Packet Transport Network (PTN) Protection Mechanism Of Circuit Breaker

China Mobile has a large-scale deployment of operational PacketTransport Network (PTN), which has a unified bearing of2G/3G businesscustomers and LTE test network service in some areas. Because of thehuge PTN bandwidth (usually more than10GE in the convergence layer),it is critical to guarantee the network reliability against circuit break (e.g.fiber cut). Therefore it is very important to implement a protectionmechanism in PTN against circuit break. At present, PTN network ofShanghai Mobile Network mainly uses linear protection based on labelswitched path (LSP). However，as the network is growing larger and larger,linear protection is a vulnerability of the network which may lead tobusiness interruption when multiple failures happen in the underlying fiberring.In this paper, the author analyzes the main features of linear andring protection networks, and proposes a novel protection mechanism forShanghai Mobile PTN network to meet the special requirement of theShanghai Mobile Network upgrade. The proposed protection mechanismintegrates ring network protection in the current deployment of linearprotection structure based on LSP protection. Specifically, the newprotection mechanism adds a ring network protection in the convergencelayer to achieve the purpose of protection against multiple points of failure.The author conducts extensive experiments on actual equipment totest the effectiveness of the proposed protection mechanism. The testresults show that the proposed mechanism can effectively provide reliableservice in the event of multiple faults in the fiber rings. The results alsoverify its feasibility of implementation in large scale networks. Since thisis the first attempt worldwide to implement ring protection in large scale operational network, the results of this paper provide a valuable referencefor network service providers.