| Summary: | 碩士 === 國立成功大學 === 電機工程學系 === 87 === [Abstract]
Requirements of high-capacity, high-speed, and high-quality transmission advance the development of optical network and networking technology. To ensure QoS, restoration plays an important role as a networking technique. Because of standard of B-ISDN reference model, most of papers discuss about restoration proposal over asynchronous transfer mode (ATM) network in recent years. This paper proposes a dynamic self-healing scheme under the platform of synchronous optical network (SONET) or ATM network architecture.
A hierarchical TCP/IP/ATM/SONET/WDM is fabricated for consideration of the layered transmission and management. For proposed restoration, network should be reconfigured to a ring-based network by our checking rule. The whole scheme provides an optimal operation environment for the large-scale network backbone. And traditional restoration is used in subnet. Automatic protection switch (APS), dual homing (DH), and self-healing ring (SHR) are applied in small-scale network. It is just like the route information protocol (RIP) being implemented for small scale network and the open shortest path first (OSPF) protocol being suitable for larger scale network. In ATM network, traffic service can be classified into several categories according to timing and bandwidth assignment. Priority scheme is adopted to enhance the system performance. The proposed dynamic restoration algorithm can provide excellent performance for data link requirement of variable bit rate (VBR) service, and achieve higher restoration ratio than pre-planned one.
Due to transmission scheme, Self-Healing Control (SHC) messages in ATM network have more bandwidth than in SONET. Message bundling scheme, two-passed handshaking and three-passed handshaking are discussed. During fine-tuning process, hop limit will be adjusted to optimize the system performance. Finally, the computer simulation evaluation will demonstrate the relation of traffic load, invalid node, restoration ratio and elapse time with the conventional dynamic restoration. The simulation results indicate that the performance of dynamic restoration has been improved obviously by this distributed line-restored ring-based algorithm.
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