Abstract: Methods and arrangements for facilitating multicast communication among at least two nodes in a distributed network configured for point to point communications. Each router node is provided with a first switching arrangement adapted to route a message between a publisher node and a subscriber node in accordance with a first protocol, and a second switching arrangement adapted to route a message between the publisher node and the subscriber node in accordance with a second protocol.

Abstract: Methods and arrangements for repositioning at least one node in a distributed network. Upon detection of a failed node in the network, subscription information relating to each direct child node of the failed node is retained at each direct child node.

Abstract: A Dynamic Multicast Routing (DMR) facility is provided for a distributed computing environment having a plurality of networks of computing nodes. The DMR facility automatically creates virtual interfaces between selected computing nodes of the networks to ensure multicast message reachability to all functional computing nodes within the distributed computing environment. The DMR facility employs a group of group leader nodes (GL_group) among which virtual interfaces for multicast messaging are established. Upon failure of one of the group leader nodes, another computing node of the respective network having the failing group leader node is assigned group leader status for re-establishing virtual interfaces. Virtual interfaces are established between the group leader nodes such that redundancy in message routing is avoided.

Abstract: Dynamic reconfiguration of a quorum group of processors and recovery procedure therefore are provided for a shared nothing distributed computing system. Dynamic reconfiguration proceeds notwithstanding unavailability of at least one processor of the quorum group of processors assuming that a quorum of the remaining processors exists. Recovery processing is implementing by the group of processors so that the at least one processor which was unavailable during the dynamic reconfiguration of the group is able to obtain current state information once becoming active. Each processor of the group of processors includes an incarnation number and a list of member processors which participated in a commit process resulting in its incarnation number. The recovery processing includes exchanging the processors' incarnation numbers and lists of processors for propagation of the current state of the quorum group of processors to the at least one processor now becoming available.

Abstract: Dynamic reconfiguration of a quorum group of processors and recovery procedure therefore are provided for a shared nothing distributed computing system. Dynamic reconfiguration proceeds notwithstanding unavailability of at least one processor of the quorum group of processors assuming that a quorum of the remaining processors exists. Recovery processing is implementing by the group of processors so that the at least one processor which was unavailable during the dynamic reconfiguration of the group is able to obtain current state information once becoming active. Each processor of the group of processors includes an incarnation number and a list of member processors which resulted from a commit process resulting in its incarnation number. The recovery processing includes exchanging the processors' incarnation numbers and lists of processors for propagation of the current state of the quorum group of processors to the at least one processor now becoming available.

Abstract: A Dynamic Multicast Routing (DMR) facility is provided for a distributed computing environment having a plurality of networks of computing nodes. The DMR facility automatically creates virtual interfaces between selected computing nodes of the networks to ensure multicast message reachability to all functional computing nodes within the distributed computing environment. The DMR facility employs a group of group leader nodes (GL_group) among which virtual interfaces for multicast messaging are established. Upon failure of one of the group leader nodes, another computing node of the respective network having the failing group leader node is assigned group leader status for re-establishing virtual interfaces. Virtual interfaces are established between the group leader nodes such that redundancy in message routing is avoided.

Abstract: A fractal process scheduler for testing applications in a distributed processing system having a plurality of nodes. The scheduler includes an originating file containing a sequence of statements, each statement representing a fractal cell, an input file comprising statements from said originating file which generate vertices, a fractal parser for compiling the statements from the input file, one or more intermediate files produced by the fractal parser comprising intermediate results. The intermediate files are executable for scheduling a process of the application being tested to nodes of the distributed processing system. The schedular further includes a master file produced by said fractal parser, said master file which is executable for scheduling a process of the application being tested to nodes of the distributed processing system. The fractal parser maps the input file into the intermediate file and the master file in accordance with complex fractal expansions.

Abstract: A Dynamic Multicast Routing (DMR) facility is provided for a distributed computing environment having a plurality of networks of computing nodes. The DMR facility automatically creates virtual interfaces between selected computing nodes of the networks to ensure multicast message reachability to all functional computing nodes within the distributed computing environment. The DMR facility employs a group of group leader nodes (GL_group) among which virtual interfaces for multicast messaging are established. Upon failure of one of the group leader nodes, another computing node of the respective network having the failing group leader node is assigned group leader status for re-establishing virtual interfaces. Virtual interfaces are established between the group leader nodes such that redundancy in message routing is avoided.