It is an important problem that how can continue to function correctly and to provide the intended services to legitimate user in a timely manner even in the face of an attack.An intrusion tolerant architecture

which is based on role-based access control scheme

is proposed in this paper.Our method is built upon the analysis of intrusion effects rather than intrusion causes.The characteristics

model and components of intrusion tolerant architecture are discussed in detail.In the distributed network computing environment

utilized the strategy of role-based access control

the intrusion tolerant mechanism is expounded from role-administer server

role pretending

data server and application server.The presented intrusion tolerant architecture guarantees the security and availability of the protected server

which enhances intrusion tolerant ability of server.