Research On Wavelength Router In GMPLS Intelligent Optical Networks

DWDM systems help to maximize the capacity of installed fiber in point-to-point fiber optical communications, however they are only able to provide original band-width of fibers. In order to build cost-effective and flexible DWDM networks, intelligent optical nodes are required. At present, it is a great challenge to realize an all-optics wavelength router since a large dimensional optical switches modules and all optical wavelength converters and other tunable devices are integrated in the system, furthermore, the wavelength cross-connects (WXC) in the system are desired to be modular because it is a requirement of optical network good scalability for the future, and the routing and signaling protocols of Intelligent Optical Networks (ION) are not yet completely standardized at this time of day. The wavelength router is regarded as a combination of the wavelength granularity and IP intelligence. It is an instrument at optical layer and is controlled and managed with the GMPLS protocol suites to be able to realize wavelength routing according to the wavelength addressing and switch the wavelength signals from any input-port to any output-port. Nowadays, the wavelength routers being designed to be O/E/O hybrid structures, and they have no transparency of signal format, and the optical cross-connects (OXC) in the systems are mostly large dimensional optics-mechanical switches or MEMS switches, which are very complex and only transitional products. In this dissertation, the author presents the theoretical and experimental researches on the structure design and implementation of an all-optics wavelength router from the perspective that it must be simplicity, facility, configurability, modularity, and have the capability of wavelength conversion. The main contents are as follows: (1) Conceives the logical and functional structures based on the framework of GMPLS optical networks. The routing controller should have versatile interfaces because it has different peripheral equipments. The signaling messages following TCP/IP protocols are transmitted in the out-of-band wavelength 1310nm. The main functions of a wavelength router are the transmission module of client data, receiving and sending module of the signaling, IP encapsulation module, OSPF-TE protocol module, RSVP-TE protocol module, LMP protocol module and wavelength assignment and de-assignment module. (2) Proposes an analysis model for WXC on insertion loss, flexibility and cost and evaluates multiple schemes of WXCs. (3) Proposes a WXC structure SPN-WXC whose main advantage is having no tunable components and converting multiple wavelengths simultaneously. The proposed design is very similar to a traditional wavelength router structure, but the difference is two fold. First it uses a fixed tuned wavelength converter. This converter converts any input wavelength to a fixed wavelength. Second it allows loop back of the light. With this allowance of loop back, we can achieve the ability of tunable wavelength conversion using a fixed tuned wavelength converter. In comparison with previously reported structures, our design has the advantage of simplicity and cost-effectivity. The max insertion loss of this structure is 21dB. And the simulation experimental results of cascaded connection show insignificant receiver sensitivity degradation due to switching in the wavelength router, indicating that the signal quality is practically independent of the number nodes. (4) Based on the theory of queue, presents a blocking probability model M/M/T/T to investigate the blocking probability of WDM wavelength routed all-optics network with our wavelength routers. (5) Improves an analytical model for light-path blocking performance. The receiver reservation is considered in the light-path requests process with the Markovian correlation model. (6) Compares different Internet routing protocols, OSPF-TE is selected to be routing protocol in ION, And detailedly introduces the principle of RSVP-TE in wavelength convertible optical networks. (7) The requirements of wavelength router implementation are analyzed. Points out the usage of peak band-width, CPU utilization and memory capacity of wavelength router in real-time reservation scene of light-path. (8) A simple all-optical wavelength router is implemented based on ARM7TDMI technology. And the configuration capability, insertion loss, switching time, bit error rate (BER) of the final system are tested.