Obs Network Fault Monitoring And Positioning Mechanism

The optical burst switching network(OBS)is a kind of new network architecture,fully transparent for business data.It has no need of any electro-optical transformation and therefore overcomes the difficulty related to electronic bottleneck.The OBS network has become a very good and practical choice for next generation optical networks in the near future.Past research work about OBS network has mostly focused on reservation scheduling,burst assembling,signaling protocol definition and performance analysis,but few on network fault management.In all-optical networks,the signal degradation occurs during transmission in nolo-ideal medium along a light-path.When this degradation reaches a certain level,the signal is no more acceptable.Therefore,we will study here fault management in OBS networks.This paper is structured as following:In chapter 1,we introduced the backgrounds of OBS networks in detail.In chapter 2,the basic principles and structural features of OBS were introduced.In chapter 3,we discussed the protocols of OBS,especially the JET protocol used later.In chapter 4,we studied fault monitoring and localization in OBS networks,as well as the new structures of node model and burst format to support the mechanism.In chapter 5,we improved the routing algorithm based on the JET protocol.In chapter 6,we designed OBS nodes in a simulation platform with OPNET tools.Based on results of the simulation,we analyzed the performance of OBS networks.Points of original innovations in this paper include:1,A new mechanism on fault detection and localization in OBS networks is proposed.New structures of node model and burst format are defined to support the mechanism,and additional bandwidth consumption is minimized by allowing only faulty core nodes to send detection bursts to edge routers.The new localization algorithm can not only localize faults to channel levels,but also estimate what causes these faults.2,A impairment-aware RWA algorithm is proposed in view of previous fault-monitoring information,which takes full consideration of network signal quality and network status,makes data signal bypass faulty nodes and busy locations.It can also recalculate the routing paths in accordance with network changes,thereby reduce effectively the loss rate of data packets,and improve quality of service(QoS)of the whole network.3,We designed a well working platform with OPNET for OBS simulation purposes.