Recently,switched Ethernet has become an active area of research because of its wide uses in industry.However,its uses have various real-time constraints on data communications.This paper analyzes the performance of t...Recently,switched Ethernet has become an active area of research because of its wide uses in industry.However,its uses have various real-time constraints on data communications.This paper analyzes the performance of the line topology switched Ethernet as a data acquisition network.Network calculus theory,which has been successfully applied to assess the real-time performance of packet-switched networks,is used to analyze the networks.To properly describe the activity of switches,a novel approach of modeling data flows into or out of switches is addressed.Based on our model,a concisely analytical expression of the maximal end-to-end delay in line topology switched Ethernet is derived.Finally,the relative simulation results are demonstrated.These results agree well with the analytical results,and thus they validate the data flow modeling techniques.展开更多
Designing an Ethernet switch that can assure normal interaction of protocol packets between switches in a network environment of massive traffic is an important matter. Taking the L3 Ethernet switch based on Applicati...Designing an Ethernet switch that can assure normal interaction of protocol packets between switches in a network environment of massive traffic is an important matter. Taking the L3 Ethernet switch based on Application Specific Integrated Circuit (ASIC) as an example,this article analyzes several typical issues about packet receiving and sending by the CPU in a multi-progress environment,including CPU load,software and hardware queue settings,and communication mechanism between CPU and the switch chip. This article gives solutions to these issues mentioned above. The solutions are applicable to Network Processor (NP) issues as well.展开更多
A novel technique called physical frame time-slot switching （PFTS） is discussed and its technical and application aspects are analyzed. The format of the ethernet media access control （MAC） frame is borrowed in de...A novel technique called physical frame time-slot switching （PFTS） is discussed and its technical and application aspects are analyzed. The format of the ethernet media access control （MAC） frame is borrowed in defining the physical frame for PFTS and the transmission time for the maximum size of the MAC frame is defined as a physical frame time-slot （PFT）. Consequently, user data can be fed into PFTS and switched in a single layer sub-network in an asynchronous mode.展开更多
为了满足未来大容量、高速率、硬实时性的信息传输需求,将交换式以太网技术引入列车通信网络(TCN,train communication network)。针对不同优先级消息,根据其通信调度方式对传输过程建立了TCN的确定与随机Petri网(DSPN,determined and s...为了满足未来大容量、高速率、硬实时性的信息传输需求,将交换式以太网技术引入列车通信网络(TCN,train communication network)。针对不同优先级消息,根据其通信调度方式对传输过程建立了TCN的确定与随机Petri网(DSPN,determined and stochastic Petri nets)模型,比较了交换机不同调度算法对时延的影响,并分析了消息数目和产生周期,以及消息数目和吞吐量的关系。实验结果表明,采用优先级调度算法能在牺牲非实时数据时延的条件下降低实时数据的时延,验证了采用交换式以太网的TCN吞吐量远超过现有的TCN,并且能够为今后的设计和优化提供理论依据。展开更多
文摘Recently,switched Ethernet has become an active area of research because of its wide uses in industry.However,its uses have various real-time constraints on data communications.This paper analyzes the performance of the line topology switched Ethernet as a data acquisition network.Network calculus theory,which has been successfully applied to assess the real-time performance of packet-switched networks,is used to analyze the networks.To properly describe the activity of switches,a novel approach of modeling data flows into or out of switches is addressed.Based on our model,a concisely analytical expression of the maximal end-to-end delay in line topology switched Ethernet is derived.Finally,the relative simulation results are demonstrated.These results agree well with the analytical results,and thus they validate the data flow modeling techniques.
文摘Designing an Ethernet switch that can assure normal interaction of protocol packets between switches in a network environment of massive traffic is an important matter. Taking the L3 Ethernet switch based on Application Specific Integrated Circuit (ASIC) as an example,this article analyzes several typical issues about packet receiving and sending by the CPU in a multi-progress environment,including CPU load,software and hardware queue settings,and communication mechanism between CPU and the switch chip. This article gives solutions to these issues mentioned above. The solutions are applicable to Network Processor (NP) issues as well.
基金Supported by National Natural Science Foundation of China (No. 60372065)
文摘A novel technique called physical frame time-slot switching （PFTS） is discussed and its technical and application aspects are analyzed. The format of the ethernet media access control （MAC） frame is borrowed in defining the physical frame for PFTS and the transmission time for the maximum size of the MAC frame is defined as a physical frame time-slot （PFT）. Consequently, user data can be fed into PFTS and switched in a single layer sub-network in an asynchronous mode.
文摘为了满足未来大容量、高速率、硬实时性的信息传输需求,将交换式以太网技术引入列车通信网络(TCN,train communication network)。针对不同优先级消息,根据其通信调度方式对传输过程建立了TCN的确定与随机Petri网(DSPN,determined and stochastic Petri nets)模型,比较了交换机不同调度算法对时延的影响,并分析了消息数目和产生周期,以及消息数目和吞吐量的关系。实验结果表明,采用优先级调度算法能在牺牲非实时数据时延的条件下降低实时数据的时延,验证了采用交换式以太网的TCN吞吐量远超过现有的TCN,并且能够为今后的设计和优化提供理论依据。
