Abstract: An apparatus including a network processor and a host system for monitoring packet communications on a packet network. The network processor captures all packets on a link of the network in real-time, to thereby capture communications transmitted via packet on the link. Each communication has at least one corresponding packet media stream. The host system communicates with the network processor to detect the packet media streams from the captured packets and to analyze the detected packet media streams.

Abstract: A host processor operating together with a network processor to detect packet media streams on a link of a packet network in accordance with a trigger. The network processor captures substantially all packets on the link in real-time to thereby capture communications transmitted via packets on the link. Each communication has at least one corresponding packet media stream. The host system communicates with the network processor to detect respective packet media streams from the captured packets in accordance with a trigger.

Abstract: A network device is disclosed. The network device comprises a port to allow reception of a TCAP query. A processor translates the TCAP query into a dial access request and a port allows transmission of the dial access request and to receive a call disposition message.

Abstract: A method for generating speech packets and a communication apparatus implementing the method and functioning as a first node of a communication system. A first stream of digital speech samples having a first sample rate is provided (201). If the first sample rate is determined (202) as not matching a required sample rate, said speech packets are generated (204) based on a second stream of digital speech samples generated (203) by performing sample rate conversion of the first stream of digital speech samples.

Abstract: An exemplary mechanism for intelligent Point-to-Point Protocol over Ethernet (PPPoE) initialization is disclosed herein. During the PPPoE discovery stage, a PPPoE client of a CPE determines the status of a connection between the CPE and an access concentrator prior to transmitting a PADI and/or PADR packet. If a physical layer connection is established, the PPPoE client can provide the packet to the physical interface for transmission to the access concentrator. If a physical layer connection is not established, the PPPoE client either periodically rechecks the status of the connection until a physical layer connection is established or the PPPoE can terminate the PPPoE discovery stage after a certain number of iterations. Additionally, prior to waiting for a PADO or PADS packet, the PPPoE client can be adapted to check the status of the connection. If a physical layer connection exists, the PPPoE client can initiate the wait for the packet.

Abstract: A method of routing traffic in a switch includes forming an optimized routing table specifying for each switch ingress port an exit port to be utilized to reach a specified destination domain. The optimized routing table is formed in accordance with load distribution, oversubscription, and fragmentation criteria. The optimized routing table is distributed to a set of ingress ports of the switch.

Abstract: A set-up scheme for a cut-through connection in a network system capable of realizing a high throughput, low latency internetwork communication efficiently under an internet environment. A network node checks source/destination information of the transport layer and/or a source/destination information of the network layer of a received packet, and if the checked information satisfies a prescribed condition, determines the packet to be a trigger. Then, the network node instructs another node capable of initiating a set-up operation, which may be the network node itself, to initiate the set-up of the cut-through connection for traffic corresponding to the trigger packet.

Abstract: The invention relates to a message transfer device and to a method for transferring messages comprising at least one group header field, which allows a differentiated classification by extension of the value range of the group header field and/or evaluation of another group header field.

Abstract: The present invention relates to a method of forwarding multicast message in network communication. In the method: first, configure forwarding match condition at the entry interface to the network device requiring forwarding multicast message, the forwarding match condition regulates forwarding rule for the multicast message; then, match the multicast message to be forwarded to network device through the interface with the forwarding match condition, and forward the multicast message according to the matching result. The present invention can configure the sending mode of messages according to requirement and can effectively avoid risks in security that may be caused by the broadcast mode for the multicast messages in the link layer as well as efficiency loss caused by receiving a great deal of invalid multicast messages, and the configuration is simple, and more convenient use and management is realized.

Abstract: A cell multiplexing apparatus comprising call monitors and multiplexers. The call monitors monitor a plurality of channels for their call setting status and select at least two channels for which the same cell may be assembled, i.e., for which the destination of the calls is the same. The multiplexers receive audio information or information already assembled in asynchronous transfer mode (ATM) cells from the channels selected by the call monitors, and disassemble and multiplex the received information for assembly into the payload of a new ATM cell.

Abstract: A method of administering network performance data comprises the steps of parsing a cell to obtain a stream identifier and calculating network performance data from information in the cell. The method further comprises storing the stream identifier in a content addressable memory (CAM) at a next available address in the CAM and storing the network performance data in a network performance data memory element at an address in the network data memory element that is related to a value of the next available address in the CAM. The process further comprises the steps of obtaining an irrelevant CAM address wherein an entry at the irrelevant CAM address contains a value matching the stream identifier of an irrelevant stream. The process stores a value at the irrelevant CAM address of a sum of the stream identifier and a mask value. The mask value temporarily prevents use of the irrelevant CAM address during a memory element administration process.

Abstract: In one embodiment, a protocol option is implemented in which a network packet stores a maximum transmission unit size to use for sending data on a path between a sender and a recipient. The stored value is replaced if a receiver of the network packet uses a maximum transmission unit (MTU) smaller than the stored value. The option may be used in an initiation packet sent during a communication initiation handshake to allow both establishment of a communication session as well as determination of an efficient transmission unit size. The initiation packet may be sent with a do-not-fragment option set so that if a receiver does not understand the option, and the packet is too large for the receiver, then receiver will reject the packet and place the sender on notice that a conventional trial-and-error approach is required to determine an allowable MTU.

Abstract: An Enhanced Service Layer Mapping which is hierarchical and widely load balanced to derive an efficiently distributed architecture. At the top of the hierarchy, all the ports are grouped into SPG units and tightly coupled with the SSS unit. At the second level of the hierarchy, within a given SPG-SSS unit, the ports and subscribers are sub-grouped and tied to a sub-pool of PEs. At an even lower level of the hierarchy, subscribers and services are mapped and load balanced to a fixed PEs.

Abstract: A reliable packet communication device capable of flexibly adding new functions. A packet communication device is composed of multiple interface elements (IFEs), switching elements (SWE) connecting these IFEs, and a routing manager element (RME) and may also if necessary comprise special functional packet processors (xFPs) capable of different special functions. The interface element and special functional packet processor are connected by a logical bus. For the purpose of connecting the interface elements and special functional packet processors through the switching element when the logical bus has a failure, the logical bus data format is made identical to the data format for passing data through the switch element and a selection circuit is installed in the interface element for selectively sending and receiving data to/from either the logical bus or the switching element.

Abstract: In a multiplexing apparatus, input data sequences of two types a and b are packetized using fixed lengths La and Lb so as to produce packets 3a and 3b, respectively. A flag 1 and headers 2a and 2b indicating a data type of packet are attached to the packets 3a and 3b for transmission. In a demultiplexing apparatus, when the header 2 cannot be properly identified due to a transmission error or the like, subsequent demultiplexing steps are performed by estimating that the subsequent data is the input data sequence a, when the length La occurs before the next flag 1, and estimating that the subsequent data is the input data sequence b, when the length Lb occurs.

Abstract: A method and distributed scheduler for use therewith has at least two clusters of source port modules, each tracking all queues associated with a respective input-node and relating to a respective subset of available input-nodes. Each source port module receives available output-nodes, and generates a weight for each queue therein. Each source port module generates at least one request relating to the highest weight serviceable queue. The respective requests of each source port module are accumulated, and for each cluster of source port modules, the request is chosen for which no two requests relate to the same input-node, and for each output-node, the chosen requests have highest weight. The highest weight request from all clusters is determined in respect of each output node receiving requests from one or more input nodes. A grant is sent to the input-node having the highest weight request.

Abstract: UBR traffic control apparatus and methods can control UBR bandwidth according to cell traffic state and congestion occurrence at the switch terminal. Preferred embodiments can include an egress subscriber terminal that monitors congestion of cells at the switch terminal and traffic state to generate UBR bandwidth information, and an ingress subscriber terminal that outputs UBR cells to the switch terminal according to the generated UBR bandwidth information. Preferred embodiments can increase or maximize UBR traffic by flexibly increasing, decreasing or maintaining UBR bandwidth in consideration of the cells' congestion experience at the switch terminal, the egress subscriber terminal's buffer threshold value and traffic load. By managing cell traffic state for each transmitting subscriber board and by determining subscriber boards to be controlled in consideration of the traffic state at the time of UBR bandwidth's increase or decrease, the preferred embodiments may improve the quality of UBR service.

Abstract: Jitter and time delays during the transmission of payload packets via a packet-switched data network are avoided by means of a device and a method for transmitting payload packets (1, 2, 3, 4) in a packet-switched network (9), wherein payload packets (1, 2, 3) on their path (14, 19, 17, 20) through the data network (9) are combined (11) on a number of occasions to form a group packet (5) which is to be transmitted along part (14) of the path. After the group packet (5) has been transmitted (14) along part (14) of the path, said payload packets are individually processed (15, 19, 16, 17, 18, 20). The time information (12,13) which is to be transmitted in a group packet (5) is used to reestablish (15) the time delay of payload packets (1, 2, 3) in relation to each other.

Abstract: The present invention provides an emergent network that is autonomous at the service level. Network nodes have policies that enable them to process different types of service requests, with the processing earning the nodes ‘rewards’. Successful nodes can pass some or all of their policies to other nodes using the evolutionary biology of bacteria as a model. The network is arranged into clusters of nodes, with unprocessed service requests being passed from cluster to cluster.

Abstract: A non-IP device holds an interface ID defined by Ipv6. A gateway generates and holds an Ipv6 address for the non-IP device. The gateway serves to convert the protocol of a packet destined to the non-IP device from a portable telephone or a personal computer coupled to an internet into the protocol for a network connected to the non-IP device and transmit the packet to the non-IP device.

Abstract: There are provided an apparatus and method for transmitting data in a network system using network address translation. The method for transmitting data includes the steps of receiving a global network address corresponding to a local network address from a router using network address translation; encoding data using the global network address; and transmitting the encoded data to an external host on the global network via the router. Since the network address to be translated through the network address translation can be anticipated and substituted in real time during the transmission of the data, a variety of security services can be provided without significant modifications to the existing system, and accordingly, it is anticipated that the Internet protocol version 6 can be increasingly used.

Abstract: In a communication network including at least one user associated with a plurality of terminals, a method of administering information associated with at least one user and/or the plurality of terminals, the method comprising: transmitting to a server a first message from a first terminal of the at least one user, the first message comprising message information and an identifier of the first terminal; and transmitting a second message including at least part of said message information from the server to at least one of only the other terminals of the user.

Abstract: One embodiment of the present invention provides a control queue for an asynchronous circuit that includes a number of control modules coupled together linearly to form the control queue. These control modules include a prior module, a present module, and a next module. The present module is configured to receive one or more forward-going inputs from the prior module and one or more reverse-going inputs from the next module. The present module asynchronously generates one or more forward-going outputs to the next module and one or more reserve-going outputs to the prior module. The modules within the control queue are constructed so that the latency of the forward-going signals through the control queue is equal to the latency of the reverse-going signals through the control queue.

Abstract: A network processor that has multiple processing elements, each supporting multiple simultaneous program threads with access to shared resources in an interface. Packet data is received from high-speed ports in segments and each segment is assigned to one of the program threads. Each packet may be assigned to a single program thread, two program threads—one for header segment processing and the other for handling payload segment(s)—or a different program thread for segment of data in a packet. Dedicated inputs for ready status and sequence numbers provide assistance needed for receiving the packet data over a high speed port. The dedicated inputs are used to monitor ready flags from the high speed ports on a cycle-by-cycle basis. The sequence numbers are used by the assigned threads to maintain ordering of segments within a packet, as well as to order the writes of the complete packets to transmit queues.

Abstract: Communications in a wireless communication system based on two or more communication standards are configured for delivery to cell sites or to subscribers using a digital link having channels assigned to the two or more communication standards. A T-1 level can be divided into twenty four channels that are assigned to two or more mobile standards, and subscriber or network communications based on the two or more standards can be delivered to, for example, radio transmitters associated with the mobile standards. Channel allocation can be revised based upon requested capacity associated with the mobile standards.

Abstract: A technique that enables a shared communications medium to achieve an increased data rate under lossy conditions while maintaining low latency is disclosed. The technique incorporates two aspects that enable the improved performance. The first aspect comprises the rigorous use of a single message flow between two stations at any given time with interframe spaces that are adjusted to allow an uninterrupted flow of frames. An admission control protocol enforces the single flow. The second aspect is the creation of high shared channel utilization (i.e., “efficiency”). Efficiency is achieved by generating enough opportunities for stations to get on the air, in part by minimizing backoff intervals when a priority flow is needed.

Abstract: A polling loop system provides all products to be prewired to the polling loop by technically unskilled labor followed by a plug and play enrollment process. The system combines the advantages of DIP switch zone addressing with smart serial number (S/N) addressing, which simplifies installation and replacement requirements. The system is fully backward compatible and is intended for a next generation of commercial polling loop systems.

Abstract: The invention relates to a device and to a method for the packet-based access of classical ISDN/PSTN subscribers to a switching system. The convergence of packet-based networks and TDM networks leads to a situation where classical analogous and ISDN subscribers and private branch exchanges have to be accessed via packet-based transmission methods. Especially for the case of a failure of, for example, the subscriber terminals TNE or switching system-related devices or intervening communication paths, it must be made sure that substitute connections can be made and stable connections can be maintained. This problem is solved by the present invention by providing a peripheral adaptation device, integrated into the periphery of the switching system, and being suitable for the adaptation of the messages used on the interface between subscriber terminal and peripheral adaptation device, to the requirements of the plurality of peripheral devices associated with the TNE port.

Abstract: A system for transmitting subchannel data over the same media as high speed data, especially DC balanced high speed data. A digital transmitter receives subchannel data and modulates it onto a subchannel carrier as the host signal in the preferred embodiment using frequency shift keying. The FSK subchannel carrier is added by superposition to the high speed data signal. At the receiver, a low pass filter filters out the subchannel carrier frequency components which are then amplified and subjected to a two-pole anti-aliasing filter to remove the third and fifth harmonics. Analog-to-digital conversion is followed by a digital mix down to remove the subchannel carrier component using a local oscillator at the subchannel carrier frequency. An FIR low pass filter having a triangular time domain response performs anti-aliasing and leaves as an output only frequency components at the positive and negative deviation frequency for Mark and Space.

Abstract: Systems and techniques are disclosed relating to communications. The systems and techniques involve communicating over a physical channel having a plurality of modulation channels each having a channel capacity by allocating a plurality of data streams among the modulation channels as a function of the channel capacity for each of the modulation channels, and modulating the data streams to support transmission over the physical channel as a function of the data stream allocation among the modulation channels. It is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

Abstract: A method for operating a device (such as a printer) having a first interface (such as USB interface) connectable to a first computer and a second interface (such as an Ethernet interface) connectable to a second computer. A phase lock loop (PLL) circuit is obtained which is driven by a clock source, which is adapted for switching between operating at the first and second clock frequencies, and which is operatively connected to the first and second interfaces to provide a clock signal to the first and second interfaces. The PLL circuit is operated at the first clock frequency when the first interface is active and is operated at the second clock frequency when the second interface is active. A device includes the first and second interfaces, the PLL circuit, and the clock source.

Abstract: Disclosed is a wavelength division multiplexing optical switching system, which is connected with a plurality of nodes of an optical network and supports communication between the nodes. The optical switching system includes a wavelength division demultiplexing unit which demultiplexes optical signals received from each of the plurality of nodes and outputs them as channels with different wavelengths. A routing unit which classifies the channels in accordance with destinations thereof. A fixed wavelength converting unit which converts the classified channels into channels of a single wavelength, the single wavelength being allocated in accordance with corresponding starting places. A wavelength division multiplexing unit which collects the wavelength-converted channels in accordance with destinations and then outputs them as multiplexed optical signals.

Abstract: A factory-side system having at least one semiconductor processing system, and a vendor-side system owned by an administrator who manages the maintenance of the semiconductor processing system are connected to each other through a bidirectional network. The factory-side system stores a allowable limit value of operation time of a preset part, measures actual operation time of the part, compares the actual operation time and the allowable limit value with each other to judge the operation state of the part, and sends an order processing request of the part to the vendor-side system through the network in accordance with a result of the judgement. If the vendor-side system receives the order processing request of the part, the vendor-side system carries out the order processing of the part. With this, it is possible to prevent trouble, accident and the like of the part.

Abstract: A method and apparatus are provided for scaling an input bandwidth for bandwidth allocation technology. An original bandwidth count value of an input flow is received. A bandwidth scaler constant is provided and used for scaling the received original bandwidth count value to provide a scaled bandwidth value between zero and one. The scaled bandwidth value is stored and used for calculating a transmit probability for the input flow.

Abstract: A method (30) schedules the utilization of the supplemental channel of a base station transceiver (20-25). This scheduling includes time slot assignment as well as data transfer rate per time slot. One method simply selects the next time slot with a maximum rate for the primary base station transceiver (130). The method then selects the same time slot for each of the secondary links with the secondary base stations (132). The data is then simply sent to each of the BTSs (20-25) for transmission to the mobile station (10). In another alternative, a request is made for a supplemental channel usage for the primary link (144). Then secondary links are selected for transmission to the mobile station (10) only if they provide additional diversity gain (148) and resources are available at the secondary link BTSs.

Abstract: Methods and apparatus detecting attempts to obtain IP addresses by faking a MAC address in a data portion of an IP address request message are described. In accordance with the present invention, rather than use standard address allocation protocols, e.g., ARP, the DNS DCHP contacts the requesting edge router via a private secure network. The MAC address received in the address request is compared to the MAC addresses stored in the edge routers port/MAC address resolution table. If the MAC address received in the request message cannot be found in the edge router's table which was created from the MAC address included in the message's header, a fraudulent attempt to obtain a MAC address is declared. The fraudulent attempt to obtain an IP address can be reported and steps taken to identify the perpetrator of the fraud.

Abstract: ADSL systems with hybrid FDD/TDD duplexing using a hyperframe of mixtures of upstream-downstream FDD frames and all downstream frames.

Abstract: A process of generating an inter-packet gap in a network device is disclosed. First, it is determined whether a next packet is available to forward from a packet buffer. The number of tokens contained in a token bucket is checked and bytes are added to the inter-packet gap and tokens are added to the token bucket, when the number of tokens contained in a token bucket is less than a predetermined number of tokens. Otherwise, the size of the inter-packet gap is reduced and tokens are taken out of the token bucket, when the number of tokens contained in a token bucket is greater than or equal to the predetermined number of tokens. Thereafter, the inter-packet gap is supplied and sent with the next packet over an interface between the network device and a network.

Abstract: A method and apparatus to de-multiplex a de-interleaved frame is provided. The method of de-multiplexing may add a de-interleaved address of a symbol of the de-interleaved frame to a base address of the de-interleaved frame to provide a target address. The symbol may be written in a channel buffer according to the target address.

Abstract: A method and system for network timing recovery that recovers the timing reference by multiplying an 8 kHz reference clock up to one of a number of higher frequencies whilst maintaining phase alignment. Further, the present invention allows the 8 kHz reference signal to be generated from a software controlled frequency generator where no external reference is available. It also provides a configuration whereby the choice of external or internal 8 kHz reference is controlled by software, and further than said 8 kHz reference is always used as the input to the phase locked loop (PLL) clock multiplier. An algorithm to control the internal 8 kHz generator will not require to take into account “phase jumps” where the frequency suddenly changes by a large amount by passing the generated 8 kHz clock through the phase locked loop (PLL), where any large phase increase or decrease on the input clock will be filtered out and not passed though directly to the multiplied clock output.

Abstract: A command synchronization establishment system using a network wherein data is transferred by an isochroous transfer, a command is transferred by an asynchronous transfer, and a synchronized clock is shared by apparatuses connected to the network, the system comprising a controller connected to the network, comprising a transmitter that transmits a command including a time-stamp to a target apparatus by using the asynchronous transfer, and the target apparatus connected to the network, comprising a receiver that receives the command, a storage device that temporally stores the received command in order not to execute the received command instantly, and a executing device that executes the received command in accordance with the time-stamp included in the command to be executed.

Abstract: A receiving terminal 2 calculates jitter moving average from the transmission and the reception time of each packet and sends the moving average to a transmitting terminal 1, and based on the jitter moving average, the transmitting terminal predicts an available bandwidth in a radio path.

Abstract: A multiple bit stream interface interfaces a first transmit data multiplexing integrated circuit and a second transmit data multiplexing integrated circuit. The multiple bit stream interface includes an interface plurality of transmit bit streams each of which carries a respective bit stream at an interface bit rate and in a natural order. The interface further includes a transmit data clock operating at a frequency corresponding to one-half of the interface bit rate. The first transmit data multiplexing integrated circuit receives a first plurality of transmit bit streams from a communication ASIC at a first bit rate. The second transmit data multiplexing integrated circuit produces a single bit stream output at a line bit rate. The interface plurality of transmit bit streams is divided into a first group and a second group, wherein the first group is carried on first group of lines and the second group is carried on a second group of lines.

Abstract: An arrangement and method for channel mapping in a UTRA TDD HSDPA wireless communication system by applying interleaving functions in first (530) and second (540) interleaving means to a bit sequence to produce symbols for mapping to physical channels, the first and second interleaving means being arranged to map symbols from respectively systematic and parity bits in a predetermined scheme, e.g., mapping symbols in a forward direction when a channel has an even index number, and in a reverse direction when a channel has an odd index number. The symbols may comprise bit-pairs, each of a systematic bit and parity bit. Systematic bits are preferably mapped to high reliability bit positions in TDD HSDPA, achieving a performance gain of between 0.2 dB and 0.5 dB. The forwards/reverse mapping allows a degree of interleaving that improves system performance in fading channels or channels disturbed by short time period noise or interference.

Abstract: System and method for detection of mode hops in the output of continuously tunable lasers according to variation in the period of an interference signal derived from laser output. The method comprises generating an interference signal from laser output, detecting variation in the period of the interference signal, and determining the presence of a mode hop or mode hops from the detected variation in the period of the interference signal. The methods may additionally comprise adjusting the cavity of the laser when a mode hop is detected.

Abstract: There is provided a semiconductor laser device containing a laser driver capable of implementing downsizing, thinning and cost reduction of equipment using the laser device. In the semiconductor laser device containing a laser driver, a semiconductor laser element, a laser driver for driving the laser element, and a signal detection part for performing photoelectric conversion are mounted on a common mount surface of a lead frame and moreover accommodated in a common package. Upward of the semiconductor laser element is provided a hologram element for transmitting laser light emitted by the laser element toward a recording medium and then diffracting toward the signal detection part the laser light reflected by the recording medium. The laser driver and the signal detection part are disposed on both sides with respect to an optical axis of the laser element.

Abstract: In a semiconductor laser device, a flange (33) of a cap (32) is provided with straight-line cut-off portions (34) that are the same in number as notches (36, 37) of a stem (35). With the cut-off portions (34) positioned so as not to overlap the notches (36, 37) of the stem (35) in position, welding between the cap (32) and the stem (35) is performed. The cut-off portions (34) of the cap (32) secure obtainment of a reference plane 38 with a large area in a place where the notches (36, 37) of the stem (35) are absent. As a result, sufficient precision in optical characteristics can be secured while suppressing an influence of unevenness of the stem (35) having a small diameter on a deviation angle &thgr; of an optical axis from a normal line to a reference plane of an optical pickup.

Abstract: A method for manufacturing a semiconductor laser device, comprising the steps of: forming an electrode pattern on an upper surface of a semiconductor wafer stacked at least a light emission layer; cutting the resultant semiconductor wafer for predetermined width to yield a plurality of semiconductor bars; and sectioning the semiconductor bars into a desired size to form semiconductor laser devices having a pair of cleavage surfaces which are parallel to a chip-width direction and distant from each other by a predetermined resonator length, wherein the electrode pattern formed in the step of forming an electrode pattern is continuous at least in a resonator-length direction.

Abstract: A gas discharge laser having an elongated cathode and an elongated anode with a porous insulating layer covering the anode discharge surface. A pulse power system provides electrical pulses at rates of at least 1 KHz. A blower circulates laser gas between the electrodes at speeds of at least 5 m/s and a heat exchanger is provided to remove heat produced by the blower and the discharges. In preferred embodiments at least a portion of the anode is comprised of lead, and fluorine ion sputtering of the anode surface creates the insulating layer (over the discharge surface of the anode) comprised in large part of lead fluoride. In a particular preferred embodiment the anode is fabricated in two parts, a first part having the general shape of a prior art anode with a trench shaped cavity at the top and a second part comprised of lead rich brass and disposed in the trench shape cavity.

Abstract: Electrodes for a fluorine gas discharge laser are disclosed which may comprise a crown straddling the centerline axis between the pair of side walls and the pair of end walls, comprising a first material, forming at least a portion of the discharge region of the electrode; the crown in traverse cross section having the shape of the upper half of a canted ellipse rotated in the preionizer direction, such that a tangent to the short centerline axis of the ellipse forms an angle with the horizontal. Another embodiment may comprise an anode blade having a top portion and a first and second sidewall portion each intersecting the top portion; the anode blade being formed with the shape in cross section of the top portion being curvilinear and intersecting the generally straight potions of each of first and second sidewall portions along a radius of curvature and with the top portion beveled away from an asymmetric discharge side of the anode.