中文摘要：

提出了一种session级别的flash crowd控制策略SGAC（session-granularity admission control）,将session控制粒度和request控制粒度相结合,采用请求平均返回时延作为检测和控制的依据.对session采取一旦接受就完成的策略,在实现对服务器过载控制的同时,保护用户session的完整性,并能自动调节新session的准入速率,以提高服务器利用率.采用真实HTTP Log进行模拟,结果表明,SGAC方法能够有效控制服务器过载,保护session的完整性,提高服务器利用率,降低接入端路由器计算开销,保护有价值的交易session

英文摘要：

An adaptive session-granularity admission control（SGAC） method,which combines the session and request granularities,is proposed for flash crowd control.In SGAC,the average response delay is used to measure,detect,and control the flash crowd.Once a session is allowed to access the server,it will be served until it ends.Besides preventing a server from overloading,SGAC can protect the sessions’ integrity.By regulating the session served number adaptively,SGAC can improve the server’s utilization.The performance of SGAC with real HTTP log are evaluated,and the result show that SGAC can effectively prevent servers from overloading,protect sessions’ integrity,improve server’s utilization,reduce the request arrival rate,reduce the access router’s computing overhead,and protect valuable transaction sessions