A Retrial Queueing Model with Scheduling Admission Control in QoS Supporting ...IJCNCJournal
Optical burst switching (OBS) is being considered as an optical transmission technology that meets the increasing bandwidth demands and requirements of quality of service (QoS) of the next generation alloptical Internet. Due to technological limitations such as optical buffers are not yet available at core nodes, ensuring QoS in OBS networks is difficult to perform flexibly compared to electronic networks (e.g. IP network). In this paper, a combination of the prediction based on burst traffic and fibre delay links (FDL) is proposed to allocate wavelengths properly, ensuring QoS and improving the network performance. Efficiency evaluations based on mathematical analysis and simulation will confirm the advantages of our proposed model.
Dynamic bandwidth allocation scheme in lr pon with performance modelling and ...IJCNCJournal
We consider models of telecommunication systems that incorporate probability, dense real-time and data.
We present a new formal abstraction method for computing minimum and maximum reachability
probabilities for such models. Our approach uses strictly local formal abstract steps to reduce both the size
of abstract specifications generated and the complexity of operations needed, in comparison to previous
approaches of this kind. A selection of large case studies are implemented the techniques and evaluate,
which include some infinite-state probabilistic real time models, demonstrating improvements over existing
tools in several cases. The capacity of metro and access networks are extended the reach and split ratio of
the conventional Long - Reach Passive Optical Networks (LR-PONs). The efficient solutions of LR-PONs
are appeared in feeder distances around 100km and high split ratios up to 1000-way . Among many
existing approaches, one of the most effective options to improve network performance in LR-PONs are the
multi-thread based dynamic bandwidth allocation (DBA) scheme where several bandwidth allocation
processes are performed in parallel is considered. Without proper intercommunication between the
overlapped threads, multi-thread DBA may lose efficiency and even perform worse than the conventional
single thread algorithm. Real Time Probabilistic Systems are used to evaluate a typical PON systems
performance. This approach is more convenient, flexible, and lower cost than the former simulation method,
which do not need develop special hardware and software tools. Moreover, how changes in performance
depend on changes in the particular modes can be easily analysis by supplying ranges for parameter values.
The proposed algorithm with traditional DBA is compared, and shows its advantage on average packet
delay. The key parameters of the algorithm are analysed and optimized, such as initiating and tuning
multiple threads, inter -thread scheduling, and fairness among users. The algorithms advantage in
numerical results are decreased the average packet delay and improve network throughput under varying
offered loads.
Analysing Mobile Random Early Detection for Congestion Control in Mobile Ad-h...IJECEIAES
This research paper suggests and analyse a technique for congestion control in mobile ad hoc networks. The technique is based on a new hybrid approach that uses clustering and queuing techniques. In clustering, in general cluster head transfers the data, following a queuing method based on a RED (Random Early Detection), the mobile environment makes it Mobile RED (or MRED), It majorly depends upon mobility of nodes and mobile environments leads to unpredictable queue size. To simulate this technique, the Network Simulator 2 (or NS2) is used for various scenarios. The simulated results are compared with NRED (Neighbourhood Random Early Detection) queuing technique of congestion control. It has been observed that the results are improved using MRED comparatively.
A Bandwidth Efficient Scheduling Framework for Non Real Time Applications in ...ijdpsjournal
The key concern on the bandwidth allocation and scheduling for non real time traffic are the fulfillment of its minimum throughput requirement and improvement of bandwidth utilization with acceptable delay. This paper proposes a simple and efficient scheduling framework for allocating bandwidth to non real time
polling service (nrtPS) users in IEEE 802.16 networks. In this framework, jointly selective repeat ARQ at the MAC layer and adaptive modulation and coding techniques at the physical are considered. Numerical simulations demonstrate that the proposed scheduling approach provides a graceful compromise between bandwidth utilization and packet delivery delay while maintaining the minimum throughput requirements of nrtPS applications. Thus proves the efficiency of the proposed framework. The simulation is done for unicast scenario.
Optimized Cluster Establishment and Cluster-Head Selection Approach in WSNIJCNCJournal
In recent years, limited resources of user products and energy-saving are recognized as the major challenges of Wireless Sensor Networks (WSNs). Clustering is a practical technique that can reduce all energy consumption and provide stability of workload that causes a larger difference in energy depletion among other nodes and cluster heads (CHs). In addition, clustering is the solution of energy-efficient for maximizing the network longevity and improvising energy efficiency. In this paper, a novel OCE-CHS (Optimized Cluster Establishment and Cluster-Head Selection) approach for sensor nodes is represented to improvise the packet success ratio and reduce the average energy-dissipation. The main contribution of this paper is categorized into two processes, first, the clustering algorithm is improvised that periodically chooses the optimal set of the CHs according to the speed of the average node and average-node energy. This is considerably distinguished from node-based clustering that utilizes a distributed clustering algorithm to choose CHs based on the speed of the current node and remaining node energy. Second, more than one factor is assumed for the detached node to join the optimal cluster. In the result section, we discuss our clustering protocols implementation of optimal CH-selection to evade the death of SNs, maximizing throughput, and further improvise the network lifetime by minimizing energy consumption.
Nearest Adjacent Node Discovery Scheme for Routing Protocol in Wireless Senso...IOSR Journals
The broad significance of Wireless Sensor Networks is in most emergency and disaster rescue
domain. The routing process is the main challenges in the wireless sensor network due to lack of physical links.
The objective of routing is to find optimum path which is used to transferring packets from source node to
destination node. Routing should generate feasible routes between nodes and send traffic along the selected path
and also achieve high performance. This paper presents a nearest adjacent node scheme based on shortest path
routing algorithm. It is plays an important role in energy conservation. It finds the best location of nearest
adjacent nodes by involving the least number of nodes in transmission of data and set large number of nodes to
sleep in idle mode. Based on simulation result we shows the significant improvement in energy saving and
enhance the life of the network
A Retrial Queueing Model with Scheduling Admission Control in QoS Supporting ...IJCNCJournal
Optical burst switching (OBS) is being considered as an optical transmission technology that meets the increasing bandwidth demands and requirements of quality of service (QoS) of the next generation alloptical Internet. Due to technological limitations such as optical buffers are not yet available at core nodes, ensuring QoS in OBS networks is difficult to perform flexibly compared to electronic networks (e.g. IP network). In this paper, a combination of the prediction based on burst traffic and fibre delay links (FDL) is proposed to allocate wavelengths properly, ensuring QoS and improving the network performance. Efficiency evaluations based on mathematical analysis and simulation will confirm the advantages of our proposed model.
Dynamic bandwidth allocation scheme in lr pon with performance modelling and ...IJCNCJournal
We consider models of telecommunication systems that incorporate probability, dense real-time and data.
We present a new formal abstraction method for computing minimum and maximum reachability
probabilities for such models. Our approach uses strictly local formal abstract steps to reduce both the size
of abstract specifications generated and the complexity of operations needed, in comparison to previous
approaches of this kind. A selection of large case studies are implemented the techniques and evaluate,
which include some infinite-state probabilistic real time models, demonstrating improvements over existing
tools in several cases. The capacity of metro and access networks are extended the reach and split ratio of
the conventional Long - Reach Passive Optical Networks (LR-PONs). The efficient solutions of LR-PONs
are appeared in feeder distances around 100km and high split ratios up to 1000-way . Among many
existing approaches, one of the most effective options to improve network performance in LR-PONs are the
multi-thread based dynamic bandwidth allocation (DBA) scheme where several bandwidth allocation
processes are performed in parallel is considered. Without proper intercommunication between the
overlapped threads, multi-thread DBA may lose efficiency and even perform worse than the conventional
single thread algorithm. Real Time Probabilistic Systems are used to evaluate a typical PON systems
performance. This approach is more convenient, flexible, and lower cost than the former simulation method,
which do not need develop special hardware and software tools. Moreover, how changes in performance
depend on changes in the particular modes can be easily analysis by supplying ranges for parameter values.
The proposed algorithm with traditional DBA is compared, and shows its advantage on average packet
delay. The key parameters of the algorithm are analysed and optimized, such as initiating and tuning
multiple threads, inter -thread scheduling, and fairness among users. The algorithms advantage in
numerical results are decreased the average packet delay and improve network throughput under varying
offered loads.
Analysing Mobile Random Early Detection for Congestion Control in Mobile Ad-h...IJECEIAES
This research paper suggests and analyse a technique for congestion control in mobile ad hoc networks. The technique is based on a new hybrid approach that uses clustering and queuing techniques. In clustering, in general cluster head transfers the data, following a queuing method based on a RED (Random Early Detection), the mobile environment makes it Mobile RED (or MRED), It majorly depends upon mobility of nodes and mobile environments leads to unpredictable queue size. To simulate this technique, the Network Simulator 2 (or NS2) is used for various scenarios. The simulated results are compared with NRED (Neighbourhood Random Early Detection) queuing technique of congestion control. It has been observed that the results are improved using MRED comparatively.
A Bandwidth Efficient Scheduling Framework for Non Real Time Applications in ...ijdpsjournal
The key concern on the bandwidth allocation and scheduling for non real time traffic are the fulfillment of its minimum throughput requirement and improvement of bandwidth utilization with acceptable delay. This paper proposes a simple and efficient scheduling framework for allocating bandwidth to non real time
polling service (nrtPS) users in IEEE 802.16 networks. In this framework, jointly selective repeat ARQ at the MAC layer and adaptive modulation and coding techniques at the physical are considered. Numerical simulations demonstrate that the proposed scheduling approach provides a graceful compromise between bandwidth utilization and packet delivery delay while maintaining the minimum throughput requirements of nrtPS applications. Thus proves the efficiency of the proposed framework. The simulation is done for unicast scenario.
Optimized Cluster Establishment and Cluster-Head Selection Approach in WSNIJCNCJournal
In recent years, limited resources of user products and energy-saving are recognized as the major challenges of Wireless Sensor Networks (WSNs). Clustering is a practical technique that can reduce all energy consumption and provide stability of workload that causes a larger difference in energy depletion among other nodes and cluster heads (CHs). In addition, clustering is the solution of energy-efficient for maximizing the network longevity and improvising energy efficiency. In this paper, a novel OCE-CHS (Optimized Cluster Establishment and Cluster-Head Selection) approach for sensor nodes is represented to improvise the packet success ratio and reduce the average energy-dissipation. The main contribution of this paper is categorized into two processes, first, the clustering algorithm is improvised that periodically chooses the optimal set of the CHs according to the speed of the average node and average-node energy. This is considerably distinguished from node-based clustering that utilizes a distributed clustering algorithm to choose CHs based on the speed of the current node and remaining node energy. Second, more than one factor is assumed for the detached node to join the optimal cluster. In the result section, we discuss our clustering protocols implementation of optimal CH-selection to evade the death of SNs, maximizing throughput, and further improvise the network lifetime by minimizing energy consumption.
Nearest Adjacent Node Discovery Scheme for Routing Protocol in Wireless Senso...IOSR Journals
The broad significance of Wireless Sensor Networks is in most emergency and disaster rescue
domain. The routing process is the main challenges in the wireless sensor network due to lack of physical links.
The objective of routing is to find optimum path which is used to transferring packets from source node to
destination node. Routing should generate feasible routes between nodes and send traffic along the selected path
and also achieve high performance. This paper presents a nearest adjacent node scheme based on shortest path
routing algorithm. It is plays an important role in energy conservation. It finds the best location of nearest
adjacent nodes by involving the least number of nodes in transmission of data and set large number of nodes to
sleep in idle mode. Based on simulation result we shows the significant improvement in energy saving and
enhance the life of the network
An improved ant colony optimization algorithm for wire optimizationjournalBEEI
Wire optimization has become one of the greatest challenges in today’s circuit design. This paper presents a method for wire optimization in circuit routing using an improved ant colony optimization with Steiner nodes (ACOSN) algorithm. Circuit delay and power dissipation are primarily affected by the length of the routed wire. Thus, the main goal of this proposed algorithm is to find the shortest route from one point to another using an algorithm that relies on the artificial behavior of ants. The algorithm is implemented in the JAVA programming language. The proposed ACOSN algorithm is compared with the conventional ant colony optimization (ACO) algorithm in terms of efficiency and routing performance when applied to three types of circuits: emitter-coupled logic, 741 output and a cascode amplifier. The performance of the proposed method is analyzed based on circuit information such as total wire routing, total number of nets, total wire reduction, terminals per net and total terminals. From the simulation analysis, it is shown that the proposed ACOSN algorithm gives the most benefit to complex circuits, where it successfully reduces the wire length by 21.52% for a cascode amplifier circuit, 14.49% for a 741 output circuit, and 10.43% for emitter-coupled logic circuit.
Improving Power Efficiency in Cooperative Diversity and Mimo Systems by Using...IJERA Editor
In this paper, we propose a new simple relayingstrategy based on bit-interleaved convolutionally coded starquadrature amplitude modulation (QAM) along with coherent/ noncoherent detection. Exploiting this property, a hard limiter is used to enhance power amplifier (PA) efficiency at the relay.here we are using the higher order modulation for improving relay communication and also employ the accurate relay technique.Moreover, we show that the proposedapproach retains differential detectability, which results in a significant reduction of receiver complexity with robustness against phase ambiguityBy analyzing our proposed method in terms of asymptotic pairwise error probability(PEP),Furthermore, theeffectiveness of the proposed scheme in terms of PA efficiency is confirmed by comparing the statistical distributions of the corresponding instantaneous signal power.and also implement the PEP in MIMO systems for improving the power efficiency.All the theoretical results agree with those obtained by computer simulations.
DYNAMIC CONGESTION CONTROL IN WDM OPTICAL NETWORKcscpconf
This paper is based on Wavelength Division Multiplexing (WDM) optical networking. In this optical networking, prior to data transfer, lightpath establishment between source and
destination nodes is usually carried out through a wavelength reservation protocol. This wavelength is reserved corresponding to a route between the source and destination and the
route is chosen following any standard routing protocol based on shortest path. The backward reservation protocol is implemented initially. A fixed connected and weighted network is
considered. The inputs of this implementation are the fixed network itself and its corresponding shortest path matrix. After this initial level of implementation, the average node usage over a time period is calculated and various thresholds for node usage are considered. Above threshold value, request arriving at that path selects its next shortest path. This concept is
implemented on various wavelengths. The output represents the performance issues of dynamic congestion control.
Efficient Design of p-Cycles for Survivability of WDM Networks Through Distri...CSCJournals
The optical networks provide the backbone infrastructure for telecommunication networks. Because of the high-speed of optical networks, network failure such as a cable cut or node failure may result in a tremendous loss of data and hence revenue received. The p-cycle is a novel approach reported for design of survivable optical WDM networks. They are preconfigured protection structure, combining fast restoration speed of ring and mesh protection efficiency. The main issue in p-cycle network design is to find a set of p-cycles to protect a given working capacity distribution so that total spare capacity used by the p-cycles is minimized. An Integer Linear Programming (ILP) is the most efficient method reported in the literature for designing of optimal p-cycles. Where complexity of ILP increases as the size of network increases, i.e., it is not so efficient in case of large networks. Recently, a new, promising concept to support dynamic demand environments has been introduced by Grover namely, the distributed cycle pre- configuration (DCPC) protocol, which is an adaptation of the processing rule of the self-healing network (SHN). However, it is generally unable to provide 100% protection of the working capacity under Spare Capacity Optimization (SCO) design model. Therefore in this paper we have proposed enhancements in DCPC to increase its protection level under single failure scenario. The main idea behind the proposed enhancement is it to fix the span as a straddle span of a p-cycle where unprotected working capacity is more. From the simulation of test case networks, it is found that the proposed scheme significantly increases ratio of protection under the SCO design model.
Novel Position Estimation using Differential Timing Information for Asynchron...IJCNCJournal
Positioning techniques have been a common objective since the early development of wireless networks. However, current positioning methods in cellular networks, for instance, are still primarily focused on the use of the Global Navigation Satellite System (GNSS), which has several limitations, like high power drainage and failure in indoor scenarios. This study introduces a novel approach employing standard LTE signaling in order to provide high accuracy positioning estimation. The proposed technique is designed in analogy to the human sound localization system, eliminating the need of having information from three spatially diverse Base Stations (BSs). This is inspired by the perfect human 3D sound localization with two ears. A field study is carried out in a dense urban city to verify the accuracy of the proposed technique, with more than 20 thousand measurement samples collected. The achieved positioning accuracy is meeting the latest Federal Communications Commission (FCC) requirements in the planner dimension.
A Summative Comparison of Blind Channel Estimation Techniques for Orthogonal ...IJECEIAES
The OFDM technique i.e. Orthogonal frequency division multiplexing has become prominent in wireless communication since its instruction in 1950’s due to its feature of combating the multipath fading and other losses. In an OFDM system, a large number of orthogonal, overlapping, narrow band subchannels or subcarriers, transmitted in parallel, divide the available transmission bandwidth. The separation of the subcarriers is theoretically optimal such that there is a very compact spectral utilization. This paper reviewed the possible approaches for blind channel estimation in the light of the improved performance in terms of speed of convergence and complexity. There were various researches which adopted the ways for channel estimation for Blind, Semi Blind and trained channel estimators and detectors. Various ways of channel estimation such as Subspace, iteration based, LMSE or MSE based (using statistical methods), SDR, Maximum likelihood approach, cyclostationarity, Redundancy and Cyclic prefix based. The paper reviewed all the above approaches in order to summarize the outcomes of approaches aimed at optimum performance for channel estimation in OFDM systems.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
PERFORMANCE ANALYSIS IN CELLULAR NETWORKS CONSIDERING THE QOS BY RETRIAL QUEU...IJCNCJournal
In this article, a retrial queueing model will be considered with persevering customers for wireless cellular
networks which can be frequently applied in the Fractional Guard Channel (FGC) policies, including
Limited FGC (LFGC), Uniform FGC (UFGC), Limited Average FGC (LAFGC) and Quasi Uniform FGC
(QUFGC). In this model, the examination on the retrial phenomena permits the analyses of important
effectiveness measures pertained to the standard of services undergone by users with the probability that a
fresh call first arrives the system and find all busy channels at the time, the probability that a fresh call
arrives the system from the orbit and find all busy channels at the time and the probability that a handover
call arrives the system and find all busy channels at the time. Comparison between four types of the FGC
policy can befound to evaluate the performance of the system.
Efficient energy, cost reduction, and QoS based routing protocol for wireless...IJECEIAES
Recent developments and widespread in wireless sensor network have led to many routing protocols, many of these protocols consider the efficiency of energy as the ultimate factor to maximize the WSN lifetime. The quality of Service (QoS) requirements for different applications of wireless sensor networks has posed additional challenges. Imaging and data transmission needs both QoS aware routing and energy to ensure the efficient use of sensors. In this paper, we propose an Efficient, Energy-Aware, Least Cost, (ECQSR) quality of service routing protocol for sensor networks which can run efficiently with best-effort traffic processing. The protocol aims to maximize the lifetime of the network out of balancing energy consumption across multiple nodes, by using the concept of service differentiation, finding lower cost by finding the shortest path using nearest neighbor algorithm (NN), also put certain constraints on the delay of the path for real-time data from where link cost that captures energy nodes reserve, energy of the transmission, error rate and other parameters. The results show that the proposed protocol improves the network lifetime and low power consumption.
ENERGY EFFICIENT ROUTING PROTOCOL BASED ON DSRijasuc
Energy consumption is a major concern in most of the present day devices in wireless networks. Especially
in Ad hoc networks, energy is a limited factor. Random movement in nodes add to the frequent failure of
routes which adds to the energy consumption in the network. In this paper, a routing protocol is proposed
which is based on a modification of the conventional DSR (Dynamic Source routing). A comparative
analysis is performed with respect to energy consumption, maximum throughput and delay. The routing
protocols used for reference in this analysis are DSDV, AODV and conventional DSR. Experimental results
show that the proposed modified DSR shows a reduced energy consumption, improved rate of maximum
throughput and a reduced delay compared to above mentioned routing protocols
A Cluster-Based Routing Protocol and Fault Detection for Wireless Sensor NetworkIJCNCJournal
In Wireless Sensors Networks (WSN) based application, a large number of sensor devices must be deployed. Energy efficiency and network lifetime are the two most challenging issues in WSN. As a consequence, the main goal is to reduce the overall energy consumption using clustering protocols which have to ensure reliability and connectivity in large-scale WSN. This work presents a new clustering and routing algorithm based on the properties of the sensor networks. The main goal of this work is to extend the network lifetime via charge equilibration in the WSN. According to many errors with sensing devices and to have greater data accuracy, we use a quorum mechanism. The proposed algorithms are evaluated widely and the results are compared with related works. The experimental results show that the proposed algorithm provides an effective improvement in terms of energy consumption, data accuracy and network lifetime.
A Novel Path Tracing Scheme In All-Optical Networks Using Benes NetworkCSCJournals
A novel path tracing scheme is described in this paper which is known as Prime number encoding scheme using Benes network. In this scheme every data packet consist a label which is default 1 and every node consist of a prime number tag, as this data packet pass through the network label will be multiplied with the tag of the node. Prime number multiplication is done with encoder. At the receiver end factorization is done which gives the information of travelled path. In this scheme optical cross connects (OXC) is replaced with the Benes network which gives the better result than OXC. System having Benes network gives less attenuation than OXC and complexity of the system also decreases.
ROUTING IN OPTICAL MESH NETWORKS-A QOS PERSPECTIVEijasuc
Wireless Ad-Hoc Mesh Networks are characterized by static nodes connected in a mesh topology. A routing
protocol discovers and maintains the route for successful transmission of data in a network. The routing
protocol should also provide load balancing and fault tolerance for improved network performance. In
Free Space Optical networks (FSO) line of sight (LOS) should be maintained between the two
communicating nodes. In a multihop scenario maintaining LOS during routing is a challenge. In this paper
we propose a routing protocol Quality of Service-Directional Routing Protocol (QDRP) - which assures a
certain level of performance to a data flow in terms of delay and implemented on FSO MANET. Through
simulations it is observed that QDRP chooses the path with the least delay and performs satisfactorily
under varying node densities and transmission rates achieving end to end delay of .14 s and packet delivery
percentage of 96% when simulated for an area of 1300 m *1300 m for 100 nodes. This work explores the
potential of the proposed routing protocol for free space optical mesh networks. QDRP is compared with
ORRP (Orthogonal Rendezvous Routing Protocol) and AODV (Ad-Hoc on Demand Distance Vector), a
reactive protocol which is also implemented in free space optical environment. We support our conclusions
that QDRP gains in terms of packet delivery percentage, end to end delay and goodput.
An improved ant colony optimization algorithm for wire optimizationjournalBEEI
Wire optimization has become one of the greatest challenges in today’s circuit design. This paper presents a method for wire optimization in circuit routing using an improved ant colony optimization with Steiner nodes (ACOSN) algorithm. Circuit delay and power dissipation are primarily affected by the length of the routed wire. Thus, the main goal of this proposed algorithm is to find the shortest route from one point to another using an algorithm that relies on the artificial behavior of ants. The algorithm is implemented in the JAVA programming language. The proposed ACOSN algorithm is compared with the conventional ant colony optimization (ACO) algorithm in terms of efficiency and routing performance when applied to three types of circuits: emitter-coupled logic, 741 output and a cascode amplifier. The performance of the proposed method is analyzed based on circuit information such as total wire routing, total number of nets, total wire reduction, terminals per net and total terminals. From the simulation analysis, it is shown that the proposed ACOSN algorithm gives the most benefit to complex circuits, where it successfully reduces the wire length by 21.52% for a cascode amplifier circuit, 14.49% for a 741 output circuit, and 10.43% for emitter-coupled logic circuit.
Improving Power Efficiency in Cooperative Diversity and Mimo Systems by Using...IJERA Editor
In this paper, we propose a new simple relayingstrategy based on bit-interleaved convolutionally coded starquadrature amplitude modulation (QAM) along with coherent/ noncoherent detection. Exploiting this property, a hard limiter is used to enhance power amplifier (PA) efficiency at the relay.here we are using the higher order modulation for improving relay communication and also employ the accurate relay technique.Moreover, we show that the proposedapproach retains differential detectability, which results in a significant reduction of receiver complexity with robustness against phase ambiguityBy analyzing our proposed method in terms of asymptotic pairwise error probability(PEP),Furthermore, theeffectiveness of the proposed scheme in terms of PA efficiency is confirmed by comparing the statistical distributions of the corresponding instantaneous signal power.and also implement the PEP in MIMO systems for improving the power efficiency.All the theoretical results agree with those obtained by computer simulations.
DYNAMIC CONGESTION CONTROL IN WDM OPTICAL NETWORKcscpconf
This paper is based on Wavelength Division Multiplexing (WDM) optical networking. In this optical networking, prior to data transfer, lightpath establishment between source and
destination nodes is usually carried out through a wavelength reservation protocol. This wavelength is reserved corresponding to a route between the source and destination and the
route is chosen following any standard routing protocol based on shortest path. The backward reservation protocol is implemented initially. A fixed connected and weighted network is
considered. The inputs of this implementation are the fixed network itself and its corresponding shortest path matrix. After this initial level of implementation, the average node usage over a time period is calculated and various thresholds for node usage are considered. Above threshold value, request arriving at that path selects its next shortest path. This concept is
implemented on various wavelengths. The output represents the performance issues of dynamic congestion control.
Efficient Design of p-Cycles for Survivability of WDM Networks Through Distri...CSCJournals
The optical networks provide the backbone infrastructure for telecommunication networks. Because of the high-speed of optical networks, network failure such as a cable cut or node failure may result in a tremendous loss of data and hence revenue received. The p-cycle is a novel approach reported for design of survivable optical WDM networks. They are preconfigured protection structure, combining fast restoration speed of ring and mesh protection efficiency. The main issue in p-cycle network design is to find a set of p-cycles to protect a given working capacity distribution so that total spare capacity used by the p-cycles is minimized. An Integer Linear Programming (ILP) is the most efficient method reported in the literature for designing of optimal p-cycles. Where complexity of ILP increases as the size of network increases, i.e., it is not so efficient in case of large networks. Recently, a new, promising concept to support dynamic demand environments has been introduced by Grover namely, the distributed cycle pre- configuration (DCPC) protocol, which is an adaptation of the processing rule of the self-healing network (SHN). However, it is generally unable to provide 100% protection of the working capacity under Spare Capacity Optimization (SCO) design model. Therefore in this paper we have proposed enhancements in DCPC to increase its protection level under single failure scenario. The main idea behind the proposed enhancement is it to fix the span as a straddle span of a p-cycle where unprotected working capacity is more. From the simulation of test case networks, it is found that the proposed scheme significantly increases ratio of protection under the SCO design model.
Novel Position Estimation using Differential Timing Information for Asynchron...IJCNCJournal
Positioning techniques have been a common objective since the early development of wireless networks. However, current positioning methods in cellular networks, for instance, are still primarily focused on the use of the Global Navigation Satellite System (GNSS), which has several limitations, like high power drainage and failure in indoor scenarios. This study introduces a novel approach employing standard LTE signaling in order to provide high accuracy positioning estimation. The proposed technique is designed in analogy to the human sound localization system, eliminating the need of having information from three spatially diverse Base Stations (BSs). This is inspired by the perfect human 3D sound localization with two ears. A field study is carried out in a dense urban city to verify the accuracy of the proposed technique, with more than 20 thousand measurement samples collected. The achieved positioning accuracy is meeting the latest Federal Communications Commission (FCC) requirements in the planner dimension.
A Summative Comparison of Blind Channel Estimation Techniques for Orthogonal ...IJECEIAES
The OFDM technique i.e. Orthogonal frequency division multiplexing has become prominent in wireless communication since its instruction in 1950’s due to its feature of combating the multipath fading and other losses. In an OFDM system, a large number of orthogonal, overlapping, narrow band subchannels or subcarriers, transmitted in parallel, divide the available transmission bandwidth. The separation of the subcarriers is theoretically optimal such that there is a very compact spectral utilization. This paper reviewed the possible approaches for blind channel estimation in the light of the improved performance in terms of speed of convergence and complexity. There were various researches which adopted the ways for channel estimation for Blind, Semi Blind and trained channel estimators and detectors. Various ways of channel estimation such as Subspace, iteration based, LMSE or MSE based (using statistical methods), SDR, Maximum likelihood approach, cyclostationarity, Redundancy and Cyclic prefix based. The paper reviewed all the above approaches in order to summarize the outcomes of approaches aimed at optimum performance for channel estimation in OFDM systems.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
PERFORMANCE ANALYSIS IN CELLULAR NETWORKS CONSIDERING THE QOS BY RETRIAL QUEU...IJCNCJournal
In this article, a retrial queueing model will be considered with persevering customers for wireless cellular
networks which can be frequently applied in the Fractional Guard Channel (FGC) policies, including
Limited FGC (LFGC), Uniform FGC (UFGC), Limited Average FGC (LAFGC) and Quasi Uniform FGC
(QUFGC). In this model, the examination on the retrial phenomena permits the analyses of important
effectiveness measures pertained to the standard of services undergone by users with the probability that a
fresh call first arrives the system and find all busy channels at the time, the probability that a fresh call
arrives the system from the orbit and find all busy channels at the time and the probability that a handover
call arrives the system and find all busy channels at the time. Comparison between four types of the FGC
policy can befound to evaluate the performance of the system.
Efficient energy, cost reduction, and QoS based routing protocol for wireless...IJECEIAES
Recent developments and widespread in wireless sensor network have led to many routing protocols, many of these protocols consider the efficiency of energy as the ultimate factor to maximize the WSN lifetime. The quality of Service (QoS) requirements for different applications of wireless sensor networks has posed additional challenges. Imaging and data transmission needs both QoS aware routing and energy to ensure the efficient use of sensors. In this paper, we propose an Efficient, Energy-Aware, Least Cost, (ECQSR) quality of service routing protocol for sensor networks which can run efficiently with best-effort traffic processing. The protocol aims to maximize the lifetime of the network out of balancing energy consumption across multiple nodes, by using the concept of service differentiation, finding lower cost by finding the shortest path using nearest neighbor algorithm (NN), also put certain constraints on the delay of the path for real-time data from where link cost that captures energy nodes reserve, energy of the transmission, error rate and other parameters. The results show that the proposed protocol improves the network lifetime and low power consumption.
ENERGY EFFICIENT ROUTING PROTOCOL BASED ON DSRijasuc
Energy consumption is a major concern in most of the present day devices in wireless networks. Especially
in Ad hoc networks, energy is a limited factor. Random movement in nodes add to the frequent failure of
routes which adds to the energy consumption in the network. In this paper, a routing protocol is proposed
which is based on a modification of the conventional DSR (Dynamic Source routing). A comparative
analysis is performed with respect to energy consumption, maximum throughput and delay. The routing
protocols used for reference in this analysis are DSDV, AODV and conventional DSR. Experimental results
show that the proposed modified DSR shows a reduced energy consumption, improved rate of maximum
throughput and a reduced delay compared to above mentioned routing protocols
A Cluster-Based Routing Protocol and Fault Detection for Wireless Sensor NetworkIJCNCJournal
In Wireless Sensors Networks (WSN) based application, a large number of sensor devices must be deployed. Energy efficiency and network lifetime are the two most challenging issues in WSN. As a consequence, the main goal is to reduce the overall energy consumption using clustering protocols which have to ensure reliability and connectivity in large-scale WSN. This work presents a new clustering and routing algorithm based on the properties of the sensor networks. The main goal of this work is to extend the network lifetime via charge equilibration in the WSN. According to many errors with sensing devices and to have greater data accuracy, we use a quorum mechanism. The proposed algorithms are evaluated widely and the results are compared with related works. The experimental results show that the proposed algorithm provides an effective improvement in terms of energy consumption, data accuracy and network lifetime.
A Novel Path Tracing Scheme In All-Optical Networks Using Benes NetworkCSCJournals
A novel path tracing scheme is described in this paper which is known as Prime number encoding scheme using Benes network. In this scheme every data packet consist a label which is default 1 and every node consist of a prime number tag, as this data packet pass through the network label will be multiplied with the tag of the node. Prime number multiplication is done with encoder. At the receiver end factorization is done which gives the information of travelled path. In this scheme optical cross connects (OXC) is replaced with the Benes network which gives the better result than OXC. System having Benes network gives less attenuation than OXC and complexity of the system also decreases.
ROUTING IN OPTICAL MESH NETWORKS-A QOS PERSPECTIVEijasuc
Wireless Ad-Hoc Mesh Networks are characterized by static nodes connected in a mesh topology. A routing
protocol discovers and maintains the route for successful transmission of data in a network. The routing
protocol should also provide load balancing and fault tolerance for improved network performance. In
Free Space Optical networks (FSO) line of sight (LOS) should be maintained between the two
communicating nodes. In a multihop scenario maintaining LOS during routing is a challenge. In this paper
we propose a routing protocol Quality of Service-Directional Routing Protocol (QDRP) - which assures a
certain level of performance to a data flow in terms of delay and implemented on FSO MANET. Through
simulations it is observed that QDRP chooses the path with the least delay and performs satisfactorily
under varying node densities and transmission rates achieving end to end delay of .14 s and packet delivery
percentage of 96% when simulated for an area of 1300 m *1300 m for 100 nodes. This work explores the
potential of the proposed routing protocol for free space optical mesh networks. QDRP is compared with
ORRP (Orthogonal Rendezvous Routing Protocol) and AODV (Ad-Hoc on Demand Distance Vector), a
reactive protocol which is also implemented in free space optical environment. We support our conclusions
that QDRP gains in terms of packet delivery percentage, end to end delay and goodput.
Congestion Control in Manets Using Hybrid Routing ProtocolIOSR Journals
Abstract : As the network size increases the probability of congestion occurrence at nodes increases. This is because of the event driven nature of ad hoc networks that leads to unpredictable network load. As a result congestion may occur at the nodes which receive more data than that can be forwarded and cause packet losses. In this paper we propose a hybrid scheme that attempts to avoid packet loss due to congestion as well as reduce end to end delay in delivering data packets by combining two protocols- Destination sequenced distance vector routing (DSDV), which is a table driven or proactive protocol and Improved Ad-hoc on demand vector routing (IAODV) which is an on-demand or reactive protocol that reduces packet loss due to congestion. The strategy adopted is use DSDV for path selection and if congestion occurs than switch over to IAODV. The routing performance of this model is then compared with IAODV and DSDV in terms of end to end delay, throughput and packet delivery fraction. Keywords- DSDV, Hybrid protocol, AODV, IAODV, MANET
Congestion Control in Manets Using Hybrid Routing ProtocolIOSR Journals
As the network size increases the probability of congestion occurrence at nodes increases. This is
because of the event driven nature of ad hoc networks that leads to unpredictable network load. As a result
congestion may occur at the nodes which receive more data than that can be forwarded and cause packet losses.
In this paper we propose a hybrid scheme that attempts to avoid packet loss due to congestion as well as reduce
end to end delay in delivering data packets by combining two protocols- Destination sequenced distance vector
routing (DSDV), which is a table driven or proactive protocol and Improved Ad-hoc on demand vector routing
(IAODV) which is an on-demand or reactive protocol that reduces packet loss due to congestion. The strategy
adopted is use DSDV for path selection and if congestion occurs than switch over to IAODV. The routing
performance of this model is then compared with IAODV and DSDV in terms of end to end delay, throughput
and packet delivery fraction
ENSURING QOS GUARANTEES IN A HYBRID OCS/OBS NETWORKijngnjournal
The bursting aggregation assembly in edge nodes is one of the key technologies in OBS (Optical Burst Switching) network, which has a direct impact on flow characteristics and packet loss rate. An optical burst assembly technique supporting QoS is presented through this paper, which can automatically adjust the threshold along with the increasing and decreasing volume of business, reduce the operational burst, and generate corresponding BDP (Burst Data Packet) and BCP (Burst Control Packet). In addition to the burst aggregation technique a packet recovery technique by restoration method is also described. The data packet loss due to the physical optical link failure is not currently included in the QoS descriptions. This link failure is also a severe problem which reduces the data throughput of the transmitter node. A mechanism for data recovery from this link failure is vital for guaranteeing the QoS demanded by each user. So this paper will also discusses a specific protocol for reducing the packet loss by utilizing the
features of both optical circuit switching (OCS) and Optical Burst switching (OBS) techniques
Determination of optimized sleep interval for 10 gigabit-passive optical net...IJECEIAES
The overall aim of this project is to investigate the application of a machine learning method in finding the optimized length of asleep time interval (TAS) in a cyclic sleep mechanism (CSM). Since past decade, the implementations of CSM in the optical network unit (ONU) to reduce the energy consumption in 10 gigabit-passive optical network (XG-PON) were extensively researched. However, the newest era sees the emergence of various network traffic with stringent demands that require further improvements on the TAS selection. Since conventional methods utilize complex algorithm, this paper presents the employment of an artificial neural network (ANN) to facilitate ONU to determine the optimized TAS values using learning from past experiences. Prior to simulation, theoretical analysis was done using the M/G/1 queueing system. The ANN was than trained and tested for the XGPON network for optimal TAS decisions. Results have shown that towards higher network load, a decreasing TAS trend was observed from both methods. A wider TAS range was recorded from the ANN network as compared to the theoretical values. Therefore, these findings will benefit the network operators to have a flexibility measure in determining the optimal TAS values at current network conditions.
Optical Burst Switching (OBS) is a data
switching technique for upcoming computer networks,
since this technique can perform data switching and
data processing operations with high speed and
efficiency. Its main goal is to get rid of problems found
in two main techniques, which are, Optical Circuit
Switching (OCS) and Optical Packet Switching (OPS).
Routing deflection methods route bursts to other output
ports, in fact it is not intended to resolve contention. In
OBS, when burst is not programmed on other output
port through routing deflection then it is simply deleted.
To route data to the receiver, the routing deflection does
not resolve all aspects that resulted loss of data;
therefore, the performance of schemes deflection
existence is not acceptable by the systems and so it
closes with deletion any plan to resolving contention,
backtrack if deflection fails (BDF), that is given as a
second opportunity to burst in order to face the failure
through deflection, the blocked bursts will return to the
previous station, to find suitable alternative available
paths.
History-based consistency algorithm for the trickle-timer with low-power and ...IJECEIAES
Recently, the internet of things (IoT) has become an important concept which has changed the vision of the Internet with the appearance of IPv6 over low power and lossy networks (6LoWPAN). However, these 6LoWPANs have many drawbacks because of the use of many devices with limited resources; therefore, suitable protocols such as the routing protocol for low power and lossy networks (RPL) were developed, and one of RPL's main components is the trickle timer algorithm, used to control and maintain the routing traffic frequency caused by a set of control messages. However, the trickle timer suffered from the short-listen problem which was handled by adding the listen-only period mechanism. This addition increased the delay in propagating transmissions and resolving the inconsistency in the network. However, to solve this problem we proposed the history based consistency algorithm (HBC), which eliminates the listen-only period based on the consistency period of the network. The proposed algorithm showed very good results. We measured the performance of HBC trickle in terms of convergence time; which was mainly affected, the power consumption and the packet delivery ratio (PDR). We made a comparison between the original trickle timer, the E-Trickle, the optimized trickle and our HBC trickle algorithm. The PDR and the power consumption showed in some cases better results under the HBC trickle compared to other trickle timers and in other cases the results were very close to the original trickle indicating the efficiency of the proposed trickle in choosing optimal routes when sending messages.
LOGIC OPTIMIZATION USING TECHNOLOGY INDEPENDENT MUX BASED ADDERS IN FPGAVLSICS Design
Adders form an almost obligatory component of every contemporary integrated circuit. The prerequisite of the adder is that it is primarily fast and secondarily efficient in terms of power consumption and chip area. Therefore, careful optimization of the adder is of the greatest importance. This optimization can be attained
in two levels; it can be circuit or logic optimization. In circuit optimization the size of transistors are manipulated, where as in logic optimization the Boolean equations are rearranged (or manipulated) to optimize speed, area and power consumption. This paper focuses the optimization of adder through technology independent mapping. The work presents 20 different logical construction of 1-bit adder cell in CMOS logic and its performance is analyzed in terms of transistor count, delay and power dissipation. These performance issues are analyzed through Tanner EDA with TSMC MOSIS 250nm technology. From this analysis the optimized equation is chosen to construct a full adder circuit in terms of multiplexer. This logic optimized multiplexer based adders are incorporated in selected existing adders like ripple carry
adder, carry look-ahead adder, carry skip adder, carry select adder, carry increment adder and carry save adder and its performance is analyzed in terms of area (slices used) and maximum combinational path delay as a function of size. The target FPGA device chosen for the implementation of these adders was Xilinx ISE 12.1 Spartan3E XC3S500-5FG320. Each adder type was implemented with bit sizes of: 8, 16, 32, 64 bits. This variety of sizes will provide with more insight about the performance of each adder in terms of area and delay as a function of size.
Delay Constrained Energy Efficient Data Transmission over WSNpaperpublications3
Abstract: In wireless sensor network generally concentrate on minimization of energy Consumption, Also reducing energy saving and end to end delay. Reduced the end to end delay is one of the main challenges in the Wireless Sensor Networks. In TDMA providing reliable packet transmission and two transmission scheduling schemes are used to maximize the end-end reliability within a delay bound in packet transmission called dedicated scheduling and shared scheduling. In addition, they formulate solutions for implementing two algorithms into two basic routing algorithms, single-path routing and any-path routing algorithm. The proposed system presented energy efficient sleep scheduling algorithm for reducing the energy for delay constrained in WLAN. This algorithm to maximize the energy saving for packet delay constraints and it determines sleep period and wake up time to be minimized, the aim of this project is proposed to maximize the length of sleep time under packet deadline constraints using green call algorithm. Keywords: Delay-constrained applications, energy efficiency, Sleep scheduling, wireless sensor network.
Title: Delay Constrained Energy Efficient Data Transmission over WSN
Author: H. Hasina Begaum
ISSN 2350-1022
International Journal of Recent Research in Mathematics Computer Science and Information Technology
Paper Publications
Fast Data Collection with Interference and Life Time in Tree Based Wireless S...IJMER
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
A STUDY OF QOS 6LOWPAN FOR THE INTERNET OF THINGSijscmcj
6LowPAN was introduced by the IETF as a standard protocol to interconnect tiny and constrained devices
across IPv6 clouds. 6LowPAN supports a QoS feature based on two priority bits. So far, little interest has
been granted and this QoS feature and there are no implementations of such feature in real networks. In
this paper,we evaluate the capacity to provide QoS of these priority bits in various scenarios. We show that
under very heavy or very low network load, these bits have a limited effect on the delay
10-Gb/S Transmission of Wdm Pon for Man with 50km Reach Based On FtthIJERA Editor
The wavelength-division-multiplexed passive optical network (WDM-PON) is considered to be the next evolutionary solution for a simplified and future-proofed access system that can accommodate exponential traffic growth and bandwidth-hungry new applications. WDM-PON mitigates the complicated time-sharing and power budget issues in time division- multiplexed PON (TDM-PON) by providing virtual point-to-point optical connectivity to multiple end users through a dedicated pair of wavelengths. The objective of this paper is proposed a scheme for metropolitan area networks comprising optical components based on arrayed waveguide grating multiplexers, demultiplexers .The Arrayed waveguide gratings based multiplexers and demultiplexers for WDM applications prove to be capable of precise multiplexing and demultiplexing of a large number of channels with relatively low losses.
Data collection algorithm for wireless sensor networks using collaborative mo...IJECEIAES
The simplest approach to reduce network latency for data gathering in wireless sensor networks (WSN) is to use multiple mobile elements rather than a single mobile sink. However, the most challneging issues faced this approach are firstly the high network cost as a result of using large number of mobile elements. Secondly, it suffers from the difficulty of network partitioning to achieve an efficient load balancing among these mobile elements. In this study, a collaborative data collection algorithm (CDCA) is developed. Simulation results presented in this paper demonstrated that with this algorithm the latency is significantly reduced at small number of mobile elements. Furthermore, the performance of CDCA algorithm is compared with the Area Splitting Algorithm (ASA). Consequently, the CDCA showed superior performance in terms of network latency, load balancing, and the required number of mobile elements.
Electrically small antennas: The art of miniaturizationEditor IJARCET
We are living in the technological era, were we preferred to have the portable devices rather than unmovable devices. We are isolating our self rom the wires and we are becoming the habitual of wireless world what makes the device portable? I guess physical dimensions (mechanical) of that particular device, but along with this the electrical dimension is of the device is also of great importance. Reducing the physical dimension of the antenna would result in the small antenna but not electrically small antenna. We have different definition for the electrically small antenna but the one which is most appropriate is, where k is the wave number and is equal to and a is the radius of the imaginary sphere circumscribing the maximum dimension of the antenna. As the present day electronic devices progress to diminish in size, technocrats have become increasingly concentrated on electrically small antenna (ESA) designs to reduce the size of the antenna in the overall electronics system. Researchers in many fields, including RF and Microwave, biomedical technology and national intelligence, can benefit from electrically small antennas as long as the performance of the designed ESA meets the system requirement.
Accelerate your Kubernetes clusters with Varnish CachingThijs Feryn
A presentation about the usage and availability of Varnish on Kubernetes. This talk explores the capabilities of Varnish caching and shows how to use the Varnish Helm chart to deploy it to Kubernetes.
This presentation was delivered at K8SUG Singapore. See https://feryn.eu/presentations/accelerate-your-kubernetes-clusters-with-varnish-caching-k8sug-singapore-28-2024 for more details.
Encryption in Microsoft 365 - ExpertsLive Netherlands 2024Albert Hoitingh
In this session I delve into the encryption technology used in Microsoft 365 and Microsoft Purview. Including the concepts of Customer Key and Double Key Encryption.
UiPath Test Automation using UiPath Test Suite series, part 3DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 3. In this session, we will cover desktop automation along with UI automation.
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UI automation Introduction,
UI automation Sample
Desktop automation flow
Pradeep Chinnala, Senior Consultant Automation Developer @WonderBotz and UiPath MVP
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
UiPath Test Automation using UiPath Test Suite series, part 4DianaGray10
Welcome to UiPath Test Automation using UiPath Test Suite series part 4. In this session, we will cover Test Manager overview along with SAP heatmap.
The UiPath Test Manager overview with SAP heatmap webinar offers a concise yet comprehensive exploration of the role of a Test Manager within SAP environments, coupled with the utilization of heatmaps for effective testing strategies.
Participants will gain insights into the responsibilities, challenges, and best practices associated with test management in SAP projects. Additionally, the webinar delves into the significance of heatmaps as a visual aid for identifying testing priorities, areas of risk, and resource allocation within SAP landscapes. Through this session, attendees can expect to enhance their understanding of test management principles while learning practical approaches to optimize testing processes in SAP environments using heatmap visualization techniques
What will you get from this session?
1. Insights into SAP testing best practices
2. Heatmap utilization for testing
3. Optimization of testing processes
4. Demo
Topics covered:
Execution from the test manager
Orchestrator execution result
Defect reporting
SAP heatmap example with demo
Speaker:
Deepak Rai, Automation Practice Lead, Boundaryless Group and UiPath MVP
Epistemic Interaction - tuning interfaces to provide information for AI supportAlan Dix
Paper presented at SYNERGY workshop at AVI 2024, Genoa, Italy. 3rd June 2024
https://alandix.com/academic/papers/synergy2024-epistemic/
As machine learning integrates deeper into human-computer interactions, the concept of epistemic interaction emerges, aiming to refine these interactions to enhance system adaptability. This approach encourages minor, intentional adjustments in user behaviour to enrich the data available for system learning. This paper introduces epistemic interaction within the context of human-system communication, illustrating how deliberate interaction design can improve system understanding and adaptation. Through concrete examples, we demonstrate the potential of epistemic interaction to significantly advance human-computer interaction by leveraging intuitive human communication strategies to inform system design and functionality, offering a novel pathway for enriching user-system engagements.
Essentials of Automations: Optimizing FME Workflows with ParametersSafe Software
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Join us for an insightful dive into the world of FME parameters, a critical element in optimizing workflow efficiency. This webinar marks the beginning of our three-part “Essentials of Automation” series. This first webinar is designed to equip you with the knowledge and skills to utilize parameters effectively: enhancing the flexibility, maintainability, and user control of your FME projects.
Here’s what you’ll gain:
- Essentials of FME Parameters: Understand the pivotal role of parameters, including Reader/Writer, Transformer, User, and FME Flow categories. Discover how they are the key to unlocking automation and optimization within your workflows.
- Practical Applications in FME Form: Delve into key user parameter types including choice, connections, and file URLs. Allow users to control how a workflow runs, making your workflows more reusable. Learn to import values and deliver the best user experience for your workflows while enhancing accuracy.
- Optimization Strategies in FME Flow: Explore the creation and strategic deployment of parameters in FME Flow, including the use of deployment and geometry parameters, to maximize workflow efficiency.
- Pro Tips for Success: Gain insights on parameterizing connections and leveraging new features like Conditional Visibility for clarity and simplicity.
We’ll wrap up with a glimpse into future webinars, followed by a Q&A session to address your specific questions surrounding this topic.
Don’t miss this opportunity to elevate your FME expertise and drive your projects to new heights of efficiency.
Neuro-symbolic is not enough, we need neuro-*semantic*Frank van Harmelen
Neuro-symbolic (NeSy) AI is on the rise. However, simply machine learning on just any symbolic structure is not sufficient to really harvest the gains of NeSy. These will only be gained when the symbolic structures have an actual semantics. I give an operational definition of semantics as “predictable inference”.
All of this illustrated with link prediction over knowledge graphs, but the argument is general.
Smart TV Buyer Insights Survey 2024 by 91mobiles.pdf91mobiles
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Builder.ai Founder Sachin Dev Duggal's Strategic Approach to Create an Innova...Ramesh Iyer
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The Art of the Pitch: WordPress Relationships and SalesLaura Byrne
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Elevating Tactical DDD Patterns Through Object CalisthenicsDorra BARTAGUIZ
After immersing yourself in the blue book and its red counterpart, attending DDD-focused conferences, and applying tactical patterns, you're left with a crucial question: How do I ensure my design is effective? Tactical patterns within Domain-Driven Design (DDD) serve as guiding principles for creating clear and manageable domain models. However, achieving success with these patterns requires additional guidance. Interestingly, we've observed that a set of constraints initially designed for training purposes remarkably aligns with effective pattern implementation, offering a more ‘mechanical’ approach. Let's explore together how Object Calisthenics can elevate the design of your tactical DDD patterns, offering concrete help for those venturing into DDD for the first time!
Key Trends Shaping the Future of Infrastructure.pdfCheryl Hung
Keynote at DIGIT West Expo, Glasgow on 29 May 2024.
Cheryl Hung, ochery.com
Sr Director, Infrastructure Ecosystem, Arm.
The key trends across hardware, cloud and open-source; exploring how these areas are likely to mature and develop over the short and long-term, and then considering how organisations can position themselves to adapt and thrive.
Key Trends Shaping the Future of Infrastructure.pdf
Volume 2-issue-6-1993-2004
1. ISSN: 2278 - 1323
International Journal of Advanced Research in Computer Engineering and Technology (IJARCET)
Volume 2, Issue 6, June 2013
www.ijarcet.org 1993
Throughput Maximization for Optical Burst
Switching Networks
Mrs. Kavitha.A Mrs. Helina Rajini J.
PG Student/Department of ECE Professor/ Department Of ECE
Sethu Institute of Technology, Kariapatti, India. Sethu Institute of Technology, Kariappatti, India.
Ph No: 9962730817 Ph No: 9486927217
Abstract- Optical burst switching is a one-way
reservation technique that provides connectionless
transmission services. In OBS Data Traffic
Discarded at immediate nodes is retransmitted by
the sources. In this project work an attempt is
made to improve the performance of Optical
Burst Switching (OBS) in situation where OBS
performance degrades when the control
processing time increases. Three feasible
methods to improve OBS performance without
significantly increasing the implementation
complexity. There are Addition of simple Fiber
Delay Lines (FDLs), Random Extra Offset time
and Window Based Channel Scheduling (WBS).
Additional FDLs can eliminate the negative
impact cause by the variation of the offset time
between control packets and data bursts. The
Random Extra Offset time approach does not
require any additional hardware and
computational complexity in the nodes. If higher
computational capability is available WBS in
general can provide better throughput
improvement than that of Random Extra Offset
time when FDLs are used in the nodes to
compensate the processing time.
Index Terms– Control overhead, Offset
time,Optical Burst Switching
I.INTRODUCTION
Recently, many in academic circles argued
that, due to the lack of sophisticated optical hardware
such as optical buffers, one-way reservation
techniques such as optical burst switching (OBS) are
likely candidates for the transmission of bursty traffic
in optical networks in the near future. OBS can
provide connectionless transmission services in
optical networks without sophisticated optical
hardware. Data traffic discarded at immediate nodes
is retransmitted by the sources. Thus the one-way
resource reservation of OBS effectively reduces the
hardware complexity and signal processing
requirement.
Since the duration of transmission for bursty
traffic is typically short, two-way or centralized
resource reservation approaches will be
inefficient if the data transmission time is not
much larger than the Propagation delay time
between nodes. The performance of a one-way
resource reservation scheme such as OBS, however,
is not sensitive to the propagation delay between
nodes.
Many approaches have been proposed to
improve the performance of OBS, for example,
adding optical buffers (switchable fiber delay lines)
2. ISSN: 2278 - 1323
International Journal of Advanced Research in Computer Engineering and Technology (IJARCET)
Volume 2, Issue 6, June 2013
www.ijarcet.org 1994
to OBS nodes, burst segmentation, centralized
resource reservation, and dynamic routing. However,
many of these proposals are not practical because
they inevitably require much more sophisticated
implementation than the original OBS scheme. In
order to improve OBS performance without
significantly increasing the implementation
complexity, it is necessary to delineate the
relationship among control processing time, one-way
resource reservation, and OBS such that the merits of
different improvement approaches can be fully
understood. With this understanding, different
performance improvement methods can be combined
to further improve the OBS performance.
Our main contributions include the following:
1) The performance model has been derived to
explain the phenomenon of OBS throughput
degradation when the control packet processing time
Tcp increases.
2) The compensation factor β in the fiber delay
line (FDL) overcompensation approach is critical to
OBS performance improvement, but the proper value
of β is not easy to determine. We propose to use
FDLs only for Tcp compensation. Further
improvement in OBS performance is to be achieved
by other methods.
3) The performance improvement mechanism
of the random extra offset time approach can also
improve system performance even if the OBS has
zero Tcp or Tcp is fully compensated by FDLs.
4) The first window-based channel scheduling
(WBS) that is suitable for OBS with both window
time Twd and Tcp compensated by FDLs. In
traditional WBS, only Twd is compensated. The
proposed WBS can provide better performance
improvement for OBS, with and without FDL
compensation, than that of traditional WBS.
5) The performance of OBS can be
significantly improved by combining different
methods such as FDL compensation plus random
extra offset time and FDL compensation plus WBS.
II. RELATED WORK
For improving the optical network performance and
achieving the QOS parameters we definitely improve
the performance of throughput in the networks.
The Author in [1] has proposed the
performance model of optical burst switching (OBS)
that can explain the degradation of OBS throughput
performance when the control packet processing time
increases was developed. To improve OBS
performance without significantly increasing the
implementation complexity three methods was
employed: addition of simple fiber delay lines
(FDLs), random extra offset time, and window-based
channel scheduling (WBS).
The Authors in [12] has proposed the
method based on Just-Enough-Time (JET), is
described, along with the applicability of OBS
protocols to IP over WDM. Specific issues such as
the use of fiber delay lines (FDL) for accommodating
processing delay and/or resolving conflicts are also
discussed. JET-based OBS protocols can achieve
good bandwidth utilization by using delayed
reservation, and improve fairness by assigning an
additional offset time (which is equivalent to a higher
priority) to bursts travelling through more hops. OBS
can be used to efficiently support multicasting at the
optical layer to take advantage of the inherent
multicasting capability of some optical switches as
well as the knowledge of the physical topology of the
WDM layer.
The Authors in [18] has proposed the JIT-
OBS paradigm is designed for ultra-low-latency
unidirectional transport of data-bursts across an
optical network. Just-Enough-Time (JET) is the
another signaling scheme, which attempts to utilize
additional knowledge concerning the duration of
burst transmission in order to schedule the cross-
connect settings in each intermediate switches. Due
to the reduced channel hold time made possible by
forward scheduling, JET may deliver better resource
utilization than JIT Signal scheme.
The Authors in [15] has proposed the Burst
segmentation is the process of dropping only those
parts of a burst which overlap with another burst.
Burst assembly is the process of aggregating and
assembling IP packets into a burst at the edge of the
network. The most common burst-assembly
approaches are timer-based and threshold-based An
3. ISSN: 2278 - 1323
International Journal of Advanced Research in Computer Engineering and Technology (IJARCET)
Volume 2, Issue 6, June 2013
www.ijarcet.org 1995
analytical model for prioritized burst segmentation
was developed to calculate the packet loss
probabilities for a two-priority network. The high-
priority bursts have significantly lower losses and
delay then the low-priority bursts. And also the
concept of composite burst assembly to handle the
differentiated service requirements of the IP packets
at edge nodes of the optical burst-switched network
was described. We considered four different burst
assembly approaches and evaluated their
performance in terms of loss. But combination of
these methods will increase the overall transmission
delay.
The Authors in [10] has proposed the
analytical model was introduced to evaluate the
performance of optical burst switch (OBS)
architectures employing fiber delay lines (FDLs) as
optical buffers to reduce burst-loss probability. In
OBS, a fundamental problem is how to handle burst
contentions that occur when two or more incoming
bursts are directed simultaneously to a common
output line. Two basic contention resolution
approaches that have been considered involve the use
of multiple wavelengths and/or fiber delay lines
(FDLs). There are some limitations in this method.
An FDL can only provide a deterministic delay to an
incoming burst. Moreover, the burst must be dropped
if the maximum delay provided by the FDL is not
sufficient. And also the complexity of the Analytical
model makes it infeasible for solving problems of
practical interest.
The Authors in [7] has proposed the method
for the increasing bandwidth demands and reduce
costs, Optical Burst Switching paradigm was
proposed. The performance of a large set of
scheduling algorithms, called best-effort online
scheduling algorithms, for OBS networks was
analyzed and number of interesting upper and lower
bounds on the performance of such algorithms was
established. Our analysis shows that the performance
of any best-effort online algorithm is closely related
to a few factors, such as the range of offset time,
burst length ratio, scheduling algorithm, and number
of data channels. Consider a large set of scheduling
algorithms, called best effort online scheduling
algorithms, which includes most of the well-known
burst scheduling algorithms such as Latest Available
Unused Channel with Void Filling (LAUC-VF), First
Fit with Void Filling and Round Robin with Void
Filling algorithm.
SWITCHING TECHNIQUES FOR
OPTICAL NETWORKS:
Three switching techniques that are well
studied to carry IP traffic over WDM networks are
optical circuit switching, optical packet switching and
optical burst switching.
A. Optical Circuit Switching:
In Optical Circuit Switching (OCS), the
network is configured to establish circuits, from an
entry to an exit node, by adjusting the optical cross
connect circuits in the core routers in a manner that
the data signal, in an optical form, can travel in an
all-optical manner from the entry to the exit node.
This approach suffers from all the disadvantages
known to circuit switching - the circuits require time
to set up and destroy, and while the circuit is
established, there sources will not be efficiently used
to the unpredictable nature of traffic.
B. Optical Packet Switching:
In Optical packet switching is suitable for
supporting bursty traffic since it allows statistical
sharing of the channel bandwidth among packets
belonging to different source and destination pairs. In
optical packet switching, the payload (i.e. data) will
remain in the optic form, while its header may be
processed electronically or optically. In packet
switching, in order to facilitate implementation,
headers can be transmitted on a separate wavelength
or a subcarrier channel. Specifically, using a separate
control wavelength or subcarrier channel makes it
possible for a node to process the header (and set the
local switch) before the payload is fully stored (in
FDLs). In packet switched networks, IP traffic is
processed at every router on a packet by packet basis.
So, it takes more transmission time. To overcome this
limitation, we go for optical burst switching (OBS).
C. OPTICAL BURST SWITCHING
In Optical burst switching (OBS) is the new
switching technique for next generation optical
networks. OBS combines the advantages of both
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circuit and packet switching while overcoming their
limitations. In optical burst switching, the term burst
is a variable length data packet, assembled at an edge
router by aggregating a number of IP packets, which
may be received from a single host or from multiple
hosts belonging to the same or different access
networks. A burst has two components: control and
payload. The control packet carries the header
information. Thus, the control component incurs an
overhead, referred to as control overhead. Payload is
the actual data transmitted. Control packet is sent first
followed by the payload on a separate wavelength
channel after an offset time equal to the processing
time of control packet at intermediate node. Control
packet is processed electronically at each
intermediate node and reserves resources for a period
starting from the time the payload/data burst is
expected to arrive at the node until the transmission is
completed.
A one-way reservation scheme is used to
reserve wavelength channels dynamically for the DB
on a link-by-link basis. If reservation is successful the
control packet is transmitted to the next node on the
path, else it is dropped at the node. For a successful
reservation, switches are configured by the time
payload/data burst arrive at the node. Hence the data
burst remains in optical domain from source to
destination.
Switching
Techniques
Circuit Packet OBS
Bandwidth
utilization
Low High High
Latency High Low Low
Optical
Buffering
Not
Required
Required Not
Required
Overhead Low High High
Adaptively Low High High
Table 2.1 Comparison of various switching
techniques
ARCHITECTURE OF OBS:
Architecture of OBS network is shown in
Figure 2.1. OBS network consists of two types of
nodes: edge node and core node. Edge nodes are at
the interface between electronic and optical domain.
Edge nodes can be an ingress or egress node. Packets
are assembled into bursts at ingress edge node, which
are then routed through the OBS network and
disassembled back into packets at egress edge node.
A core node is mainly composed of an optical
switching matrix and a switch control unit which are
responsible to forward data burst.
Figure 2.1 Architecture of OBS
A node in OBS network consists of both
optical and electronic components. The optical
components are multiplexers (Mux), demultiplexers
(Demux) and an optical switching network (OSN).
The electronic components are input modules (IM),
output module (OM), a control burst router (CBRT),
and a scheduler. An optical burst switch control unit
transfers an incoming data burst from an input port to
its destination output port. When an edge node
intends to transmit a data burst, it sends a control
packet on the control wavelength to a core node. At
core node, the control packet on the control channel
is input to the corresponding IM, which converts the
control packet into electronic form. The control fields
are extracted from the control packet. The CBRT
uses these control fields to determine the next
outgoing fiber for the corresponding payload by
consulting a routing table maintained locally. The
control packet is scheduled for transmission onto the
selected outgoing link by the scheduler and the
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control packet is buffered until the scheduled time.
The scheduler maintains a control packet queue. The
scheduler also reserves wavelength on the determined
links for the upcoming payload. The control packet is
then forwarded on the OM, which updates its control
fields and transmits it to the selected outgoing fiber
using the optical transmitter. Just before the payload
arrives, the switching element in the node is
configured to connect the input port to the
corresponding output port for the entire duration of
the burst transmission. If the control packet is unable
to reserve the wavelength then the control packet as
well as payload is dropped.
III. OBJECTIVES AND OVERVIEW
OF THE PROPOSED MECHANISM
APPROACHES TO IMPROVE THE OBS
THROUGHPUT
In spite of the importance of higher
throughput, any throughput improvement methods
should not require network wide signaling or
sophisticated optical hardware. The required
computations for resource reservation should also
increase only moderately. With these constraints, a
single method is usually insufficient to provide the
required throughput improvement. By combining
methods that are based on different solution
strategies, it may be possible to improve the OBS
throughput performance without significantly
increasing the OBS implementation complexity if all
these methods require low additional implementation
overhead. The three feasible methods include adding
FDLs, random extra offset time, and window-based
channel scheduling. We investigate the nature of each
method and how they improve the throughput
performance.
A.FIBER DELAY LINE METHOD:
We know that data bursts with different
values of H will have the same probability to block
each other if the offset time Toff is a constant. Under
such conditions, we can eliminate the transmission
bandwidth wastage caused by the offset time priority
effect. Thus we should install FDLs at the node
inputs to delay the incoming data bursts’ Tcp time. It
has been reported in that JET OBS will have better
performance if the same numbers of FDLs are used
as optical buffer like FDL delay units in JET OBS.
The implementation of optical buffers to date,
however, is still difficult. In contrast, only a single
simple FDL (as shown in Fig.2.2) is required per
node input to compensate the Tcp of all incoming
data bursts in all wavelength channels. It may not be
easy to use FDLs to exactly compensate the control
packet processing time Tcp because Tcp can vary
with the system loading and nodes. We observe that
one solution is to set the delay time TFDL of FDLs to
the maximum of Tcp and delay the forwarding of the
control packet to the next node, if necessary, to keep
the offset time Toff to be a constant. When the offset
time Toff is constant, data bursts with different path
lengths will have the same channel reservation
success probability at an intermediate node.
Therefore, data bursts with larger hop count paths
will suffer from larger loss rate. We observe that the
solution requiring minimum extra effort is to
overcompensate the control packet processing time
by setting the length of the FDLs to slightly larger
than that required for the compensation of Tcp. We
define , where β ≥ - Tcp is the compensation factor.
The cases of β < 0 and β > 0 respectively represent
when FDLs under compensate and overcompensate
the control packet processing time Tcp.
Figure 3.1 An OBS node with FDLs
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Under compensation of Tcp will surely
degrade OBS system performance, whereas
overcompensation can often improve the throughput
performance. Overcompensation of Tcp will increase
the offset time between the control packet and the
data burst when they pass the nodes along the path.
Data bursts that have passed more nodes will
therefore have a greater chance to reserve an output
channel at an intermediate node because of the larger
offset time. Though β is critical to the system
performance, the proper value of β is not easy to
determine because it varies with network topology
and traffic. From implementation consideration, it
may be better to first use FDLs to compensate the
control packet processing time Tcp and then use
other methods to further improve the throughput
performance.
B.RANDOM EXTRA OFFSET TIME:
Throughput improvement has been observed
with an extra random offset time and this is attributed
to the traffic shaping effect of the data bursts at OBS
source nodes. However, we find that the random
extra offset time also significantly weakens the
connection between the number of hops to
destination H and the offset time, and hence reduces
blocking. We observe that random extra offset time
can further improve the throughput performance even
if the offset time priority effect of OBS is reduced by
FDL compensation. Random extra offset time can
reduce the loss rate of data bursts with large hop
count paths and improve the throughput performance.
We first consider the cases of OBS without
control packet processing time compensation. When
a random extra offset time is added to Eq. (4.4), the
offset time becomes
Where Tex is the random extra offset time. The
difference of the two offset times Tfx and Tf1 is
Where Tdiff is the difference between the two
random extra offset times.
Figure 3.2 A network with one k-hop path & k one-
hop path
For the performance of OBS with FDL
compensation being improved by random extra offset
time, we use a simplified model to illustrate the
principle. Figure 5.2 shows an OBS network with
constant offset time. There is one k-hop path (P0) and
k one-hop paths (P1 to Pk).Without the random extra
offset time, all data bursts have the same channel
reservation success probability s at any node, e.g., s =
0.5. The average loss rate of a P0 data burst will
therefore be, and that of Pj is, for 1 ≤ j ≤ k. After an
extra offset time Tex has been randomly
added/subtracted to/from each pair of control packet
and data burst of P0, we assume that the channel
reservation success probability of a data burst will
become one of the two values s - sex and s + sex at
random, where sex (≤ s) is a random reservation
probability caused by Tex. We assume sex to be a
constant for ease of illustration. Although the average
channel reservation success probability of a data
burst is still s, the average loss rate of P0 and Pj
become
For 1 ≤ j ≤ k.
Data bursts with larger hop count paths will
have higher loss rate. The reduction of loss of data
bursts with larger hop count paths is achieved at the
expense of the increase of loss of data bursts with
smaller hop count paths. Similar to the case of FDL
overcompensation, larger values of random extra
offset time Tex do not guarantee increased system
throughput. However, JET OBS can have throughput
improvement with a large range of Tex and the
selection of a suitable value of Tex becomes easy.
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C.WINDOW BASED CHANNEL SCHEDULING:
Window-based channel scheduling schemes
delay the channel routing assignment an additional
Twd time after reading the information of a control
packet. It enables us to predict the impact of a
channel assignment to the channel requests (control
packets) arriving in the future Twd time interval. We
can therefore make better channel/routing assignment
decisions than the FCFS approach. To illustrate,
Fig.2.3 shows four control packets and their
associated data bursts arriving at a node. Assuming
that all data bursts are routed to the same output port
Ox of the node, we may need three output channels if
the channel assignment uses FCFS according to the
arrival of control packets, e.g.,
and
and where Oxy is the yth channel
of output port Ox. With the additional Twd delay
time; however, we need to use only two for the
channel assignment, e.g.
and .
Figure 3.3 Transmission of data bursts in OBS
There are two major concerns with WBS
OBS schemes. First, the additional Twd time delay of
the control packet in OBS will increase the
equivalent control packet processing time to Tcp +
Twd. Note that a normal JET system with control
packet processing time Tcp + Twd will have larger
blocking probability than that with control packet
processing time Tcp unless Tcp is much larger than
the average data burst transmission time L. Similarly,
a WBS OBS scheme can have even lower throughput
if Tcp is not much larger than L. Therefore, for the
WBS OBS schemes, we can assume that Tcp is much
larger than L or the Twd delay time is compensated.
WBS OBS assuming large Tcp does not require any
additional hardware and only needs to extend the
initial offset time at the source.
Since the value of Tcp should not be
restricted, delay compensation seems to be a more
attractive approach. At the moment, adding FDLs at
the node inputs is the only practical way to
compensate the delay of the control packet in a node.
We believe that adding FDLs only for Twd
compensation is not reasonable. Hence, unlike
traditional WBS schemes, we assume that WBS OBS
with FDLs for delay compensation will always have
constant offset time between control packets and data
bursts, i.e., both Twd and Tcp are compensated.
Next, it is necessary to determine the
procedure for assigning the output channel to a
control packet, say CPx, after the Twd time delay. A
common approach is to virtually assign output
channels to CPx and other control packets that have
arrived in the Twd time period according to the
arrival sequence of their associated data bursts. The
data burst DBx of CPx will get the channel that is
assigned to DBx in the virtual channel assignment.
DBx will be rejected if it fails to get a channel in the
virtual channel assignment. This approach is
effective, e.g., we will need only two output channels
in Fig.2.3. However, it assumes no compensation for
the control packet processing time Tcp and only the
window time Twd is compensated. It will not be
useful if both Tcp and Twd are compensated, i.e., no
further throughput improvement can be obtained. In
such a situation, the data burst arrival sequence is the
same as that of the control packets. We need a WBS
OBS channel assignment procedure for all
circumstances. We propose to use a basic principle:
reject a data burst if it will cause the blocking of
subsequent data bursts and decrease the system
throughput. Thus we assign the output channel based
on the impact of the control packet on other control
packets (their associated data bursts) arriving in the
Twd delay time interval. Consequently, we weigh the
data burst DBk of a control packet CPk with a value
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wk. To assign a channel to a control packet CPx (data
burst DBx), we first compute two control packet sets
S and R, where S(R) is the set of control packets that
arrive in the Twd delay time interval and their
associated data bursts will be accepted if DBx has
(has not) been assigned a channel. The latest
available unused channel with the void filling
(LAUC-VF) scheme is used in Fig 5.3. assuming two
output channels Ox,1 and Ox,2 only, we will have
S={CP2(DB2 Ox,1),CP3(DB3 Ox,2)} and R
={CP2(DB2 Ox,1),CP3(DB3 Ox,2),CP4(DB4
Ox,1)} according to the arrival sequence of CP2,
CP3, and CP4. LAUC-VF chooses the idle time gap
in the channels. The weighing of the data burst is
important for WBS OBS performance.
We have tested the wx setting of (1) a
nonzero constant c; (2) the data burst length Lx; (3)
the number of passed hops from source hx. This
simple wx setting provides slightly better system
throughput performance than that from the common
approach of channel assignment when WBS OBS is
without FDL compensation. Note that the common
channel assignment procedure approach does not
improve the throughput of WBS OBS with FDL
compensation.
The table represents the average value of the
computational time of our methods oriented active
appearance model and integrated graph cut oriented
active appearance model will be implemented and
calculated the results as early as possible. However,
the proposed channel assignment procedure can
further improve the system throughput in such cases.
Proposed Burst Delay Feedback Scheduling
Algorithm
Our aim is to schedule as many bursts as
possible with reduced burst loss. Therefore we
propose a new Burst scheduling algorithm named
Burst Delay Feedback Scheduler for scheduling the
burst with minimum loss. In a feedback-based
network, the ingress nodes have knowledge of the
network state and they can respond to changes in the
network load. This mechanism support quality of
service (QoS) for different class of bursts. In
feedback scheduling the core node senses the data
traffic and sends feedback to the previous core/edge
node for delay the incoming burst in order to
minimize contention. This feedback contains
information that how much time the data burst must
delayed to reduce contention.
Performance parameters for each burst flow
are exchanged by a feedback message to the ingress
nodes. According to the information contained in the
message, the edge nodes dynamically adjust its
parameters needed to achieve a defined QoS
parameter such as bandwidth, throughput and delay.
The adjusted parameters are the offset time parameter
or the burstification rate. Feedback control approach
computes accurate burstification rate (i.e., rate by
which the bursts are injected into the network) for
each class of bursts. Based on the computed
burstification rates, the maximum delay is calculated
and guaranteed to the deterministic level.
Figure 3.4. A linear control system with
feedback control mechanism using burst delay
feedback scheduler.
General diagram for a linear control system
implementing closed loop feedback control
mechanism is shown in Fig. 3. At first edge node
generates bursts by aggregating a number of IP
packets directed towards the same core node. The
burst manager controller (BMC) controls the
Burstification rate which resides at every edge node
of the network. Every core node sends a feedback to
the edge nodes containing a reduction request of the
burstification rate. The reference Delay is a reference
value that the controlled output parameter should be
restrained in the network. The error is the difference
between the reference Delay and the measured Delay.
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The burst manager controller (BMC) takes the error
value as an input and generates a burstification rate
accordingly based on a control law. This approach
guarantees quality of service in terms of throughput
and latency for each class of burst.
IV.PERFORMANCE EVALUATION
We use simulations to verify the throughput
and transmission delay using the combinations of the
methods discussed in Section III and IV on a 22-node
23-link NS2 topology network. We assume that all
links are bidirectional. In the simulations, we assume
that data bursts arriving at the nodes follow the
Poisson process. When a new data burst arrives at a
node, it randomly chooses a destination from the rest
of the nodes in the network and uses shortest-path
routing to determine the path. The maximum number
of paths per link for the NS2 is 23. Therefore, the
maximum throughput per node is 13/23 or around
0.565. This value is our maximum achievable
throughput.
The node creation in OBS network and the NAM
window is shown below
Figure 4.1 NAM output showing Node Creation in
OBS Network
Figure 4.2 Creation of OBS Nodes
Figure 4.3 Data Burst Transmission between
Nodes
In the above diagram 4.3 shows the OBS
network is created and Data Burst is transmitted
between the nodes. The coloured line indicates that
burst transmission between different nodes.
Once a new data burst arrives at a node, a
control packet is sent out immediately to reserve the
required channels and resources on the path. The data
burst is then transmitted after the offset time Toff
according to one of the settings (a) Tcp + Tex, and
(b) Tcp + Twd. Setting (a) is for OBS that also uses
the random extra offset time approach, whereas
setting (b) is for those that also use window-based
channel scheduling. In the simulations, we assume
negligible switch reconfiguration time in the OBS
node (Tsw = 0). The traffic loading to a node is the
number of data burst arrivals to the node per unit
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time divided by the number of wavelength channels
per link.
Throughput Performance of BDFS with
WBS and FDL compensation
In the existing Window Based Channel
Scheduling with FDLs for control packet processing
time overcompensation, throughput performance was
improved. To further improve the throughput and
reduce delay, we may combine WBS plus FDL
overcompensation with Burst Delay Feedback
Scheduling.
Figure 4.4 Throughput Maximization
graph
The Throughput curves on NS2 with Tcp = 1 using WBS and FDL
compensation with Burst Delay Feedback Scheduling.
The traffic load-throughput performance of
OBS with WBS of Twd = 1 plus FDL compensation
of W2
Delay Performance of Burst Scheduling with WBS
and FDL compensation
By combining BDFS and WBS with FDL
compensation, reduced transmission delay was also
achieved
.
Figure 4.5 Traffic Load vs. Delay
The Transmission Delay curves on NS2 with Tcp = 1
using WBS and FDL compensation with BDFS.
Figure 4.4 is the traffic load-throughput
performance of OBS with WBS of Twd = 1 plus FDL
compensation of TFDL = 2.0 with and without
proposed burst scheduling, when Tcp = 1. From the
simulation results, the Delay reached nearly 1ms only
when full load condition, in the Burst scheduling with
WBS OBS plus FDL compensation (blue line)
method. But, in the WBS OBS plus FDL
compensation without BS (green line) method delay
reached 1ms for 0.9 traffic load itself. So the
proposed method can decrease the OBS delay.
Figure 4.6 Offset Time vs. Throughput
Measurement of Average Loss Rate and Burst Size
using Burst Feedback Scheduling:
Figure below shows, average loss rate
performance of OBS by using burst delay feedback
scheduling. When delay time is varied from 0.2 to 1,
the average loss rate of the Burst scheduling is
varied. When compared to window based channel
scheduling with FDL, the performance of burst
scheduling was improved. From the figure average
loss rate vary from 0.11 to 0.13.
Figure 4.7 Delay time Vs Average loss rate.
Similarly figure shows burst size of OBS for various
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simulation times.
Measurement of Traffic Load and Burst Loss Rate
Using Burst Feedback Scheduling:
Figure 4.8 Traffic Load vs. BurstLosssRate
MEASUREMENT OF TRAFFIC LOAD VS
THROUGHPUT USING BURST FEEDBACK
SCHEDULING ALGORITHM
Figure 4.9 Traffic Load vs. Throughput
V.CONCLUSION
This paper proposes the method to improve the
OBS performance without increasing the
implementation complexity. By combining three
methods that are based on different principles, OBS
performance can be improved: adding simple FDLs,
random extra offset time, and WBS. In some cases
(two data bursts having same offset value), Window
Based Channel Scheduling will reject a data burst if it
will cause the blocking of subsequent data bursts and
will decrease the system throughput. So, we have to
assign the output channel based on the impact of the
control packet on other control packets (their
associated data bursts) arriving in the Twd delay time
interval. For this purpose, we can use Burst
scheduling algorithm in addition with those existing
methods. Thus it will increase overall system
throughput.
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Authors Profile
A.Kavitha received her B.E
degree in Electronics and Communication
Engineering from Arignar Anna Institute of Science
and Technology,
Sriperumbudur,
Kanchipuram Dist.,
Tamilnadu, India.
Currently she is
pursuing her M.E
(Communication
Systems) from Sethu
Institute of
Technology,
Kariapatti, Virudhunagar Dist, and Tamilnadu, India.
Her research interests are Optical Networks, Optical
Burst Switching Networks and Wireless Networks.
Helina Rajini.J received her
B.E Electronics and
Communication Engineering
from Thiagarajar College of
Engineering, Madurai and
M.E (Applied Electronics)
from Government
College of Technology, Coimbatore in the year 1989 and
1991 respectively. She is currently pursuing her Ph.D from
Anna University, Chennai. She is presently working as
professor in Department of Electronics and Communication
Engineering at Sethu Institute of Technology, India. She
has published many research papers in the National and
International Conferences and journals. Her research
interests include Optical Burst Switching Networks,
Passive Optical Networks and WDM optical networks