| As the conversion from traditional telecommunications to IP data networks, Session Initiation Protocol as a multimedia control protocol has become the hottest research for its advantages of simple, common and strong expansion, and variety of applications based on SIP appear. However, SIP did not consider NAT when designed, making SIP communication between private networks and public networks need to rely on ALG. Because ALG and SIP business bond closely in the implementation of the existing SIP-ALG, lead to SIP-ALG supporting business expansion become a difficulty. Therefore, it is necessary to study and design a specific SIP-ALG in which ALG has nothing to do with the SIP business.In my thesis, after studying the issues for SIP to traverse NAT and the characteristics of SIP, a highly configurable and adaptable SIP-ALG framework is designed to unbind ALG and SIP business. In order to implement this framework, a highly configurable middle layer is designed and implement. And the details about decode of configured information, the method of address information match and algorithm complexity are studied, which make the structure more efficient, robust and safe.The framework designed in my thesis can be widely used in various SIP Application Layer Gateway, effectively adapt to SIP new business needs, and greatly reduce the development costs. |
PDF Full Text Request