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
在教务管理系统中,电子邮件具有重要的作用。着重阐述采用Java Mail API结合JSP和SERVLET等J2EE技术实现Web电子邮件系统的理论基础、设计思想、系统框架及实施验证。首先介绍Web邮件系统所涉及的协议及J2EE Ja-va Mail API的结构框架...在教务管理系统中,电子邮件具有重要的作用。着重阐述采用Java Mail API结合JSP和SERVLET等J2EE技术实现Web电子邮件系统的理论基础、设计思想、系统框架及实施验证。首先介绍Web邮件系统所涉及的协议及J2EE Ja-va Mail API的结构框架。其次对系统的框架进行分析,给出关键模块设计思路,包括系统整体设计,模块设计,层次划分和数据库设计等。最后,对系统具体的实现进行了深入探讨,详细阐述各功能的实现原理、开发步骤及实时效果。展开更多
针对我国首个±1100 k V特高压直流工程(准东—皖南),研究了直流送受端接入系统方案。首先,对于直流送端系统,考虑直流再启动、闭锁等故障对电网的影响,采用直流安全稳定计算标准,从频率和电压稳定性角度研究送端换流站孤岛接入和...针对我国首个±1100 k V特高压直流工程(准东—皖南),研究了直流送受端接入系统方案。首先,对于直流送端系统,考虑直流再启动、闭锁等故障对电网的影响,采用直流安全稳定计算标准,从频率和电压稳定性角度研究送端换流站孤岛接入和联网接入2种方式的可行性。然后,对于直流受端系统,从提高多馈入短路比、抑制短路电流、平衡潮流分布3个层次,研究受端换流站单层接入500 k V、单层接入1000k V、分层接入1000 k V/500 k V这3种方式的可行性。最后,从受端换流站近区网架结构、接入通道选择等多角度研究并提出了换流站的系统接入网架方案。展开更多
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.
文摘在教务管理系统中,电子邮件具有重要的作用。着重阐述采用Java Mail API结合JSP和SERVLET等J2EE技术实现Web电子邮件系统的理论基础、设计思想、系统框架及实施验证。首先介绍Web邮件系统所涉及的协议及J2EE Ja-va Mail API的结构框架。其次对系统的框架进行分析,给出关键模块设计思路,包括系统整体设计,模块设计,层次划分和数据库设计等。最后,对系统具体的实现进行了深入探讨,详细阐述各功能的实现原理、开发步骤及实时效果。
文摘针对我国首个±1100 k V特高压直流工程(准东—皖南),研究了直流送受端接入系统方案。首先,对于直流送端系统,考虑直流再启动、闭锁等故障对电网的影响,采用直流安全稳定计算标准,从频率和电压稳定性角度研究送端换流站孤岛接入和联网接入2种方式的可行性。然后,对于直流受端系统,从提高多馈入短路比、抑制短路电流、平衡潮流分布3个层次,研究受端换流站单层接入500 k V、单层接入1000k V、分层接入1000 k V/500 k V这3种方式的可行性。最后,从受端换流站近区网架结构、接入通道选择等多角度研究并提出了换流站的系统接入网架方案。
