Studies Of Key Technology For Clos Matrix

The tendency of transmission network is digital, integrated and broadband, but the appearance of fiber which is as transmission medium gives a more open broad prospect for further developments of transmission network, so optical transmission network is an inevitable result for transmission network. Because optical transmission equipment is the core of the optical transmission network, and the development of optical transmission equipment determines whether the function of optical transmission network can achieve effectively. Clos matrix which is one kind of the ideal matrix equipment to meet the requirement, it is widely used in transmission equipment.Clos matrix constructs large capacity switch networks by using lots of small capacity switch modules. It has the advantage of scalability, flexibility and reliability. The key technology of Clos matrix includes the scalability of Clos matrix and the scheduling algorithm for Clos matrix with QoS. This paper studies the key technology of Clos matrix, the main jobs and contributions are the following three aspects:1. In order to solve the problem of schemes for scalability of Clos matrix, one new scale schem for scalability is proposed in this paper---Double United Scale Scheme. It realizes the purpose of capacity multiple upgrading by uniting two modules of every stage of Clos matrix. Modules of first stage and third stage are logical united which means that their physics characters are not changed but port connections are changed. Modules of second stage are physical united which means that their physics characters are changed and two modules unite into a new one.2. Simulations were carried out to test the performances of all schemes for scalability. Its advantages are shown by contrasting to other schemes; and it has a better blocking performance than other schemes.3. Scheduling algorithms for Clos matrix with QoS are realized. Paull algorithm which is unicast algorithms is analyzed, FFMA algorithm and CenterModuleFanoutFirst algorithm both are multicast algorithms are introduced. Weight matrix and weight tree are introduced during the realization of QoS business based on Paull algorithm and FFMA algorithm. When high-priority link need to be guaranteed, it is faster to find the low-priority link which can be moved by searching for weight tree. Simulations were carried out and the results proved that scheduling algorithms with QoS can function better on the different priority business.