The explicit rate flow control mechanisms for ABR service are used to sharethe available bandwidth of a bottleneck link fairly and reasonably among many competitive users andto maintain the buffer queue length of a bo...The explicit rate flow control mechanisms for ABR service are used to sharethe available bandwidth of a bottleneck link fairly and reasonably among many competitive users andto maintain the buffer queue length of a bottleneck switch connected to the link at a desired levelin order to avoid and control congestion in ATM networks. However, designing effective flow controlmechanisms for the service is known to be difficult because of the variety of dynamic parametersinvolved such as available link bandwidth, burst of the traffic, the distances between ABR sourcesand switches. In this paper, we present a fuzzy explicit rate flow control mechanism for ABRservice. The mechanism has a simple structure and is robust in the sense that the mechanism'sstability is not sensitive to the change in the number of active virtual connections (VCs). Manysimulations show that this mechanism can not only effectively avoid network congestion, but alsoensure fair share of the bandwidth for all active VCs regardless of the number of hops theytraverse. Additionally, it has the advantages of fast convergence, low oscillation, and high linkbandwidth utilization.展开更多
One of the more challenging and unresolved issues in ATM networks is the congestion control of available bit rate (ABR). The dynamic controller is designed based on the control theory and the feedback mechanism of e...One of the more challenging and unresolved issues in ATM networks is the congestion control of available bit rate (ABR). The dynamic controller is designed based on the control theory and the feedback mechanism of explicit rates With the given method of a chosen parameter, it can guarantee the stability of the controller and closed loop system with propagation delay and bandwidth oscillation. It needs less parameters(only one) to be designed. The queue length can converge to the given value in the least steps. The fairness of different connections is considered further. The simulations show better performance and good quality of service(QoS) is achieved.展开更多
For the Asynchronous Transfer Mode (ATM) networks with time-varying multiple time-delays, a more realistic model for the available bit rate (ABR) traffic class with explicit rate feedback is introduced. A fuzzy-im...For the Asynchronous Transfer Mode (ATM) networks with time-varying multiple time-delays, a more realistic model for the available bit rate (ABR) traffic class with explicit rate feedback is introduced. A fuzzy-immune controller is designed, which can adjust the rates of ABR on-line, overcome the bad effect caused by the saturation nonlinearity and satisfy the weighted fairness. Also, the sufficient condition that guarantees the stability of the closed-loop system with a fuzzy-immune controller is presented in theory for the first time. The algorithm exhibits good performance, and most importantly, has a solid theoretical foundation and can be implemented in practice easily. Simulation results show that the control system is rapid, adaptive, robust, and meanwhile, the quality of service (QoS) is guaranteed.展开更多
A binary available bit rate (ABR) scheme based on discrete-time variable structure control (DVSC) theory is proposed to solve the problem of asynchronous transfer mode (ATM) networks congestion in this paper. A ...A binary available bit rate (ABR) scheme based on discrete-time variable structure control (DVSC) theory is proposed to solve the problem of asynchronous transfer mode (ATM) networks congestion in this paper. A discrete-time system model with uncertainty is introduced to depict the time-varying ATM networks. Based on the system model, an asymptotically stable sliding surface is designed by linear matrix inequality (LMI). In addition, a novel discrete-time reaching law that can obviously reduce chatter is also put forward. The proposed discrete-time variable structure controller can effectively constrain the oscillation of allowed cell rate (ACR) and the queue length in a router. Moreover, the controller is self-adaptive against the uncertainty in the system. Simulations are done in different scenarios. The results demonstrate that the controller has better stability and robustness than the traditional binary flow controller, so it is good for adequately exerting the simplicity of binary flow control mechanisms.展开更多
A new ant-algorithm-based routing approach is proposed for the VC routing problem with considering the comprehensive effect between the resource utilization and the load balance in ATM networks. In the approach, the b...A new ant-algorithm-based routing approach is proposed for the VC routing problem with considering the comprehensive effect between the resource utilization and the load balance in ATM networks. In the approach, the backup paths are calculated first, and then an ant algorithm based on the ability of ants to find the shortest path between their nest and the food source during their searching food, is constructed to optimize the VC global route. Simulation results show that the proposed approach can realize VC routing effectively according to the current traffic states in the networks and the user-specified delay requirements.展开更多
A new neural network based method for solving the problem of congestion control arising at the user network interface (UNI) of ATM networks is proposed in this paper. Unlike the previous methods where the coding rate ...A new neural network based method for solving the problem of congestion control arising at the user network interface (UNI) of ATM networks is proposed in this paper. Unlike the previous methods where the coding rate for all traffic sources as controller output signals is tuned in a body, the proposed method adjusts the coding rate for only a part of the traffic sources while the remainder sources send the cells in the previous coding rate in case of occurrence of congestion. The controller output signals include the source coding rate and the percentage of the sources that send cells at the corresponding coding rate. The control methods not only minimize the cell loss rate but also guarantee the quality of information (such as voice sources) fed into the multiplexer buffer. Simulations with 150 ADPCM voice sources fed into the multiplexer buffer showed that the proposed methods have advantage over the previous methods in the aspect of the performance indices such as cell loss rate (CLR) and voice quality.展开更多
In this paper, an extended Kendall model for the priority scheduling input-line group output with multi-channel in Asynchronous Transfer Mode (ATM) exchange system is proposed and then the mean method is used to mod...In this paper, an extended Kendall model for the priority scheduling input-line group output with multi-channel in Asynchronous Transfer Mode (ATM) exchange system is proposed and then the mean method is used to model mathematically the non-typical non-anticipative PRiority service (PR) model. Compared with the typical and non-anticipative PR model, it expresses the characteristics of the priority scheduling input-line group output with multi-channel in ATM exchange system. The simulation experiment shows that this model can improve the HOL block and the performance of input-queued ATM switch network dramatically. This model has a better developing prospect in ATM exchange system.展开更多
The single bottleneck node of ATM networks is considered. The virtual queue mechanism and the method of proportion-integral-differential(PID) control are adopted in the congestion control. The sufficient condition of ...The single bottleneck node of ATM networks is considered. The virtual queue mechanism and the method of proportion-integral-differential(PID) control are adopted in the congestion control. The sufficient condition of the considered system’s stability is given. The method of determining the PID parameters is given further. To quicken the speed of startup and remove the congestion rapidly, the factors of increase and decrease are set according to the length of queue. The result of simulation shows that the system, given an appropriate group of parameters, can acquire good robustness and dynamic performance, and guarantees the quality of service at the same time.展开更多
Aim To Put forward an improve algorithm for real-time connection admission control (CAC) decision. Methods converted equations of Cell loss ratio (CLR) upper bound were derived based on typical approaches to reduce co...Aim To Put forward an improve algorithm for real-time connection admission control (CAC) decision. Methods converted equations of Cell loss ratio (CLR) upper bound were derived based on typical approaches to reduce computing load. Moreover, the effects of usage parameter control (UPC) policing and bandwidth allocation functions were combined to deduce improver equations. computing load and admission region of the new algorithm were analyzed, while numerical examples and comparisons with classical non-parametic method were also included. Results Computing burden was reduced. More accurate estimation of CLR was obtained. The admission region of new algorithm was larger than typical non-parametric approach and was variable according to the burst length.Conclusion The calculation burden of new algorithm for CLR estimation is lighter than classical non-parametric approach. In addition to that, just as many information as what we can get in connection setup process are used for CAC decision. So it is not only a practicable but also an effective method that can be used in real-time processing.展开更多
To enhance the fidelity and accuracy of the simulation of communication networks,hardware-in-the-loop(HITL) simulation was employed.HITL simulation methods was classified into three categories,of which the merits an...To enhance the fidelity and accuracy of the simulation of communication networks,hardware-in-the-loop(HITL) simulation was employed.HITL simulation methods was classified into three categories,of which the merits and shortages were compared.Combing system-in-the-loop(SITL) simulation principle with high level architecture(HLA),an HITL simulation model of asynchronous transfer mode(ATM) network was constructed.The throughput and end-to-end delay of all-digital simulation and HITL simulation was analyzed,which showed that HITL simulation was more reliable and effectively improved the simulation credibility of communication network.Meanwhile,HLA-SITL method was fast and easy to achieve and low-cost during design lifecycle.Thus,it was a feasible way to research and analyze the large-scale network.展开更多
A fuzzy requirement based strategy for QoS service in broadband networks was presented. With the analysis of QoS service in ATM networks and broadband IP networks, it gave a requirement based strategy for QoS service...A fuzzy requirement based strategy for QoS service in broadband networks was presented. With the analysis of QoS service in ATM networks and broadband IP networks, it gave a requirement based strategy for QoS service application with Fuzzy language evaluation principles. The requirement parameters are chosen according to the WANT/COST rule, and a fuzzy set is constructed to realize the fuzzy determinant. The simulation results show that it is useful to evaluate the QoS service in broadband networks, and to effectively simplify the access protocols and solve the billing issues in broadband networks.展开更多
One algorithm and one method for PNNI(Private Network to Network Interface) routing were presented. The algorithm is OIL (Older Is Leader) algorithms for Peer Group selection, and the method is the DOO (Distributed ob...One algorithm and one method for PNNI(Private Network to Network Interface) routing were presented. The algorithm is OIL (Older Is Leader) algorithms for Peer Group selection, and the method is the DOO (Distributed object-oriented) method for HDOS (Hierarchy Distributed-Object System), PNNI systems and IP(Internet Protocol) networks. Based on the specifications from ATM forum, and the creative ideas from Distributed System realization, this paper studies and analyzes the private ATM network environment. The OIL algorithm and the DOO method are both for PNNI routing protocol. Through the PNNI simulation, the availability and robustness are proved for the above two improvements.展开更多
In this paper we consider a Markov chain model in an ATM network, which has been studied by Dag and Stavrakakis. On the basis of the iterative formulas obtained by Dag and Stavrakakis, we obtain the explicit analytica...In this paper we consider a Markov chain model in an ATM network, which has been studied by Dag and Stavrakakis. On the basis of the iterative formulas obtained by Dag and Stavrakakis, we obtain the explicit analytical expression of the transition probability matrix. It is very simple to calculate the transition probabilities of the Markov chain by these expressions. In addition, we obtain some results about the structure of the transition probability matrix, which are helpful in numerical calculation and theoretical analysis.展开更多
In classical IPOA, the communication of two users between local AsynchronousTransfer Mode (ATM) ports needs a VCC, however, it is not an elegant solution to the ATM accessequipments design when the performance of the ...In classical IPOA, the communication of two users between local AsynchronousTransfer Mode (ATM) ports needs a VCC, however, it is not an elegant solution to the ATM accessequipments design when the performance of the whole system is considered. Thus, we investigate theway to provide the improved IPOA protocol that uses switching way in local ports. And it is fullycompatible with the CIPOA by using the same protocol for ARP and IP forwarding. In addition, we alsopresent the design of one 10/100 Mbit/s auto adaptive IPOA client board with local switch abilityidea and CAM mechanism for our project.展开更多
A buffer sharing scheme need to meet many competing objectives like robustness to changes in traffic conditions, fairness, efficiency, implementation simplicity, etc. Of the existing techniques, Push Out (PO) is optim...A buffer sharing scheme need to meet many competing objectives like robustness to changes in traffic conditions, fairness, efficiency, implementation simplicity, etc. Of the existing techniques, Push Out (PO) is optimum in terms of overall cell loss performance, but its delay performance is worse than that of all other methods for the multiple space priority. Another scheme named Dynamic Threshold (DT) is robust and adaptive which has good delay performance. A hybrid technique named Dynamic Threshold wi...展开更多
Nowadays the self-healing techniques in ATM networks are highly considered. However, in mostof networks, the normal control and sell-healing control are separately considered. In this paper, intenttedATM VP-based cont...Nowadays the self-healing techniques in ATM networks are highly considered. However, in mostof networks, the normal control and sell-healing control are separately considered. In this paper, intenttedATM VP-based control strategies for ATM survivable networks are prOPosed, which combine the normalcontrol and self-healing control in a unified wad, being able to operate under both normal conditions andcatastrophic failure situations. These strategies allow a cost-effective network plan and design.展开更多
Connection Admission Control(CAC)in ATM networks is the set o/actions taken by the networkto decide whether to accept connection requests during the phase of call establishment or call re-negotiation.CAC is an integra...Connection Admission Control(CAC)in ATM networks is the set o/actions taken by the networkto decide whether to accept connection requests during the phase of call establishment or call re-negotiation.CAC is an integral part of the preventive congestion control in ATM networks whose aim is to ensurenetwork performance.The CAC algorithm has the characteristics of the multitude of control parameters,high degree of computation complexity and strong time restrictions.In this paper we present a CACmechanism featured by combination of foreground control and background learning which is based onneural networks having the capabilities of self-learning and high-Speed processing.A case study is given,after which we discuss the practicability of the proposed algorithm.展开更多
Computer networks are undergoing a remarkable transformation. The widespread use of optical fiber has tremendously increased network bandwidth. Furthermore, greater CPU power, increasing disk capacity, and support for...Computer networks are undergoing a remarkable transformation. The widespread use of optical fiber has tremendously increased network bandwidth. Furthermore, greater CPU power, increasing disk capacity, and support for digital audio and video are creating demand for a new class of network services. For example, video-on-demand (VOD), distant learning, distant diagnosis, video conferences, and many other applications have popped up one after another in recent years. Many of these services have one thing in common. They all require that the same data be sent to multiple recipients. Even in traditional networks, this operation, called multicasting, can not be handled easily and cheaply. When scaled up to high-speed ATM-based networks, the situation becomes more difficult. Multiple data streams travel around the ATM networks with each stream sent to many different destinations simultaneously. Therefore, the networks need a very efficient algorithm for multicast routing. This paper proposes an algorithm for multicast routing in ATM networks. The network routing cost is defined as the combination of the cost of establishing connections, the cost of overall bandwidth and the cost of overall switching. Our routing algorithm generates an optimal multicast routing with minimal overall network cost.展开更多
Considerable protocol development efforts in recent ATM (Asynchronous Transfer Mode) Forum activities have been focused on the traffic management of available bit rate (ABR) service. It has been shown that ABR service...Considerable protocol development efforts in recent ATM (Asynchronous Transfer Mode) Forum activities have been focused on the traffic management of available bit rate (ABR) service. It has been shown that ABR service enables persistent, greedy data sources to efficiently utilize ATM network resources with the help of a rate-based flow control mechanism. ATM Forum Traffic Management Specification Version 4.0 document gives a complete description of the end system behavior of the flow control mechanism, but it leaves the details of the switch behavior to be vendor-implementation dependent. For the sake of compatibility and interoperation among flow control mechanisms implemented by vendors, two rate-based mechanisms EPRCA (Enhanced Proportional Rate Control Algorithm) and ERICA (Explicit Rate Indication for Congestion Avoidance) have been recommended in the specification. In this paper, the mechanisms are studied and their performance is analyzed and compared with a material network. Simulation shows that ERICA is significantly better than EPRCA in the performance of steady state and instantaneous state of source end system ACR (Allowed Cell Rate) and buffer queue of bottleneck switch.展开更多
A transfer line can be modeled as a linear system on maximal algebra. The model is also suitable to ATM and other rate-based communication systems. In respect to the rate-based speciality, a periodical input is consid...A transfer line can be modeled as a linear system on maximal algebra. The model is also suitable to ATM and other rate-based communication systems. In respect to the rate-based speciality, a periodical input is considered as the system' s controller. Then some results in utilization, stability and congestion have been obtained. By use of them, we design an algorithm which integrates routing, resource allocation and flow control into a closed-loop architecture. It is adaptive and solves the prob-lem of congestion and uneven resource utilization. It also succeeds in controlling delay and delay jitter.展开更多
文摘The explicit rate flow control mechanisms for ABR service are used to sharethe available bandwidth of a bottleneck link fairly and reasonably among many competitive users andto maintain the buffer queue length of a bottleneck switch connected to the link at a desired levelin order to avoid and control congestion in ATM networks. However, designing effective flow controlmechanisms for the service is known to be difficult because of the variety of dynamic parametersinvolved such as available link bandwidth, burst of the traffic, the distances between ABR sourcesand switches. In this paper, we present a fuzzy explicit rate flow control mechanism for ABRservice. The mechanism has a simple structure and is robust in the sense that the mechanism'sstability is not sensitive to the change in the number of active virtual connections (VCs). Manysimulations show that this mechanism can not only effectively avoid network congestion, but alsoensure fair share of the bandwidth for all active VCs regardless of the number of hops theytraverse. Additionally, it has the advantages of fast convergence, low oscillation, and high linkbandwidth utilization.
基金This project was supported partly by the Outstanding Youth Scientific Foundation of China(60525303)the National Natural Science Foundation of China(60404022, 60604012)the Natural Science Foundation of Hebei Province of China(F2005000390).
文摘One of the more challenging and unresolved issues in ATM networks is the congestion control of available bit rate (ABR). The dynamic controller is designed based on the control theory and the feedback mechanism of explicit rates With the given method of a chosen parameter, it can guarantee the stability of the controller and closed loop system with propagation delay and bandwidth oscillation. It needs less parameters(only one) to be designed. The queue length can converge to the given value in the least steps. The fairness of different connections is considered further. The simulations show better performance and good quality of service(QoS) is achieved.
基金the open subject for Key Laboratory of Process Industry Automation of Ministry of Education.
文摘For the Asynchronous Transfer Mode (ATM) networks with time-varying multiple time-delays, a more realistic model for the available bit rate (ABR) traffic class with explicit rate feedback is introduced. A fuzzy-immune controller is designed, which can adjust the rates of ABR on-line, overcome the bad effect caused by the saturation nonlinearity and satisfy the weighted fairness. Also, the sufficient condition that guarantees the stability of the closed-loop system with a fuzzy-immune controller is presented in theory for the first time. The algorithm exhibits good performance, and most importantly, has a solid theoretical foundation and can be implemented in practice easily. Simulation results show that the control system is rapid, adaptive, robust, and meanwhile, the quality of service (QoS) is guaranteed.
基金the National Natural Science Foundation of China (No.60274009)Specialized Research Fund for the DoctoralProgram of Higher Education (No.20020145007)
文摘A binary available bit rate (ABR) scheme based on discrete-time variable structure control (DVSC) theory is proposed to solve the problem of asynchronous transfer mode (ATM) networks congestion in this paper. A discrete-time system model with uncertainty is introduced to depict the time-varying ATM networks. Based on the system model, an asymptotically stable sliding surface is designed by linear matrix inequality (LMI). In addition, a novel discrete-time reaching law that can obviously reduce chatter is also put forward. The proposed discrete-time variable structure controller can effectively constrain the oscillation of allowed cell rate (ACR) and the queue length in a router. Moreover, the controller is self-adaptive against the uncertainty in the system. Simulations are done in different scenarios. The results demonstrate that the controller has better stability and robustness than the traditional binary flow controller, so it is good for adequately exerting the simplicity of binary flow control mechanisms.
基金Supported by Shanghai Post & Telecom Administration-SJTU Information and Telecom Joint Lab Project(1999-GR1-3)
文摘A new ant-algorithm-based routing approach is proposed for the VC routing problem with considering the comprehensive effect between the resource utilization and the load balance in ATM networks. In the approach, the backup paths are calculated first, and then an ant algorithm based on the ability of ants to find the shortest path between their nest and the food source during their searching food, is constructed to optimize the VC global route. Simulation results show that the proposed approach can realize VC routing effectively according to the current traffic states in the networks and the user-specified delay requirements.
文摘A new neural network based method for solving the problem of congestion control arising at the user network interface (UNI) of ATM networks is proposed in this paper. Unlike the previous methods where the coding rate for all traffic sources as controller output signals is tuned in a body, the proposed method adjusts the coding rate for only a part of the traffic sources while the remainder sources send the cells in the previous coding rate in case of occurrence of congestion. The controller output signals include the source coding rate and the percentage of the sources that send cells at the corresponding coding rate. The control methods not only minimize the cell loss rate but also guarantee the quality of information (such as voice sources) fed into the multiplexer buffer. Simulations with 150 ADPCM voice sources fed into the multiplexer buffer showed that the proposed methods have advantage over the previous methods in the aspect of the performance indices such as cell loss rate (CLR) and voice quality.
文摘In this paper, an extended Kendall model for the priority scheduling input-line group output with multi-channel in Asynchronous Transfer Mode (ATM) exchange system is proposed and then the mean method is used to model mathematically the non-typical non-anticipative PRiority service (PR) model. Compared with the typical and non-anticipative PR model, it expresses the characteristics of the priority scheduling input-line group output with multi-channel in ATM exchange system. The simulation experiment shows that this model can improve the HOL block and the performance of input-queued ATM switch network dramatically. This model has a better developing prospect in ATM exchange system.
基金Supported by the National Natural Foundation of China (No.60174010 and No.60404022) and the Key Scientific Research Project of the Education Ministry of China (No.204014)
文摘The single bottleneck node of ATM networks is considered. The virtual queue mechanism and the method of proportion-integral-differential(PID) control are adopted in the congestion control. The sufficient condition of the considered system’s stability is given. The method of determining the PID parameters is given further. To quicken the speed of startup and remove the congestion rapidly, the factors of increase and decrease are set according to the length of queue. The result of simulation shows that the system, given an appropriate group of parameters, can acquire good robustness and dynamic performance, and guarantees the quality of service at the same time.
文摘Aim To Put forward an improve algorithm for real-time connection admission control (CAC) decision. Methods converted equations of Cell loss ratio (CLR) upper bound were derived based on typical approaches to reduce computing load. Moreover, the effects of usage parameter control (UPC) policing and bandwidth allocation functions were combined to deduce improver equations. computing load and admission region of the new algorithm were analyzed, while numerical examples and comparisons with classical non-parametic method were also included. Results Computing burden was reduced. More accurate estimation of CLR was obtained. The admission region of new algorithm was larger than typical non-parametric approach and was variable according to the burst length.Conclusion The calculation burden of new algorithm for CLR estimation is lighter than classical non-parametric approach. In addition to that, just as many information as what we can get in connection setup process are used for CAC decision. So it is not only a practicable but also an effective method that can be used in real-time processing.
基金Supported by the National Natural Science Foundation of China (61101129)Specialized Research Fund for the Doctoral Program of Higher Education(20091101110019)
文摘To enhance the fidelity and accuracy of the simulation of communication networks,hardware-in-the-loop(HITL) simulation was employed.HITL simulation methods was classified into three categories,of which the merits and shortages were compared.Combing system-in-the-loop(SITL) simulation principle with high level architecture(HLA),an HITL simulation model of asynchronous transfer mode(ATM) network was constructed.The throughput and end-to-end delay of all-digital simulation and HITL simulation was analyzed,which showed that HITL simulation was more reliable and effectively improved the simulation credibility of communication network.Meanwhile,HLA-SITL method was fast and easy to achieve and low-cost during design lifecycle.Thus,it was a feasible way to research and analyze the large-scale network.
基金National‘86 3’ High Technolgy Plan!(86 3-317-0 1-0 1-0 1-99)
文摘A fuzzy requirement based strategy for QoS service in broadband networks was presented. With the analysis of QoS service in ATM networks and broadband IP networks, it gave a requirement based strategy for QoS service application with Fuzzy language evaluation principles. The requirement parameters are chosen according to the WANT/COST rule, and a fuzzy set is constructed to realize the fuzzy determinant. The simulation results show that it is useful to evaluate the QoS service in broadband networks, and to effectively simplify the access protocols and solve the billing issues in broadband networks.
文摘One algorithm and one method for PNNI(Private Network to Network Interface) routing were presented. The algorithm is OIL (Older Is Leader) algorithms for Peer Group selection, and the method is the DOO (Distributed object-oriented) method for HDOS (Hierarchy Distributed-Object System), PNNI systems and IP(Internet Protocol) networks. Based on the specifications from ATM forum, and the creative ideas from Distributed System realization, this paper studies and analyzes the private ATM network environment. The OIL algorithm and the DOO method are both for PNNI routing protocol. Through the PNNI simulation, the availability and robustness are proved for the above two improvements.
基金This work is supported by the National Key Project of China(No 970211017,the National Natural Science Foundation of China(No,10271102)and Hebei Province Doctoral Foundation(No.2002131)
文摘In this paper we consider a Markov chain model in an ATM network, which has been studied by Dag and Stavrakakis. On the basis of the iterative formulas obtained by Dag and Stavrakakis, we obtain the explicit analytical expression of the transition probability matrix. It is very simple to calculate the transition probabilities of the Markov chain by these expressions. In addition, we obtain some results about the structure of the transition probability matrix, which are helpful in numerical calculation and theoretical analysis.
文摘In classical IPOA, the communication of two users between local AsynchronousTransfer Mode (ATM) ports needs a VCC, however, it is not an elegant solution to the ATM accessequipments design when the performance of the whole system is considered. Thus, we investigate theway to provide the improved IPOA protocol that uses switching way in local ports. And it is fullycompatible with the CIPOA by using the same protocol for ARP and IP forwarding. In addition, we alsopresent the design of one 10/100 Mbit/s auto adaptive IPOA client board with local switch abilityidea and CAM mechanism for our project.
文摘A buffer sharing scheme need to meet many competing objectives like robustness to changes in traffic conditions, fairness, efficiency, implementation simplicity, etc. Of the existing techniques, Push Out (PO) is optimum in terms of overall cell loss performance, but its delay performance is worse than that of all other methods for the multiple space priority. Another scheme named Dynamic Threshold (DT) is robust and adaptive which has good delay performance. A hybrid technique named Dynamic Threshold wi...
文摘Nowadays the self-healing techniques in ATM networks are highly considered. However, in mostof networks, the normal control and sell-healing control are separately considered. In this paper, intenttedATM VP-based control strategies for ATM survivable networks are prOPosed, which combine the normalcontrol and self-healing control in a unified wad, being able to operate under both normal conditions andcatastrophic failure situations. These strategies allow a cost-effective network plan and design.
文摘Connection Admission Control(CAC)in ATM networks is the set o/actions taken by the networkto decide whether to accept connection requests during the phase of call establishment or call re-negotiation.CAC is an integral part of the preventive congestion control in ATM networks whose aim is to ensurenetwork performance.The CAC algorithm has the characteristics of the multitude of control parameters,high degree of computation complexity and strong time restrictions.In this paper we present a CACmechanism featured by combination of foreground control and background learning which is based onneural networks having the capabilities of self-learning and high-Speed processing.A case study is given,after which we discuss the practicability of the proposed algorithm.
基金the National Natural Science Foundation of China! (No.6 970 30 0 7) State High- Tech Developm ents Plan of China!(86 3- 30
文摘Computer networks are undergoing a remarkable transformation. The widespread use of optical fiber has tremendously increased network bandwidth. Furthermore, greater CPU power, increasing disk capacity, and support for digital audio and video are creating demand for a new class of network services. For example, video-on-demand (VOD), distant learning, distant diagnosis, video conferences, and many other applications have popped up one after another in recent years. Many of these services have one thing in common. They all require that the same data be sent to multiple recipients. Even in traditional networks, this operation, called multicasting, can not be handled easily and cheaply. When scaled up to high-speed ATM-based networks, the situation becomes more difficult. Multiple data streams travel around the ATM networks with each stream sent to many different destinations simultaneously. Therefore, the networks need a very efficient algorithm for multicast routing. This paper proposes an algorithm for multicast routing in ATM networks. The network routing cost is defined as the combination of the cost of establishing connections, the cost of overall bandwidth and the cost of overall switching. Our routing algorithm generates an optimal multicast routing with minimal overall network cost.
基金the National Natural Science Foundation of China (No.69896249).
文摘Considerable protocol development efforts in recent ATM (Asynchronous Transfer Mode) Forum activities have been focused on the traffic management of available bit rate (ABR) service. It has been shown that ABR service enables persistent, greedy data sources to efficiently utilize ATM network resources with the help of a rate-based flow control mechanism. ATM Forum Traffic Management Specification Version 4.0 document gives a complete description of the end system behavior of the flow control mechanism, but it leaves the details of the switch behavior to be vendor-implementation dependent. For the sake of compatibility and interoperation among flow control mechanisms implemented by vendors, two rate-based mechanisms EPRCA (Enhanced Proportional Rate Control Algorithm) and ERICA (Explicit Rate Indication for Congestion Avoidance) have been recommended in the specification. In this paper, the mechanisms are studied and their performance is analyzed and compared with a material network. Simulation shows that ERICA is significantly better than EPRCA in the performance of steady state and instantaneous state of source end system ACR (Allowed Cell Rate) and buffer queue of bottleneck switch.
文摘A transfer line can be modeled as a linear system on maximal algebra. The model is also suitable to ATM and other rate-based communication systems. In respect to the rate-based speciality, a periodical input is considered as the system' s controller. Then some results in utilization, stability and congestion have been obtained. By use of them, we design an algorithm which integrates routing, resource allocation and flow control into a closed-loop architecture. It is adaptive and solves the prob-lem of congestion and uneven resource utilization. It also succeeds in controlling delay and delay jitter.