软件定义网络(software defined networking,SDN)分离的数据平面和控制平面,给网络管理带来了开放性和灵活性.但同时控制器与交换机之间的接口(控制器南向接口)需要更频繁的交互各种消息以实现对网络的控制.一方面,数据平面触发Table-M...软件定义网络(software defined networking,SDN)分离的数据平面和控制平面,给网络管理带来了开放性和灵活性.但同时控制器与交换机之间的接口(控制器南向接口)需要更频繁的交互各种消息以实现对网络的控制.一方面,数据平面触发Table-Miss的数据包需要通过Packet-In消息往返于交换机与控制器之间,时延增大的同时也给控制器南向接口带来繁重的通信开销,数据平面和控制平面之间的交互容易成为网络性能的瓶颈.另一方面,控制器在下发新的流表项时,由于缺乏新表项对应的数据流特征信息,易出现已有的大流表项被下发的小流表项替换的情况,造成冗余的Flow-Mod消息(流表更新消息)和Packet-In消息,进一步加重了南向接口的通信开销,降低了网络的整体性能.提出一种基于流量特征的OpenFlow南向接口开销优化技术uFlow,在控制器上通过对Packet-In消息中数据流量特征的识别以及对小流的直接转发,达到消除南向接口冗余开销的目的.对uFlow的原型系统进行了实现,并通过真实网络中的流量对uFlow优化效果进行了验证.实验结果显示:与传统的OpenFlow网络处理方式相比,uFlow消除了冗余的交换机流表项更新,显著地降低了OpenFlow南向接口的交互开销:在不同的网络负载和流表容量的情况下,uFlow平均能减少70%以上的Flow-Mod消息.展开更多
目的探讨褪黑素(melatonin,MLT)通过内质网应激发挥抗胃癌作用的机制。方法将体外培养的人胃癌细胞AGS细胞株分为4组,即正常对照组、MLT组、4-PB组和MLT+4-PB组。倒置相差显微镜观察细胞的形态变化,采用CCK-8法检测各组细胞增殖抑制率,...目的探讨褪黑素(melatonin,MLT)通过内质网应激发挥抗胃癌作用的机制。方法将体外培养的人胃癌细胞AGS细胞株分为4组,即正常对照组、MLT组、4-PB组和MLT+4-PB组。倒置相差显微镜观察细胞的形态变化,采用CCK-8法检测各组细胞增殖抑制率,集落试验检测细胞克隆形成,Annexin V FITC/PI流式法检测细胞凋亡,Western Blot法检测细胞蛋白GRP78、ATF6、TRAF-2和Cleaved-caspase-3表达变化。结果褪黑素对胃癌生长、增殖和克隆均有抑制作用。2 mmol/L浓度褪黑素可诱导细胞凋亡,内质网应激抑制剂4-PB可抑制褪黑素促凋亡作用。褪黑素可诱导内质网应激相关蛋白(GRP78、ATF6和TRAF-2)和凋亡相关蛋白(Caspase-3)表达上升,4-PB可使其表达明显减弱。结论褪黑素通过内质网应激通路促进胃癌细胞凋亡,从而发挥抗癌作用。展开更多
Benefited from the design of separating control plane and data plane,software defined networking(SDN)is widely concerned and applied.Its quick response capability to network events with changes in network policies ena...Benefited from the design of separating control plane and data plane,software defined networking(SDN)is widely concerned and applied.Its quick response capability to network events with changes in network policies enables more dynamic management of data center networks.Although the SDN controller architecture is increasingly optimized for swift policy updates,the data plane,especially the prevailing ternary content-addressable memory(TCAM)based flow tables on physical SDN switches,remains unoptimized for fast rule updates,and is gradually becoming the primary bottleneck along the policy update pipeline.In this paper,we present RuleTris,the first SDN update optimization framework that minimizes rule update latency for TCAM-based switches.RuleTris employs the dependency graph(DAG)as the key abstraction to minimize the update latency.RuleTris efficiently obtains the DAGs with novel dependency preserving algorithms that incrementally build rule dependency along with the compilation process.Then,in the guidance of the DAG,RuleTris calculates the TCAM update schedules that minimize TCAM entry moves,which are themain cause of TCAM update inefficiency.In evaluation,RuleTris achieves a median of<12 ms and 90-percentile of<15ms the end-to-end perrule update latency on our hardware prototype,outperforming the state-of-the-art composition compiler CoVisor by～20 times.展开更多
文摘软件定义网络(software defined networking,SDN)分离的数据平面和控制平面,给网络管理带来了开放性和灵活性.但同时控制器与交换机之间的接口(控制器南向接口)需要更频繁的交互各种消息以实现对网络的控制.一方面,数据平面触发Table-Miss的数据包需要通过Packet-In消息往返于交换机与控制器之间,时延增大的同时也给控制器南向接口带来繁重的通信开销,数据平面和控制平面之间的交互容易成为网络性能的瓶颈.另一方面,控制器在下发新的流表项时,由于缺乏新表项对应的数据流特征信息,易出现已有的大流表项被下发的小流表项替换的情况,造成冗余的Flow-Mod消息(流表更新消息)和Packet-In消息,进一步加重了南向接口的通信开销,降低了网络的整体性能.提出一种基于流量特征的OpenFlow南向接口开销优化技术uFlow,在控制器上通过对Packet-In消息中数据流量特征的识别以及对小流的直接转发,达到消除南向接口冗余开销的目的.对uFlow的原型系统进行了实现,并通过真实网络中的流量对uFlow优化效果进行了验证.实验结果显示:与传统的OpenFlow网络处理方式相比,uFlow消除了冗余的交换机流表项更新,显著地降低了OpenFlow南向接口的交互开销:在不同的网络负载和流表容量的情况下,uFlow平均能减少70%以上的Flow-Mod消息.
文摘目的探讨褪黑素(melatonin,MLT)通过内质网应激发挥抗胃癌作用的机制。方法将体外培养的人胃癌细胞AGS细胞株分为4组,即正常对照组、MLT组、4-PB组和MLT+4-PB组。倒置相差显微镜观察细胞的形态变化,采用CCK-8法检测各组细胞增殖抑制率,集落试验检测细胞克隆形成,Annexin V FITC/PI流式法检测细胞凋亡,Western Blot法检测细胞蛋白GRP78、ATF6、TRAF-2和Cleaved-caspase-3表达变化。结果褪黑素对胃癌生长、增殖和克隆均有抑制作用。2 mmol/L浓度褪黑素可诱导细胞凋亡,内质网应激抑制剂4-PB可抑制褪黑素促凋亡作用。褪黑素可诱导内质网应激相关蛋白(GRP78、ATF6和TRAF-2)和凋亡相关蛋白(Caspase-3)表达上升,4-PB可使其表达明显减弱。结论褪黑素通过内质网应激通路促进胃癌细胞凋亡,从而发挥抗癌作用。
基金supported by National Key R&D Program of China under Grant No.2017YFB0801703the Key Research and Development Program of Zhejiang Province under Grant No.2018C01088
文摘Benefited from the design of separating control plane and data plane,software defined networking(SDN)is widely concerned and applied.Its quick response capability to network events with changes in network policies enables more dynamic management of data center networks.Although the SDN controller architecture is increasingly optimized for swift policy updates,the data plane,especially the prevailing ternary content-addressable memory(TCAM)based flow tables on physical SDN switches,remains unoptimized for fast rule updates,and is gradually becoming the primary bottleneck along the policy update pipeline.In this paper,we present RuleTris,the first SDN update optimization framework that minimizes rule update latency for TCAM-based switches.RuleTris employs the dependency graph(DAG)as the key abstraction to minimize the update latency.RuleTris efficiently obtains the DAGs with novel dependency preserving algorithms that incrementally build rule dependency along with the compilation process.Then,in the guidance of the DAG,RuleTris calculates the TCAM update schedules that minimize TCAM entry moves,which are themain cause of TCAM update inefficiency.In evaluation,RuleTris achieves a median of<12 ms and 90-percentile of<15ms the end-to-end perrule update latency on our hardware prototype,outperforming the state-of-the-art composition compiler CoVisor by～20 times.
