Metropolitan ring networks are usually used to connect the high speed backbone networks with the high speed access networks. Until now, metropolitan networks and access networks are gained much attention of researchers just as in separate direction. In this work, we study an interconnected Multi-Ring Network (MRN) architecture in which a Metropolitan Access (MA) Ring is interconnected by a Metropolitan Core (MC) Ring via a Hub Node who is in charge of the synchronization between them. The synchronization in this architecture is the major problem. To solve this problem, we propose a new mechanism called Common-Used Timer Mechanism (CUTM) inspired from CoS-Upgrade Mechanism (CUM) to create well filled optical packets in the hub. CUTM is developed and also integrated as a module to the software Network Simulator 2 (NS2), to simulate the behavior of the MRN considered. We compare the performance of this mechanism with the opportunistic one. The results have shown that, compared to existing solutions, the CUTM enhances the network throughput, optimizes the use of resources, and also offers a solution to the synchronization problem