Abstract: A method for controlling the flows of data packets that are switched or routed at nodes of high-speed communication networks is disclosed. According to the invention, resource metering units are assigned to resources shared between devices of the switch or router e.g., shared memories or link bandwidths. When the occupancy of a shared resource reaches a predetermined threshold, an event is generated and transmitted to devices sharing this resource. Furthermore, a periodic refresh of the overall flow control information is performed so that lost events are, however, eventually acted on. Thus, a new device may become active without perturbing the active flows after having gathered enough flow control information.

Abstract: A high speed data packet switch comprising input and output ports and a switch fabric to link each input port to each output port wherein each connection between input and output ports comprises a dynamic buffer memory for storing at least one data packet for a minimum specified storing time is disclosed. When a data packet is received through an input port, it is written in all individual dynamic memory buffers connected to this input port so as to have a copy of the incoming data packet ready to go through any output port to support unicast, multicast and broadcast traffic. Given the architecture of the data packet switch and its control algorithm, dynamic memory buffers neither need to be refreshed nor their contents have to be restored after reading.

Abstract: A high speed data packet switch comprising input and output ports and a switch fabric to link each input port to each output port wherein each connection between input and output ports comprises a dynamic buffer memory for storing at least one data packet for a minimum specified storing time is disclosed. When a data packet is received through an input port, it is written in all individual dynamic memory buffers connected to this input port so as to have a copy of the incoming data packet ready to go through any output port to support unicast, multicast and broadcast traffic. Given the architecture of the data packet switch and its control algorithm, dynamic memory buffers neither need to be refreshed nor their contents have to be restored after reading.

Abstract: A method for combining a simple forward error correction code i.e., a Hamming-like code with scrambling and descrambling functions is disclosed. Therefore, irrespective of the information to be transported, received data may be corrected, bit error spreading effects being handled, while providing desirable signal characteristics such as signal DC balance and enough signal transitions. The overhead introduced by the method is a modest increase over the original overhead of the 10 Gb Ethernet 64B/66B code.

Abstract: A method and apparatus for performing encoding and decoding of bit chain data packets conveying errors which do not spread on more than n bits, at very high speed. In one embodiment, a matrix of the corresponding Systematic code is built using p×p matrix blocks comprising elements of a galois field, generated by an irreducible generator polynomial of degree p, p being greater or equal to n.

Abstract: The present invention describes direct decoding of Error Correction Codes (ECC) such as, for example, FIRE and similar codes, and detecting and correcting errors occurring in burst, without requiring any pattern shift or sequential logic. According to the present invention, the syndrome of a code generated with a degree-d polynomial is split into sub-syndromes that are combined to form at least one kind of error pattern from which an error pattern is picked. If the picked error pattern does not correspond to an uncorrectable error and errors are not confined within first d bits, one of the sub-syndromes is selected according to the correction mode. The ranks of this selected sub-syndrome and picked error pattern in the Galois field generated by a factor of the degree-d polynomial are determined.

Abstract: The present invention discloses CRC checking ‘N-bit at a time’ of data frames of lengths not necessarily in a multiple of the N-bit. While receiving the data frame, the data frame length is extracted from the protocol header and a misalignment is computed versus the ‘N-bit at a time’ value. Simultaneously, CRC is computed on each received N-bit of the data frame and an FCS register is updated. At each cycle, a checking is performed to know whether the data frame length has been extracted from the protocol header. While the data frame length is not yet known and more bits are left to process, the data frame is continued to be received and computed ‘N-bit at a time’. When the data frame length is known and no more bits are to be processed, the current value of the FCS register is compared to a pre-stored vector corresponding to the misalignment. If a match occurs, checking of the data frame passes and the data frame is accepted.

Abstract: A backplane system allowing a very large number of interconnections between high-connectivity printed circuit boards and a backplane is disclosed. The backplane is fragmented into a plurality of backplane parts that comprise connectors on their edges to mate connectors arranged on the high-connectivity printed circuit boards. These backplane parts may also include other connectors on their edges to couple to extension printed circuit boards requiring less interconnections or cables. Interposers can be used to link several backplane parts and provide enhanced air circulation.

Abstract: A method and a system to adapt the load balancing of the incoming traffic over the planes of a parallel packet switch (PPS) on the basis of the monitoring of requests and acknowledgments exchanged between ingress port adapters and arrays of collapsed virtual output queues (cVOQ) situated within the plane switch cores is disclosed. According to the invention, at least one counter is associated, in each ingress port-adapter, to each individual switching plane or device to be monitored. Each of these counters is incremented when a request is sent to the corresponding individual switching plane or device and decremented when an acknowledgment is received from this individual switching plane or device. When the range of values taken by the counters of a same ingress port-adapter reaches a predetermined threshold, less (or none) incoming traffic is further transmitted to the individual switching plane or device associated to the higher value counter. An alarm signal is possibly raised too e.g.

Abstract: A method for selecting packets to be switched in a collapsed virtual output queuing array (cVOQ) switch core, using a request/acknowledge mechanism. According to the method, an efficient set of virtual output queues (at most one virtual output queue per ingress adapter) is selected, while keeping the algorithm simple enough to allow its implementation in fast state machines. For determining a set of virtual output queues that are each authorized to send a packet, the algorithm is based upon degrees of freedom characterizing states of ingress and egress adapters. For example, the degree of freedom, derived from the collapsed virtual output queuing array, could represent the number of egress ports to which an ingress port may send packet, or the number of ingress ports from which an egress port may receive packets, at a given time.

Abstract: A system and a method to avoid packet traffic congestion in a shared-memory switch core, while dramatically reducing the amount of shared memory in the switch core and the associated egress buffers, is disclosed. According to the invention, the virtual output queuing (VOQ) of all ingress adapters of a packet switch fabric are collapsed into its central switch core to allow an efficient flow control. The transmission of packets from an ingress buffer to the switch core is subject to a mechanism of request/acknowledgment. Therefore, a packet is transmitted from a virtual output queue to the shared-memory switch core only if the switch core can actually forward it to the corresponding egress buffer. A token based mechanism allows the switch core to determine the egress buffer's level of occupation. Therefore, since the switch core knows the states of the input and output adapters, it is able to optimize packet switching and to avoid packet congestion.

Abstract: A backplane system allowing a very large number of interconnections between high-connectivity printed circuit boards and a backplane is disclosed. The backplane is fragmented into a plurality of backplane parts that comprise connectors on their edges to mate connectors arranged on the high-connectivity printed circuit boards. These backplane parts may also include other connectors on their edges to couple to extension printed circuit boards requiring less interconnections or cables. Interposers can be used to link several backplane parts and provide enhanced air circulation.

Abstract: A system and a method to avoid packet traffic congestion in a shared memory switch core, while dramatically reducing the amount of shared memory in the switch core and the associated egress buffers and handling unicast as well as multicast traffic. According to the invention, the virtual output queuing (VOQ) of all ingress adapters of a packet switch fabric are collapsed into its central switch core to allow an efficient flow control. The transmission of data packets from an ingress buffer to the switch core is subject to a mechanism of request/acknowledgment. Therefore, a packet is transmitted from a virtual output queue to the memory shared switch core only if the switch core can send it to the corresponding egress buffer. A token based mechanism allows the switch core to determine the egress buffer's level of occupation. Therefore, since the switch core knows the states of the input and output adapters, it is able to optimize packet switching and to avoid packet congestion.

Abstract: A backplane system allowing a very large number of interconnections between high-connectivity printed circuit boards and a backplane is disclosed. The backplane is fragmented into a plurality of backplane parts that comprise connectors on their edges to mate connectors arranged on the high-connectivity printed circuit boards. These backplane parts may also include other connectors on their edges to couple to extension printed circuit boards requiring less interconnections or cables. Interposers can be used to link several backplane parts and provide enhanced air circulation.

Abstract: A method for combining a simple forward error correction code i.e., a Hamming-like code with scrambling and descrambling functions is disclosed. Therefore, irrespective of the information to be transported, received data may be corrected, bit error spreading effects being handled, while providing desirable signal characteristics such as signal DC balance and enough signal transitions. The overhead introduced by the method is a modest increase over the original overhead of the 10 Gb Ethernet 64B/66B code.

Abstract: A system for controlling egress buffer saturation includes, for each data packet flow, a comparator for comparing the number of data packets ‘WPC’ temporarily stored within an egress buffer to a predefined threshold value ‘WPCth’. The packet sequence number ‘PSNr’ of a last received in-sequence data packet and each highest packet sequence number ‘HPSNj’ received through respective ones of the plurality of switching planes is stored. By comparing the last received in-sequence packet sequence number ‘PSNr’ to each highest packet sequence number ‘HPSNj’ when the number of data packets ‘WPC’ exceeds the predefined threshold value ‘WPCth’ a determination as to which switching plane(s), among the plurality of switching planes, to unstop the flow of data packets can be made.

Abstract: In a network device packets are marked with sequence identifiers at ingress of said device, switched through a plurality of switching planes and re-sequence on a per flow basis at egress of the device. The re-sequencing system includes a controller that allocates to each received data packet a temporary storage location in a packet buffer. A plurality of output registers are providers with one of each being associated with a flow. A pointer uses predefined parameters to point to an output register that has been previously assigned to a flow corresponding to each received data packet. Parameters in the pointed output register are correlated with parameters in a received packet to determine if the received packet is next in sequence to packets process through a particular queue.

Abstract: A method to resequence packets includes sequentially allocating in each source ingress adapter a packet rank to each packet received within each source ingress adapter. In each destination egress adapter, each ranked data packet is stored at a respective buffer address of an egress buffer. The respective buffer addresses of data packets received by a same source ingress adapter with a same priority level and switched through a same switching plane are linked in a same linked-list. The respective buffer addresses are preferably linked by their order of use in the egress buffer, and thus each linked-list is having a head list pointing to the oldest buffer address. The linked-lists are sorted into subsets including those linked-lists linking the respective buffer addresses of data packets received by a same source ingress adapter with a same priority level.

Abstract: A system for resequencing data packets is disclosed. In a preferred embodiment, the system operates in a parallel packet switch architecture having at least one egress adapter arranged to receive data packets issued from a plurality of ingress adapters and switched through a plurality of independent switching planes. Each received data packet belongs to one sequence of data packets among a plurality of sequences where the data packets are numbered with a packet sequence number (PSN) assigned according to at least a priority level of the data packet. Each data packet received by the at least one egress adapter is further having a source identifier to identify the ingress adapter from which it is issued. The system for restoring the sequences of the received data packets operates within the egress adapter and comprises buffer for temporarily storing each received data packet at an allocated packet buffer location.

Abstract: A method for controlling the flows of data packets that are switched or routed at nodes of high-speed communication networks is disclosed. According to the invention, resource metering units are assigned to resources shared between devices of the switch or router e.g., shared memories or link bandwidths. When the occupancy of a shared resource reaches a predetermined threshold, an event is generated and transmitted to devices sharing this resource. Furthermore, a periodic refresh of the overall flow control information is performed so that lost events are, however, eventually acted on. Thus, a new device may become active without perturbing the active flows after having gathered enough flow control information.