移动Ad Hoc网络(Mobile Ad Hoc Network,MANET)受限于移动节点的能量、通信链路的带宽、计算和存储能力等一系列因素。如何提高网络的通信带宽和数据吞吐量,仍然是MANET亟待解决的问题。网络编码(Network Coding,NC)是一种发展非常迅速...移动Ad Hoc网络(Mobile Ad Hoc Network,MANET)受限于移动节点的能量、通信链路的带宽、计算和存储能力等一系列因素。如何提高网络的通信带宽和数据吞吐量,仍然是MANET亟待解决的问题。网络编码(Network Coding,NC)是一种发展非常迅速的编码技术,应用于MANET中可有效地增加网络带宽和网络通信量。将滑动窗口机制融入网络编码和协作传输中,可以更好地提高MANET的数据吞吐量。鉴于此,提出一种MANET中基于滑动窗口的网络编码协作算法(Sliding Window-based Network Coding Cooperative algorithm in MANET,SWNC-CM)。源节点首先对需要发送的数据分组进行编码,然后将编码的数据分组在协作传输机制中传送到下一个节点,目的节点接收到编码数据分组后,根据网络编码的解码机制对数据分组进行解码,从而恢复原始数据。在SWNC-CM中,主要关注滑动窗口、随机线性网络编码方法以及协作传输数据问题。当使用SWNC-CM算法时,并不是所有的数据分组都需要编码,只是对那些在同一个窗口中的数据分组利用随机网络编码方法进行编码,目的节点就可以使用高斯消去法进行解码操作,从而降低编码/解码的计算复杂性。使用网络仿真软件NS2(Network Simulator version 2),以数据吞吐量、解码延迟和分组丢失率等为指标,对SWNC-CM算法进行仿真实验研究。仿真实验结果表明,SWNC-CM算法能较好地提高网络的数据吞吐量,并降低分组丢失率。展开更多
Most of the classical self-similar traffic models are asymptotic in nature. Therefore, it is crucial for an appropriate buffer design of a switch and queuing based performance evaluation. In this paper, we investigate...Most of the classical self-similar traffic models are asymptotic in nature. Therefore, it is crucial for an appropriate buffer design of a switch and queuing based performance evaluation. In this paper, we investigate delay and loss behavior of the switch under self-similar fixed length packet traffic by modeling it as CMMPP/D/1 and CMMPP/D/1/K, respectively, where Circulant Markov Modulated Poisson Process (CMMPP) is fitted by equating the variance of CMMPP and that of self-similar traffic. CMMPP model is already the validated one to emulate the self-similar characteristics. We compare the analytical results with the simulation ones.展开更多
In this paper, we analyze the queueing behaviour of wavelength division multiplexing (WDM) Internet router employing partial buffer sharing (PBS) mechanism with self-similar traffic input. In view of WDM technology in...In this paper, we analyze the queueing behaviour of wavelength division multiplexing (WDM) Internet router employing partial buffer sharing (PBS) mechanism with self-similar traffic input. In view of WDM technology in networking, each output port of the router is modelled as multi-server queueing system. To guarantee the quality of service (QoS) in Broadband integrated services digital network (B-ISDN), PBS mechanism is a promising one. As Markov modulated Poisson process (MMPP) emulates self-similar Internet traffic, we can use MMPP as input process of queueing system to investigate queueing behaviour of the router. In general, as network traffic is asynchronous (unslotted) and of variable packet lengths, service times (packet lengths) are assumed to follow Erlang-k distribution. Since, the said distribution is relatively general compared to deterministic and exponential. Hence, specific output port of the router is modelled as MMPP/Ek/s/C queueing system. The long-term performance measures namely high priority and low priority packet loss probabilities and the short-term performance measures namely mean lengths of critical and non-critical periods against the system parameters and traffic parameters are computed by means of matrix-geometric methods and approximate Markovian model. This kind of analysis is useful in dimensioning the router under self-similar traffic input employing PBS mechanism to provide differentiated services (DiffServ) and QoS guarantee.展开更多
文摘移动Ad Hoc网络(Mobile Ad Hoc Network,MANET)受限于移动节点的能量、通信链路的带宽、计算和存储能力等一系列因素。如何提高网络的通信带宽和数据吞吐量,仍然是MANET亟待解决的问题。网络编码(Network Coding,NC)是一种发展非常迅速的编码技术,应用于MANET中可有效地增加网络带宽和网络通信量。将滑动窗口机制融入网络编码和协作传输中,可以更好地提高MANET的数据吞吐量。鉴于此,提出一种MANET中基于滑动窗口的网络编码协作算法(Sliding Window-based Network Coding Cooperative algorithm in MANET,SWNC-CM)。源节点首先对需要发送的数据分组进行编码,然后将编码的数据分组在协作传输机制中传送到下一个节点,目的节点接收到编码数据分组后,根据网络编码的解码机制对数据分组进行解码,从而恢复原始数据。在SWNC-CM中,主要关注滑动窗口、随机线性网络编码方法以及协作传输数据问题。当使用SWNC-CM算法时,并不是所有的数据分组都需要编码,只是对那些在同一个窗口中的数据分组利用随机网络编码方法进行编码,目的节点就可以使用高斯消去法进行解码操作,从而降低编码/解码的计算复杂性。使用网络仿真软件NS2(Network Simulator version 2),以数据吞吐量、解码延迟和分组丢失率等为指标,对SWNC-CM算法进行仿真实验研究。仿真实验结果表明,SWNC-CM算法能较好地提高网络的数据吞吐量,并降低分组丢失率。
文摘Most of the classical self-similar traffic models are asymptotic in nature. Therefore, it is crucial for an appropriate buffer design of a switch and queuing based performance evaluation. In this paper, we investigate delay and loss behavior of the switch under self-similar fixed length packet traffic by modeling it as CMMPP/D/1 and CMMPP/D/1/K, respectively, where Circulant Markov Modulated Poisson Process (CMMPP) is fitted by equating the variance of CMMPP and that of self-similar traffic. CMMPP model is already the validated one to emulate the self-similar characteristics. We compare the analytical results with the simulation ones.
文摘In this paper, we analyze the queueing behaviour of wavelength division multiplexing (WDM) Internet router employing partial buffer sharing (PBS) mechanism with self-similar traffic input. In view of WDM technology in networking, each output port of the router is modelled as multi-server queueing system. To guarantee the quality of service (QoS) in Broadband integrated services digital network (B-ISDN), PBS mechanism is a promising one. As Markov modulated Poisson process (MMPP) emulates self-similar Internet traffic, we can use MMPP as input process of queueing system to investigate queueing behaviour of the router. In general, as network traffic is asynchronous (unslotted) and of variable packet lengths, service times (packet lengths) are assumed to follow Erlang-k distribution. Since, the said distribution is relatively general compared to deterministic and exponential. Hence, specific output port of the router is modelled as MMPP/Ek/s/C queueing system. The long-term performance measures namely high priority and low priority packet loss probabilities and the short-term performance measures namely mean lengths of critical and non-critical periods against the system parameters and traffic parameters are computed by means of matrix-geometric methods and approximate Markovian model. This kind of analysis is useful in dimensioning the router under self-similar traffic input employing PBS mechanism to provide differentiated services (DiffServ) and QoS guarantee.
