The OAM (operating and maintenance) module of a router implements the management and manipulation of the router. The OAM is one of the most important sub systems in a router, guaranteeing it to work in going order. With the rapid rate of router technic development, it is becoming increasingly important to dynamically upgrade router software in an incremental fashion. In this paper, the authors make a thorough research on router operating and maintenance system. First, the ESR-OAM designed requirements and evolutions are introduced. Then the extended services router architecture and ESR-OAM function requirements are presented, which is developed by Tsinghua University. And the ESR-OAM is designed and implemented in detail, which can dynamically add and configure extensible component at run time. At last, research directions and open problems in this area are discussed.