each node
A DAG is maintained for each destination
Synchronized clock is important, accomplished via GPS or
algorithm such as NetworkTime Protocol.
Timing is an important factor forTORA because the “height” metric is
dependent on the logical time of a link failure.
metric:
logical time of a link failure
The unique ID of the node that defined the new reference level
A reflection indicator bit
A propagation ordering parameter
The unique ID of the node
Adjust reference level to restore routes on link failure
Query,Update,Clear packets used for creating, maintaining and
erasing routes
46. 46
TORA
Three major tasks
Route creation: QRY and UPD packets
Route maintenance
Route erasure: Clear packet (CLR) is broadcasted
Using Unique node ID and unique reference ID
Route Creation: demand driven “query/reply”
Performed only when a node requires a path to a destination but does not have nay
directed link.
A query packet (QRY) is flooded through network
An update packet (UPD) propagates back if routes exist
Route Maintenance: “link-reversal” algorithm
React only when necessary
Reaction to link failure is localized in scope
Route Erasure:
A clear packet (CLR) is flooded through network to erase invalid routes
47. 47
TORA
Route creation of TORA
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
s s
d d
Propogation of QRY
(reference level, height)
Height of each node
updated by UPD
Route Creation in TORA
(-,-)
(-,-)
(-,-)
(-,-)
(-,-)
(-,-)
(0,0)
(-,-)
(0,3) (0,3)
(0,3)
(0,2)
(0,1)
(0,0)
(0,1)(0,2)
48. 48
TORA
Creation of route
C
A B
E
G (DEST)
F
H
D
QRY
QRY
QRY
UPD
QRY
QRY
UPD
UPD
UP
D
UPD UPD
UPD
49. a
f
e
d
c
b
h
g
(-,-,-,-,d)
(-,-,-,-,b)
(-,-,-,-,c)
(-,-,-,-,f)(-,,-,-,-e)
Only the non-NULL node (destination) responds with a UPD packet.
(0,0,0,0,h)
(-,-,-,-,a)
The source broadcasts a QRY packet with height(D)=0, all others NULL
(0,0,0,4,b)
(0,0,0,4,c)
(0,0,0,3,e)
(0,0,0,2,f)
(0,0,0,2,d)
(0,0,0,3,a)
source
Dest.
A node receiving a UPD sets its height to one more than UPD
Source receives a UPD with less height
UPD
QRY
QRYQRY
(-,-,-,-,g)(0,0,0,1,g)
49
QRY
QRY
QRY
QRY
QRY
QRY
52. TORA: Summary
Advantages
Less control overload: by limiting the control packets for route reconfiguration
to a small region
Disadvantage
The local reconfiguration of paths results in non-optimal routes
Concurrent deduction of partitions and subsequent deletion of routes could result
in temporary oscillations and transient loops.
52
53. 4. ABR: Associativity-Based routing
C-K.Toh,“A Novel Distributed Routing ProtocolTo SupportAd-Hoc Mobile Computing,” Proc. 1996
IEEE 15thAnnual Int’l. Phoenix Conf. Comp. and Commun., Mar. 1996, pp. 480–86.
First routing protocol that advocates the selection of stable links and routes for
ad hoc wireless networks.
Goal: Best route is selected based on stability and shortest path of wireless
link .
Associativity is related to the spatial, temporal, and connection stability of a mobile host
(MH).
The stability is measured using associativity ticks(initially set to zero)
Each node broadcasts beacons, the nodes increment associativity ticks when they receive
beacons and sets zero if beacon is not received. High Associativity means high
stability.
A node's association with its neighbors changes as it is migrating, and its transition period
can be identified by associativity ticks or counts.
53
54. Associativity-Based routing
Selects route based on the stability for the wireless links.
Beacon-based, on demand routing protocol
Link is classified as stable or unstable based on its temporal stability
Temporal stability is determined by counting the periodic beacons that a node
receive from its neighbors.
Each node maintains the count of its neighbors’ beacons and on the basis of
beacon count corresponding to the neighbor node concerned. classifies each
link as
stable link : link corresponding to a stable neighbor
unstable : link to an unstable neighbor
A source node floods RouteRequest packets in the network if a route is not
available in its route cache.
All intermediate node forward the RouteRequest packets.
54
55. Associativity-Based routing
RouteRequest packet carries the path it has traversed and the beacon
count for the corresponding nodes in the path.
When the first RouteRequest reaches the destination , the destination waits for
a period TrouteselceteTime to receive multiple RouteRequest through different
paths.
After this time , destination selects the path that has the max. no of
stable links.
If two paths have same proportion of stable links, shortest path is selected.
If more than one shortest path available, random path is selected.
ABR doesn't restrict any intermediate node from forwarding a RouteRequest
packet based on the stable or unstable link criterion.
It uses stability information only during the route selection process at the
destination node.
ABR give more priority to stable routes than to shorter routes.
55
56. 56
Associativity-Based routing
Source Initiated Routing, Query-Reply packets
Route is long-lived and free from loops, deadlock, and packet duplicates
ABR provides the method of reconstructing when link fails
The protocol contains 3 phases:
Route discovery: BQ-REPLY cycle
Route reconstruction (RRC):
Route deletion (RD): Source-initiated
57. 57
ABR
Route discovery: accomplished by a broadcast query and await-reply(BQ-
REPLY) cycle.
A node desiring a route broadcasts a BQ message . In search of mobiles a route broadcasts a
BQ(Broadcast query) message in search of mobiles that have a route to the destination
All nodes receiving the BQ append their address and their associativity ticks with their
neighbors along with QoS information to query packet.
A successor node erases its upstream node neighbor’s associativity ticks entries and retains
only the entry concerned with itself and its upstream node.
The destination computes the total of the associativity ticks
The destination will know all the possible routes and their qualities. It then selects the
best route based on stability and associativity ticks.
If multiple paths have the same overall degree of association stability, the route with
minimum number of hops is selected.
58. Temporal and spatial representation of associativity of a
mobile node with its neighbors.
58
59. Rule and Property of Associativity
59
Scenario:
cell size d = 10m
MH min migration speed v = 2m/s
Beacon transmission interval p = 1s
Athreshold = 2 r /(vp) = 5
Association stability results when no. of beacons recorded is >
Athreshold
Low associativity ticks high state of mobility
High associativity ticks stable state
Stability is also determined by signal strength and power life.
60. ABR
Stability in ABR refers to more than just associativity ticks. It also
includes
signal strength:defines the quality of the signal propagation channel
power life:describes the current power life of the device
Advances in radio transceiver technology has enabled one to monitor
signal strength over time and store this information into memory.
Advances in smart battery technology has enabled us to monitor
remaining power life of battery-powered devices.
Such information, can be used to govern route stability.
60
61. ABR: Summary
Advantages
Stable routes have a higher preference compared to shorter routes.
Fewer path breaks
Reduce the extent of flooding due to reconfiguration of paths in the
network.
Disadvantage
Chosen Path maybe longer than the shortest path between the source and
destination because of the preference given to stable paths.
Local query (LQ) broadcast may result in high delays during route repairs .
61
62. 62
5. Signal Stability Routing (SSR)
Advance form of ABR
New metric: signal strength between nodes and a node’s location
stability
Selects routes based on signal strength between nodes Prefers stronger
connectivity.
Tables
Signal Strength Table (SST)–
Periodic beacons from the link layer of the neighbouring nodes:
fields [host, signal strength, last, clicks, set]
Signal strength recorded by SST-- Weak or Strong
Routing Table (RT)
field [destination, next host].
Two protocols
Dynamic Routing Protocol (DRP): manages SST & RT
Static Routing Protocol (SRP): forwards packets based on RT
64. Signal Stability Routing (SSR)
SSR consists of 2 cooperative protocols:
Dynamic Routing (DRP)
Maintain signal stability table(SST) with and routing table(RT)
After updating all appropriate table entries, the DRP passes a received packet to
the SRP
Static Routing (SRP) :
Passing the packet up the stack if it is the intended receiver
If no entry is found in the RT for the destination, initiate a route-search
process to find a route
Else forwarding the packet
Send a route reply message back to initiator
All transmission are received and processed by DRP
After processing and updating the table DRP passes the packets to SRP
64
65. 65
SSR (cont.)
Route discovery and route maintenance
By default, only route request packets from strong channels are forwarded
initiate a new route-search process; erase the old route
If there is no route-reply message received, the route changes to accept
weak channel.
A
B
C
D
E
F A
B
C
D
E
F
66. SSR ( route search)
Passes the packets to the stack or look for destination in RT
If no entry is in RT for destination a new route search process is initiated.
Weak channels are accepted only if timed out occur for receiving a route
reply message.
In case of link failure intermediate nodes send error message to the source
indicating the broken channel and a new route search process is initialized
Assumptions:
Route search packets arrives at destination along the strongest signal
capability
66
68. SSR: Summary
Advantages
To select strong connection leads to fewer route reconstruction
More stable route as compared to shortest path route selection
protocols such as AODV and DSR.
Disadvantage
Long delay since intermediate nodes can’t answer the path (unlikeAODV, DSR)
68
70. Exploits location information to limit scope of flooding for route request
Limit the search for a new route to a smaller request zone.
Reduce the signalling traffic
Location information may be obtained using GPS
Two concept:
Expected zone
Request zone
Assumption:
Sender has advanced knowledge about location and velocity of the
destination
6. Location-Aided Routing (LAR)
70
71. Location-Aided Routing (LAR)
Expected zone:
determined as a region that is expected to hold the current
location of the destination node (D)
Determination is based on potentially old location information,
and knowledge of the destination’s speed
Request Zone :
Smallest rectangle that include the location of sender and
expected zone.
The sender explicitly defines the request zone ( co-ordinates of
the rectangular request zone)
The nodes can discard a route request packet if it is not under
the request zone.
Route requests limited to a Request Zone that contains
the Expected Zone and location of the sender node (S)71
73. Operation of LAR
Only nodes within the request zone forward route requests
NodeA does not forward RREQ, but node B does
Request zone explicitly specified in the route request
Each node must know its physical location to determine whether it is within the
request zone
If route discovery using the smaller request zone fails to find a route,the
sender initiates another route discovery (after a timeout) using a larger
request zone
the larger request zone may be the entire network
Rest of route discovery protocol similar to DSR
73
74. Operation of LAR
When Destination node (D) receives the route request message, it
replies by sending a route reply message (as in the flooding
algorithm).
Node D includes its current location and current time in the route
reply message.
When node S receives this route reply message (ending its route discovery), it
records the location of node D.
Node S can use this information to determine the request zone for a future
route discovery.
74
75. LAR: Summary
Advantages
Limit the search for a new route to a smaller request zone.
Reduces the scope of route request flood
Reduce the signaling traffic
Reduces overhead of route discovery
Disadvantage
Nodes need to know their physical locations
GPS is needed for pre-knowledge of the location of the destination
Positional error may affect routing
Does not take into account possible existence of obstructions for radio
transmissions75
77. Why POWER concerns ?
The lifetime of a network is defined as the time it takes for a fixed
percentage of the nodes in a network to die out.
Portability of wireless nodes being critical its almost mandatory to keep the
battery sizes to a bare necessary.
Since battery capacity is fixed, a wireless mobile node is
extremely energy constrained
Hence all network related transactions should be power aware to be able to
make efficient use of the overall energy resources of the network
77
78. Metrics ( objectives)
Battery life is taken as routing metric
1. Minimize energy consumed / packet
2. Maximize time to Network Partition
3. Minimize variance in node power levels
4. Minimize cost / packet
5. Minimize maximum node cost
78
81. Hybrid protocol of reactive and proactive approach
Disadvantage of reactive:
reactive protocols have higher latency in discovering
routes.
Disadvantage of proactive:
proactive protocols generate a high volume of control
messages required for updating local routing tables.
ZRP:
The proactive part of the protocol is restricted to a small neighbourhood
of a node and the reactive part is used for routing across the network.
This reduces latency in route discovery and reduces the number
of control messages as well.
81
82. 82
ZRP: Zone routing protocol
Hybrid of table-driven and on-demand!!
From each node, there is a concept of “zone”.
Within each zone, the routing is performed in a table-driven manner
(proactive), similar to DSDV.
However, a node does not try to keep global routing information.
For inter-zone routing, on-demand routing is used.
This is similar to DSR.
83. Zone routing protocol
A routing zone :
Comprises a few mobile ad hoc nodes within one, two, or more hops
away from where the central node is formed.
Zones can overlap.
Each node specifies a zone radius in terms of radio hops.
Similar to a cluster with the exception that every node acts as a cluster
head and a member of other clusters.
Within this zone, a table-driven-based routing protocol is used.
Each node, therefore, has a route to all other nodes within the zone.
If the destination node resides outside the source zone, an on-
demand search-query routing method is used.
83
85. ZRP
ZRP has three sub-protocols:
the proactive (table-driven) Intrazone Routing Protocol
(IARP),
the reactive Interzone Routing Protocol (IERP), and
the Bordercast Resolution Protocol (BRP).
a) Intrazone Routing Protocol (IARP)
the proactive (table-driven) approach
IARP can be implemented using existing link-state or distance-vector
routing.
ZRP's IARP relies on an underlying neighbor discovery protocol to
detect the presence and absence of neighboring nodes
Ensure that each node within the zone has a consistent routing table to
reflect up-to-date information
85
86. ZRP
b) Reactive Interzone Routing Protocol (IERP), and
Relies on border nodes to perform on-demand routing to search for routing
information to nodes residing outside its current zone.
IERP uses the bordercast resolution protocol.
c) the Bordercast Resolution Protocol (BRP).
Instead of allowing the query broadcast to penetrate into nodes within other zones,
the border nodes in other zones that receive this message will not propagate it
further.
Relies on border nodes to perform on-demand routing to search for routing
information to nodes residing outside its current zone.
Without proper query control, ZRP can actually perform worse than
standard flooding-based protocols
86
87. ZRP
ZRP's route discovery process is, route table lookup and/or
interzone route query search.
When a route is broken due to node mobility,
if the source of the mobility is within the zone
it will be treated like a link change event and an event-driven route
updates used in proactive routing will inform all other nodes in the zone.
If the source of mobility is a result of the border node or other
zone nodes,
then route repair in the form of a route query search is performed, or in
the worst case, the source node is informed of route failure.
87
89. Proactive routing protocol
Does not need routing updates
Does not attempts to maintain optimum path
Examines updating strategies used table driven routing approaches
like ORA
Each node maintains a source tree
Source tree is the set of links used by an ad hoc host in its preferred
path to destination
Aggregation is done on host adjacent links and the source trees of the
neighbours. Aggregation creates a partial topology graph
Each node runs route selection algorithm on its own source node tree to
derive a routing table which can specifies the successor to each
destination
Uses sequence numbers to validate link state updates (LSU)
A host accepts a LSU if the sequence number is higher than the
previous or there is no entry till.
Only changes to the validity of the tree are propagated.
Dijkstra’s shortest path algorithm is used to select routes.
89
91. Estimates the distance between two nodes using the relative distance
estimation algorithm in radio hops.
It is a source initiated routing protocol
It limits the range of route searching in order to save the cost of flooding a
route request message into the entire wireless area.
It is assumed in RDMAR that all ad hoc mobile hosts are migrating at the
same fixed speed.
Route Discovery
Transmission of route discovery packets
If a current relative estimate is present then search flood is limited to
this distance
Destination node returns reply message over reverse path.
Reply message moves backward while intermediate nodes establish the
forward route hop-by-hop
91
92. Route maintenance
The node that notifies a link breakage invokes localized route
discovery to find partial path to destination.
If link breakage location is closer to the sender then the route
failure message is sent to the source.
The intermediate nodes which have the routing information
regarding this linkage , must have to remove their entries from
the routing tables.
It is assumed that all links are bidirectional
It uses the shortest route as the routing metric.
92
93. 93
Summary
On-demand AODV DSR TORA ABR SSA
Overall complexity Medium Medium High High High
Overhead Low Medium Medium High High
Routing philosophy Flat Flat Flat Flat Flat
Loop-free Yes Yes Yes Yes Yes
Multicast capability Yes No No No No
Beaconing requirements No No No Yes yes
Multiple route support No Yes Yes No No
Routes maintained in Route table Route cache Route table Route table Route
table
Route reconfiguration
methodlogy
Erase route;
notify source
Erase route;
notify
source
Link
reversal;
route repair
Localized
broadcast
query
Erase
route;
notify
source
Routing metric Freshest and
shortest path
Shortest
path
Shortest
path
Associativity
and shortest
path and
others
Associati
vity and
widest
Comparisons of the characteristics of source-initiated on demand routing protocol
94. 94
Overview
Parameters On Demand Table Driven
Availability of Routing
Information
Available when needed Always available regardless of need
Routing Philosophy Flat Mostly Flat except for CGSR
Periodic route updates Not Required Yes
Coping with Mobility Using Localized route discovery in
ABR
Inform other nodes to achieve
consistent routing tables
SignalingTraffic Generated Grows with increasing mobility of
active nodes as in ABR
Greater than that of On Demand
Routing
QoS Support Few Can Support QoS Mainly Shortest Path as QoS Metric
95. Reference
1. Routing Protocols for Ad Hoc Mobile Wireless Networt by Padmini Misra,
ftp://ftp.netlab.ohio-state.edu/pub/jain/courses/cis788-
99/adhoc_routing/index.html#CBRP
2. A Comparison of On-Demand and Table Driven Routing for Ad-Hoc Wireless
Networks, by Jyoti Raju and J.J. Garcia-Luna-Aceves,
http://www.soe.ucsc.edu/~jyoti/paper2/
3. A New Routing Protocol for the Reconfigurable Wireless Networks, Zygmunt J Hass
4. Caching strategies in on-demand routing protocols for wireless ad hoc networks, by
Yih-chun hu and Divid B. Johnson, http://monarch.cs.cmu.edu
5. Highly Dynamic Destination-Sequenced Distance-Vector Routing for Mobile
Computers, Pravin Bhagwat, Charles E. Perkins
6. Dynamic source routing in ad hoc wireless networks, by David B. Johnson and David
A. Maltz, http://www1.ics.uci.edu/~atm/adhoc/paper-collection/johnson-dsr.pdf
7. A Performace Comparison of Multi-Hop Wireless Ad Hoc Network Routing
Protocols, Josh Broch etc
8. An Efficient Routing Protocol for Wireless Netwrok, Shree Murthy etc
9. Temporally-Ordered Routing Algorithm (TORA) Version 1 Funtional
Specification, by V. Park, S. Corson, http://www1.ics.uci.edu/~atm/adhoc/paper-
collection/corson-draft-ietf-manet-tora-spec-00.txt
10. Ad Hoc On Demand Distance Vector (AODV) Routing, by Charles Perkins,
http://www1.ics.uci.edu/~atm/adhoc/paper-collection/perkins-draft-ietf-manet-aodv-
00.txt95
96. Reference (cont.)
7. An Introduction to Mobile Ad Hoc Network, by MingYu Jiang,
http://kiki.ee.ntu.edu.tw/mmnet1/adhoc/
8. Scalable Routing Strategies for Ad hocWireless Network, by Atsushi Iwata , Ching-
Chuan Chiang etc.
9. A Performance Comparison of Multi-HopWireless Ad Hoc Network Routing
Protocols, by Josh Broch, David A. Maltz, David B. Johnson,Yih-Chun Hu, Jorjeta
Jetcheva, http://www1.ics.uci.edu/~atm/adhoc/paper-collection/johnson-
performance-comparison-mobicom98.pdf
10. Fisheye State Routing:A Routing Schema for Ad HocWireless Networks, by guangyu
Pei, Mario Gerla,Tsi-Wei Chen
11. A review of current Routing protocols for ad-hoc MobileWireless Networks, by
Elizabeth M. Royer and C-KToh
http://www.cs.ucsb.edu/~vigna/courses/CS595_Fall01/royer99review.pdf
12. CEDAR: a Core-Extraction distributed Ad Hoc Routing Algorithm, Prasun Sinha,
Vaduvur Nharghavan, etc
13. Mobile computing today & in the future, by M.J. Fahham and M.K. Hauge.
http://www.doc.ic.ac.uk/~nd/surprise_95/journal/vol4/mjf/report.html
14. Performance Comparison of On-demand Routing Protocols in Ad Hoc Network by
Sohela Kaniz http://fiddle.visc.vt.edu/courses/ecpe6504-
wireless/projects_spring2000/pres_kaniz.pdf
96