| Summary: | 碩士 === 大同大學 === 資訊工程學系(所) === 95 === According to the advancement and popularize of the wireless transmission technology, accessing wireless networks has become convenient nowadays. Traditionally telecommunications use circuit switching to support voice. However, 2.5G and 3G technologies establish packet data communications via Serving GPRS Support Node and Gateway GPRS Support Node. All these technologies have to reserve dedicate lines, bandwidth and equipments to provide services. It causes the inefficiency of the system.
Packet switching can provide more efficient and less expensive wireless networks. However, it does not reverse dedicated channels for specific mobile nodes. It means the connection would fail because of the change of the IP address and routing rules while the mobile node moves from one network to another. SGSN and GGSN are designed to support mobility and handoff. As for the other wireless data networks, only fixed access is supported.
To support mobility and handoff, we are referred to the layered TCP/IP protocol stack and create a new Mobile Node Session Control (MNSC) layer that locates between TCP and Application layers. MNSC can be used to support handoff, connection reestablishment and enhance transmission performance. In the following chapters, we’ll first review the current telecom handoff and session control technologies. And then we will introduce articles discussing IP layer handoff. Finally, we’ll propose a new MNSC architecture and evaluate its performance.
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