Bidirectional ring networks have smaller number of hops and fewer wavelengths than unidirectional ring networks. Two fiber bidirectional ring networks utilize fiber more efficiently than 4-fiber bidirectional ring networks. Multi-ring networks using optical cross-connect(OXC) resolve the problem of the increasing number of average hops caused by the increasing number of nodes in networks. These bidirectional WDM networks are required control system which monitors and controls networks.
In this thesis, we implemented control system in 4-node bidirectional WDM ring networks and 5-node bidirectional WDM multi-ring networks using an OXC. In order to implement the control system, it is necessary to implement supervisory channel for communication between each node. We implemented supervisory channel using 1310 nm band. The power margin of supervisory channel is 5 dB. We also implemented control program for networks. Our implemented system continuously monitors not only the status of various network elements and the power of optical signal but also the optical path of each channel.
Our implemented system for 4-node bidirectional WDM ring networks protects networks from link failure within 17 ms, which satisfies SONET requirement of 50 ms. The time for retrieval is 3.5 ms. In 5-node bidirectional WDM multi-ring networks using an OXC, our implemented system protects networks from link failure within 12 ms, which satisfies SONET requirement of 50 ms. The time for retrieval is 2 ms.
From the results it can be shown that multi-ring networks provide faster protection, retrieval, routing and wavelength assignment (RWA) update than single ring networks in the same number of nodes.
