CSMA(carrier sense multiple access)即载波侦听多路访问/冲突检测,或“带有冲突检测的载波侦听多路访问”。由于CSMA网络具有探测侦听功能,因此介绍了由89S52单片机组成CSMA网络的基本原理和HDLC通讯规程的应用、循环冗余码校验的原...CSMA(carrier sense multiple access)即载波侦听多路访问/冲突检测,或“带有冲突检测的载波侦听多路访问”。由于CSMA网络具有探测侦听功能,因此介绍了由89S52单片机组成CSMA网络的基本原理和HDLC通讯规程的应用、循环冗余码校验的原理及具体应用,并给出了它们的软件设计流程。展开更多
Using CSMA/CD for EPON can eliminate the augmentations, such as multi-point control protocol and point-to-point emulation, added to the existing 802.3 architecture due to the incompatibility of PON to Ethernet. Both f...Using CSMA/CD for EPON can eliminate the augmentations, such as multi-point control protocol and point-to-point emulation, added to the existing 802.3 architecture due to the incompatibility of PON to Ethernet. Both full-duplex EPON system and half-duplex EPON system using CSMA/CD were proposed. In the full-duplex EPON, CSMA/CD is used as the upstream MAC protocol. In the half-duplex EPON system, both upstream and downstream traffic contend for the optical channel through CSMA/CD protocol. The upstream lightwave redirection and collision detection techniques were given. By the analysis and simulation, the throughput performance of the half-duplex EPON system is proven to be as well as that of the existing high speed half-duplex Ethernet LAN.展开更多
It is known that packet collisions in wireless networks will deteriorate system performance, hence substantial efforts have been made to avoid collision in multi-user access designs. Also, there have been many studies...It is known that packet collisions in wireless networks will deteriorate system performance, hence substantial efforts have been made to avoid collision in multi-user access designs. Also, there have been many studies on throughput analysis of CSMA wireless networks. However, for a typical CSMA network in which not all nodes can sense each other, it is still not well investigated how link throughputs are affected by collisions. We note that in practical 802.11-like networks, the time is divided into mini-timeslots and packet collisions are in fact unavoidable. Thus, it is desirable to move forward to explore how collisions in such a network will affect system performance. Based on the collision-free ideal CSMA network(ICN) model, this paper attempts to analyze link throughputs when taking the backoff collisions into account and examine the effect of collisions on link throughputs. Specifically, we propose an Extended Ideal CSMA Network(EICN) model to characterize the collision effects as well as the interactions and dependency among links in the network. Based on EICN, we could directly compute link throughputs and collision probabilities. Simulations show that the EICN model is of high accuracy. Under various network topologies and protocol parameter settings, the computation error of link throughputs using EICN is kept to 4% or below. Interestingly, we find that unlike expected, the effect of collisions on link throughputs in a modest CSMA wireless network is not significant, which enriches our understanding on practical CSMA wireless networks such as Wi-Fi.展开更多
IEEE是英文Institute of Electrical and Electronics Engineers的简称．其中文译名是电气和电子工程师协会。该协会的总部设在美国．主要开发数据通信标准及其他标准。IEEE802委员会负责起草局域网草案，并送交美国国家标准协会(ANSI)...IEEE是英文Institute of Electrical and Electronics Engineers的简称．其中文译名是电气和电子工程师协会。该协会的总部设在美国．主要开发数据通信标准及其他标准。IEEE802委员会负责起草局域网草案，并送交美国国家标准协会(ANSI)批准和在美国国内标准化。IEEE还把草案送交国际标准化组织(ISO)。ISO把这个802规范称为ISO8802标准，因此。展开更多
文摘CSMA(carrier sense multiple access)即载波侦听多路访问/冲突检测,或“带有冲突检测的载波侦听多路访问”。由于CSMA网络具有探测侦听功能,因此介绍了由89S52单片机组成CSMA网络的基本原理和HDLC通讯规程的应用、循环冗余码校验的原理及具体应用,并给出了它们的软件设计流程。
文摘Using CSMA/CD for EPON can eliminate the augmentations, such as multi-point control protocol and point-to-point emulation, added to the existing 802.3 architecture due to the incompatibility of PON to Ethernet. Both full-duplex EPON system and half-duplex EPON system using CSMA/CD were proposed. In the full-duplex EPON, CSMA/CD is used as the upstream MAC protocol. In the half-duplex EPON system, both upstream and downstream traffic contend for the optical channel through CSMA/CD protocol. The upstream lightwave redirection and collision detection techniques were given. By the analysis and simulation, the throughput performance of the half-duplex EPON system is proven to be as well as that of the existing high speed half-duplex Ethernet LAN.
基金partially supported by the National Natural Science Foundation of China under Grant 61571178,Grant 61771315 and Grant 61501160
文摘It is known that packet collisions in wireless networks will deteriorate system performance, hence substantial efforts have been made to avoid collision in multi-user access designs. Also, there have been many studies on throughput analysis of CSMA wireless networks. However, for a typical CSMA network in which not all nodes can sense each other, it is still not well investigated how link throughputs are affected by collisions. We note that in practical 802.11-like networks, the time is divided into mini-timeslots and packet collisions are in fact unavoidable. Thus, it is desirable to move forward to explore how collisions in such a network will affect system performance. Based on the collision-free ideal CSMA network(ICN) model, this paper attempts to analyze link throughputs when taking the backoff collisions into account and examine the effect of collisions on link throughputs. Specifically, we propose an Extended Ideal CSMA Network(EICN) model to characterize the collision effects as well as the interactions and dependency among links in the network. Based on EICN, we could directly compute link throughputs and collision probabilities. Simulations show that the EICN model is of high accuracy. Under various network topologies and protocol parameter settings, the computation error of link throughputs using EICN is kept to 4% or below. Interestingly, we find that unlike expected, the effect of collisions on link throughputs in a modest CSMA wireless network is not significant, which enriches our understanding on practical CSMA wireless networks such as Wi-Fi.
文摘IEEE是英文Institute of Electrical and Electronics Engineers的简称．其中文译名是电气和电子工程师协会。该协会的总部设在美国．主要开发数据通信标准及其他标准。IEEE802委员会负责起草局域网草案，并送交美国国家标准协会(ANSI)批准和在美国国内标准化。IEEE还把草案送交国际标准化组织(ISO)。ISO把这个802规范称为ISO8802标准，因此。
