Abstract: Ethernet packets are transmitted in full duplex mode over a single coaxial cable, such as RG6 and RG59. Symmetrical full duplex operation is achieved by separating the upstream and downstream signals in the frequency domain whereby a 100BaseT signal is transmitted unmodified in one direction while the other is modulated upon a high frequency carrier to be transmitted in the other direction. In a second embodiment, the separation is in the time domain whereby the signals are sampled in blocks, each block compressed in time and transmitted at a higher rate, thus allowing for the interleaving of upstream and downstream blocks on the same coaxial cable. In a third embodiment, different rate upstream and downstream signals are separated in the frequency domain, but without modulation. The resulting asymmetrical 1000/100 Mb/s Ethernet over coax link is valuable in network architectures where asymmetry in the up and down traffic loads is expected.

Abstract: This invention provides a method for commissioning an optical network using internal Automatic Spontaneous Emission (ASE) light inherently present in the optical network as a light source (the ASE light source) for measuring losses inside and between nodes in the network. A modular segmented approach is adopted and the network is commissioned segment by segment. The method uses techniques for the correction of the Optical Signal to Noise Ratio induced error as well as the Spectral Filtering Error during the loss computation required for adjusting the gains of the amplifiers at each network node to an appropriate value. Since the method does not require an external laser source that needs to be moved manually from node to node, it greatly reduces the commissioning time. Since it uses only the existing components of the network nodes it also leads to a significant saving in cost.

Abstract: A multi-stage method and apparatus for determining a faulty component location along an optical path through an optical fiber in an optical network are disclosed. The optical fiber carries a plurality of wavelengths, which may or may not be modulated by low frequency dither tones that are utilized for identification purposes and performance monitoring in the optical network. First, the method comprises measuring a total power of the optical fiber and a total wavelength power as a sum of powers of the individual wavelengths at a plurality of local detection points; comparing the measured powers at the local detection points; and determining whether or not a faulty detection point exists along the optical path. If a fault is identified, the method further provides a multi-stage fault detection procedure, which comprises measuring a total wavelength power loss between a local detection point and an adjacent detection point, between the local detection point and multiple non-adjacent detection points.

Abstract: A failure protection between interconnected adjacent Resilient Packet Rings (RPRS) in a multiple RPR network is provided. Two paths, a regular message path and a protection path, are provided between two adjacent RPRs. The regular path is used for routing inter-ring messages when no failure has occurred on the path. Messages are rerouted through the protection path when a failure occurs on the regular path. Each of these paths has two RPR interface nodes (one for each RPR) that are connected to an interconnection device (a layer 2 bridge or a layer-3 router) through interconnection links. Procedures for detecting failures and generating notifications for message rerouting and fault reports are executed at the interconnection devices. The procedures use periodic keep alive messages for diagnosing network segment and interconnection device failures. The fault detection and message rerouting are accomplished in less than 50 ms.