Abstract: In order to solve the problem of the detection of the arrival of duplicate data packets in an interconnected, multinode data processing system, each data packet is provided with a field of r bits that are randomly generated for each data packet. However, one of the packets is provided with a field that is computed from the other randomly generated field entries in a checksum computation which yields a selected nonzero checksum value. A running checksum at the receiver is used to determine whether or not, after the receipt of the specified number, k, of data packets, a duplicate packet has been received.

Abstract: A method, information processing system, and computer readable medium manage a plurality of network interfaces. A data packet is accepted at a pseudo network interface. The pseudo network interface manages a plurality of underlying physical network interfaces. The pseudo network interface selects selected physical network interface from the plurality of physical network interfaces for outputting the data packet. The data packet is modified to include a hardware address associated with the selected physical network interface in response to the selecting. The data packet that has been modified is forwarded to the physical network interface that has been selected.

Abstract: In remote direct memory access transfers in a multinode data processing system in which the nodes communicate with one another through communication adapters coupled to a switch or network, failures in the nodes or in the communication adapters can produce the phenomenon known as trickle traffic, which is data that has been received from the switch or from the network that is stale but which may have all the signatures of a valid packet data. The present invention addresses the trickle traffic problem in two situations: node failure and adapter failure. In the node failure situation randomly generated keys are used to reestablish connections to the adapter while providing a mechanism for the recognition of stale packets. In the adapter failure situation, a round robin context allocation approach is used with adapter state contexts being provided with state information which helps to identify stale packets.

Abstract: In a multinode data processing system in which nodes exchange information over a network or through a switch, the mechanism which enables out-of-order data transfer via Remote Direct Memory Access (RDMA) also provides a corresponding ability to carry out broadcast operations, multicast operations, third party operations and conditional RDMA operations. In a broadcast operation a source node transfers data packets in RDMA fashion to a plurality of destination nodes. Multicast operation works similarly except that distribution is selective. In third party operations a single central node in a cluster or network manages the transfer of data in RDMA fashion between other nodes or creates a mechanism for allowing a directed distribution of data between nodes. In conditional operation mode the transfer of data is conditioned upon one or more events occurring in either the source node or in the destination node.

Abstract: In a multinode data processing system in which nodes exchange information over a network or through a switch, a structure and mechanism is provided within the realm of Remote Direct Memory Access (RDMA) operations in which DMA operations are present on one side of the transfer but not the other. On the side in which the transfer is not carried out in DMA fashion, transfer processing is carried out under program control; this is in contrast to the transfer on the DMA side which is characteristically carried out in hardware. Usage of these combination processes is useful in programming situations where RDMA is carried out to or from contiguous locations in memory on one side and where memory locations on the other side is noncontiguous. This split mode of transfer is provided both for read and for write operations.

Abstract: A method, computing node, and computer program storage product maintain network routing information. A first node receives a route status request from a second node. A status is stored at the first node indicating that a route from the second node to the first node is valid only in response to receiving the route status request. The first node transmits a route status reply to the second node.

Abstract: A method, information processing system, and computer readable medium, mitigate processor assignments. A first processor in a plurality of processors is assigned to a first communication port in a plurality of communication ports. An interrupt associated with the first communication port is generated. An assignment of a processor other than the first processor to handle the interrupt is inhibited.

Abstract: In order to solve the problem of the detection of the arrival of duplicate data packets in an interconnected, multinode data processing system, each data packet is provided with a field of r bits that are randomly generated for each data packet. However, one of the packets is provided with a field that is computed from the other randomly generated field entries in a checksum computation which yields a selected nonzero checksum value. A running checksum at the receiver is used to determine whether or not, after the receipt of the specified number, k, of data packets, a duplicate packet has been received.

Abstract: In order to solve the problem of the detection of the arrival of duplicate data packets in an interconnected, multinode data processing system, each data packet is provided with a field of r bits that are randomly generated for each data packet. However, one of the packets is provided with a field that is computed from the other randomly generated field entries in a checksum computation which yields a selected nonzero checksum value. A running checksum at the receiver is used to determine whether or not, after the receipt of the specified number, k, of data packets, a duplicate packet has been received.

Abstract: A method, computing node, and computer program storage product maintain network routing information. A first node receives a route status request from a second node. A status is stored at the first node indicating that a route from the second node to the first node is valid only in response to receiving the route status request. The first node transmits a route status reply to the second node.

Abstract: A method, information processing system, and computer readable medium manage a plurality of network interfaces. A data packet is accepted at a pseudo network interface. The pseudo network interface manages a plurality of underlying physical network interfaces. The pseudo network interface selects selected physical network interface from the plurality of physical network interfaces for outputting the data packet. The data packet is modified to include a hardware address associated with the selected physical network interface in response to the selecting. The data packet that has been modified is forwarded to the physical network interface that has been selected.

Abstract: A method, information processing system, and computer readable medium, mitigate processor assignments. A first processor in a plurality of processors is assigned to a first communication port in a plurality of communication ports. An interrupt associated with the first communication port is generated. An assignment of a processor other than the first processor to handle the interrupt is inhibited.

Abstract: In a multinode data processing system in which nodes exchange information over a network or through a switch, the mechanism which enables out-of-order data transfer via Remote Direct Memory Access (RDMA) also provides a corresponding ability to carry out broadcast operations, multicast operations, third party operations and conditional RDMA operations. In a broadcast operation a source node transfers data packets in RDMA fashion to a plurality of destination nodes. Multicast operation works similarly except that distribution is selective. In third party operations a single central node in a cluster or network manages the transfer of data in RDMA fashion between other nodes or creates a mechanism for allowing a directed distribution of data between nodes. In conditional operation mode the transfer of data is conditioned upon one or more events occurring in either the source node or in the destination node.

Abstract: In a multinode data processing system in which the nodes communicate with one another through communication adapters coupled to a switch or network, a method is provided for using the Internet Protocol (IP) for transmitting large broadcast data packets without incurring the overhead normally associated with packet fragmentation. By adding an Internet Protocol (IP) header as the first header in every packet fragment in the fragmentation process, fragmented packets are able to be assembled in the IP layer without intervention at the adapter interface layer.

Abstract: In a multinode data processing system in which nodes exchange information over a network or through a switch, the mechanism which enables out-of-order data transfer via Remote Direct Memory Access (RDMA) also provides a corresponding ability to carry out broadcast operations, multicast operations, third party operations and conditional RDMA operations. In a broadcast operation a source node transfers data packets in RDMA fashion to a plurality of destination nodes. Multicast operation works similarly except that distribution is selective. In third party operations a single central node in a cluster or network manages the transfer of data in RDMA fashion between other nodes or creates a mechanism for allowing a directed distribution of data between nodes. In conditional operation mode the transfer of data is conditioned upon one or more events occurring in either the source node or in the destination node.

Abstract: A remote direct memory access (RDMA) system is provided in which data is transferred over a network by DMA between from a memory of a first node of a multi-processor system having a plurality of nodes connected by a network and a memory of a second node of the multi-processor system. The system includes a first network adapter at the first node, operable to transmit data stored in the memory of the first node to a second node in a plurality of portions in fulfillment of a DMA request. The first network adapter is operable to transmit each portion together with identifying information and information identifying a location for storing the transmitted portion in the memory of the second node, such that each portion is capable of being received independently by the second node according to the identifying information. Each portion is further capable of being stored in the memory of the second node at the location identified by the location identifying information.

Abstract: In a multinode data processing system in which nodes exchange information over a network or through a switch, the mechanism which enables out-of-order data transfer via Remote Direct Memory Access (RDMA) also provides a corresponding ability to carry out broadcast operations, multicast operations, third party operations and conditional RDMA operations. In a broadcast operation a source node transfers data packets in RDMA fashion to a plurality of destination nodes. Multicast operation works similarly except that distribution is selective. In third party operations a single central node in a cluster or network manages the transfer of data in RDMA fashion between other nodes or creates a mechanism for allowing a directed distribution of data between nodes. In conditional operation mode the transfer of data is conditioned upon one or more events occurring in either the source node or in the destination node.

Abstract: A method for clipping a line segment boundary-defined area against a limiting plane is disclosed for use in a computer graphics display system wherein graphics figures are represented by random sets of polylines definitive of line segment boundary-defined areas. Pursuant to the clipping method, once two intersection points are generated against one plane, the points are connected to form an edge of the new clipped boundary-defined area. The order of intersection point connection is irrelevant to the invention and the method can accomodate discontinuously presented data as readily as continuously presented data. Implementing the method essentially requires only one register to store the first intersection point and a flag register to indicate the status of the present clip point, i.e., whether the clipped point is the first or second of two points to be paired.