Abstract: Efficient transmission and fairness guarantees for upstream traffic in ATM-PONs are achieved using a partial back pressure (PBP) technique for traffic generated from user network interface (UNI) cards, e.g. Ethernet UNI cards or other network interface cards for non-constant bit rate sources. The PBP technique utilizes a feedback flow control mechanism between priority queues and UNI cards in a customer-side interface device, e.g. an Optical Network Termination unit, to achieve improved transmission efficiency and fairness guarantees of incoming traffic. The peak upstream rate of the UNI cards is dynamically controlled based on feedback information from the interface device where a queue status monitor observes the traffic level in the priority queue. Upon reaching a designated threshold level in the priority queue, the status monitor triggers activation of rate controllers in the upstream output of the UNI cards. The rate controllers reduce the peak output of the UNI cards to a controlled peak rate.

Abstract: An optical network has an optical splitter connected to (1) a working optical subscriber unit (OSU) of a working circuit via a working optical fiber, (2) a protection OSU of a protection circuit via a protection optical fiber, and (3) one or more optical network terminals (ONTs), where the protection OSU has a protection burst mode receiver (BMR) configured to receive an upstream optical signal from the optical splitter. The algorithm determines whether the protection OSU is functioning improperly. A reset pulse is applied at the protection BMR at a particular timing position and an attempt is made to interpret the current upstream cell received at the protection BMR. This process is repeated using different timing positions for the BMR reset pulse until the current upstream cell is correctly interpreted, e.g., based on the correct identification of an ATM header error correction (HEC) byte in the upstream cell.

Abstract: An optical network has an optical splitter connected to (1) a working optical subscriber unit (OSU) of a working circuit via a working optical fiber, (2) a protection OSU of a protection circuit via a protection optical fiber, and (3) one or more optical network terminals (ONTs). The present invention enables fast protection switching from the working OSU to the protection OSU. In one embodiment, the arrival times of corresponding upstream ranging reply PLOAM cells are measured at both the working and protection OSUs during ranging operations of the working OSU. In another embodiment, a cell delineation procedure is initiated at the protection OSU during normal, non-ranging operations of the working OSU to enable the protection OSU to correctly delineate upstream cells and the arrival times of corresponding upstream cells are then measured at both the working and protection OSUs.

Abstract: An optical network has an optical splitter connected to (1) a working optical subscriber unit (OSU) of a working circuit, (2) a protection OSU of a protection circuit, and (3) one or more optical network terminals (ONTs), where an ONT has (i) a working line termination (LT) unit of the working circuit and connected to the optical splitter via a working optical fiber and (ii) a protection LT unit of the protection circuit and connected to the optical splitter via a protection optical fiber. The present invention enables fast protection switching from the working circuit to the protection circuit. The arrival times of corresponding downstream cells are measured at both the working and protection LT units of the ONT, and information related to the arrival times is transmitted from the ONT to the protection OSU.

Abstract: Pressure sensing device in a gas furnace including a first tube in communication with a position of an air supply pipe on an inlet side of an air supply fan having a pressure identical to an inlet of the air supply fan, a second tube in communication with a position of an air supply pipe on an outlet side of the air supply fan having a pressure identical to an outlet of the air supply fan, and a pressure difference sensing means respectively connected to the first and second tubes for providing an electric signal according to a pressure difference caused by pressure on the first and the second tubes, thereby detecting clogging states both of the air supply pipe and the exhaust gas pipe, and method for controlling operation of a gas furnace, including the steps of (1) a pressure difference sensing device providing an electric signal according to a pressure difference between inlet/outlet of an air supply fan during operation or a pre-purge step for starting operation, (2) comparing the electric signal to a pre

Abstract: A multi-channel packet switching apparatus having traffic flow controlling and checking functions which is capable of simply controlling the system and having a simpler construction by concurrently performing a cell copy function and a cell routing function for providing a multi-casting function.

Abstract: A fully-interconnected ATM switching apparatus comprising a plurality of line interface circuits, each of the line interface circuits including an input port driver for extracting an SDH transmission frame containing cell data with a fixed length and a connection identifier from an input signal, appending a routing tag to the extracted SDH transmission frame and outputting the resultant SDH transmission frame through an input dedicated bus and an output port driver for receiving a cell stream from an output dedicated bus, removing the routing tag from the received cell stream, translating a channel identifier in the connection identifier and transferring the resultant SDH transmission frame to an adjacent node, a system clock distributor for generating a clock signal, an initialization controller for controlling system initialization and restart operations, a switch maintenance controller for performing a switch maintenance control operation in response to a network managing cell, a switch call processing con

Abstract: The present invention relates to an Asynchronous Transfer Mode (ATM) multi-channel switch with a structure of grouping/trap/routing that, by designating a port as a group, could accept not only the services having higher speed than the speed of input ports, but also the services having super-rate speed by comprising: an input processing unit for executing reading control of externally inputted cells and adjusting synchronization between an externally inputted cell and a cell returned by blocking and feedback; a channel grouping unit for grouping cells outputted from the input processing unit, according to switching control data; a trapping unit for deciding whether cells grouped in the channel grouping means require switching beyond the capacity of the pertinent channel and, if these cells require switching beyond the capacity of the channel, sending them to the input processing unit by feedback; and a routing unit for routing cells outputted from the trapping unit.

Abstract: The present invention relates to a fixed length packet switching apparatus using multiplexers and demultiplexers in which the apparatus has an output buffer-type construction, protects itself from a temporary overflow occurrence of an output terminal and has the construction of the mutual flow control to enhance its entire performance. The present invention can protect the entire operations as well as enhance the entire performance of the switching apparatus by preventing an obstacle of the switching apparatus due to an overflow temporarily generated from an output terminal, process without a loss of excessive cells a traffic phenomenon of one output port in the switching apparatus, reduce the necessary buffer according to the effect of the rate gain and process smoothly input traffic of the internal buffer having a burst characteristic.