| Number portability is a network service provided by operators that allows subscribers to keep unique telephone number no matter to which service provider they change, what service they choose or where they will be located.During the twenty years since concept of number portability (NP) is raised, many countries have studied and implemented this service. By implementing specific NP service that with some restricts, new and small operators are greatly supported and all operators are promoted to establish their brand awareness, enrich service categories and improve service quality. Meanwhile, NP service greatly saves number resource for the nation. Currently in our country, the three operators are responsible for the promotion of 3G service based on different standard, especially China Mobile Communication Corporation (CMCC). The standard promoted by CMCC is TD-SCDMA which is an independent innovation of China. Considering the differences of the three operator's strength, the implementation of NP service will have great benefit to balance the strength of the three while support the promotion of TD-SCDMA.There are three aspects involved in the NP technology:routing technology by which NP service is implemented, the method of inter-network routing, and management system. This article firstly analyzes the two platforms, intelligent communication network and signal routing function network, on which NP technology is built. Also, the advantages and disadvantages of them are elaborated respectively. Then, we study the inter-network routing of voice call related service and text or multimedia related service. According to the routing design and system demand, we develop the NP management system (NPMS). We focused on the design and coding for service flows. As another key point, center NP database (CNPDB) is fully inspected and the mechanism of high availability and data replication are studies and developed. At last, we discuss the prospect of NP service as 3G and 4G applications are spread. |
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