This paper proposes a new communication agent，called CORA(commonobject request agent)．The purpose of this approach is to improve the reliability of commu-nication using time-out in open distributed system based on client/server model．In CORA model, the application client could have more control over server'S processing the request through the feedback mechanism of timesegment transaction．and provide time-out's handling for preventing the bad propagation of the partial failure SO that the whole system becomes more rohust．