International Business Machines Corporation

Nicholas P Rash

Robert Francis Bartfai

Kevin J Reilly

Jay Robert Herring

Carl Alfred Bender

John Divirgilio

John W Doxtader

Karen F Rash, Legal Representative

Craig Brian Stunkel

Aruna V Ramanan

Derrick LeRoy Garmire

Francis Alfred Kampf

LeRoy R Lundin

Peter J LeVangia

Laura J Merritt

Mark G Atkins

Alison B White

Dawn S Moyer

In a communications network having a plurality of nodes adapted to communicate with each other, and more than one path available between most source-destination node-pairs, a network interface is associated with each node. Each network interface has a plurality of route tables for defining a plurality of routes for transferring each packet from a source node to a destination node. Each network interface further includes a path status table of path status indicators, e.g., bits, for indicating whether each route in the route tables is usable or is unusable as being associated with a fault. The network manager monitors the network to identify faults and provides the path status indicators to the respective network interfaces. Failed routes in the network are avoided based on the path status indicators. When a failed route is restored, such that the route is usable again, the path status table indicates that the usable state is restored. A balance of route usage in the network is maintained, without modifying routes or establishing different routes, enabling reliable and high-performance message transfer.

Reliable message transfer over an unreliable network

Endpoint identifiers are dynamically assigned to network interfaces, in response to a change in physical connection. When a physical connection associated with a network interface is changed, such as a cable coupling the network interface to an endpoint is moved from one location to another location, a new endpoint identifier is assigned to the network interface. The new endpoint identifier is based on the location of the new endpoint.

Dynamically assigning endpoint identifiers to network interfaces of communications networks

A series of state transitions is indicative of performance of hardware service actions. A transition from, for instance, a disconnected state to a connected state for a hardware component is indicative of performance of a service action for the hardware component. Detection of this transition is automatic.

Facilitating detection of hardware service actions

A network exploration is performed to initialize one or more network elements of the network. If during the network exploration a failure is encountered, a systematic and deterministic approach is used to accurately and particularly identify the faulty network component that caused the failure.

Identifying faulty network components during a network exploration

Adapters, which provide message communications capabilities in a multinode data processing network, are provided with a mechanism for indicating critical errors from which recovery may ultimately be possible. Error handling capabilities are incorporated which operate both globally and locally to insure, to the greatest extent possible, that applications running on the network are not prematurely terminated and that the node with the error affected adapter is not prematurely removed from its connectivity with the other nodes within it network group.

Critical adapter local error handling

A method, and a system for implementing the method, for implementing the method, for determining if a wire has been miswired in a network comprising service nodes and switch elements. The method includes the steps of: (1) transmitting a transmission stream in an outbound route, (where this transmission stream includes one or more service node fields for one or more service nodes, one or more switch element fields for one or more switch elements connected to the one or more service nodes, and a port field for each the switch element); (2) if the transmission stream is received on a port at a the switch element different than a the port field for the switch element indicated by the transmission stream, then setting an error indicator in the transmission stream; (3) transmitting the transmission stream back to the one or more service nodes in a return route, where the one or more service nodes determine from the error indicator a miswired condition between the receiving switch element and a previous switch element or service node along the outbound route. The one or more service nodes can record, store and tabulate the miswired condition and one or more additional miswired conditions. The transmission stream can store the one or more switch element fields for the one or more switch elements and the port fields for each the switch element separately for a path comprising the outbound route and a path comprising the return route.

Mechanism and procedure for detecting switch mis-cabling

An apparatus for synchronizing operator commands with a failover process in a distributed system having a control workstation and a plurality of nodes. One of the nodes of the distributed system is designated a primary node and one of the nodes is designated a backup node. The backup node includes a backup daemon for performing a failover process if the primary node fails such that the backup node becomes the primary node. Shell scripts send a command string to be synchronized with the operation of the backup daemon from the control workstation to the backup node. The backup daemon is then checked to determine if the backup daemon is sleeping, and, in the event the backup daemon is sleeping, commands derived from the command string are enqueued in a work queue for processing by the backup daemon. The backup daemon is then awakened such that the derived commands in the work queue are processed. In the event that the backup daemon is busy, commands derived from the command string are failed, thereby synchronizing the derived commands with the processing of the backup daemon.

Apparatus for synchronizing operator initiated commands with a failover

A quiesced and synchronous distributed data processing system includes a primary node, a secondary node and a switch between the primary and secondary nodes. The TOD for the primary node is set depending on the system. The invention sets the TOD for the switch based on the TOD of the primary node. The primary node then verifies the switch TOD. If verified, the TOD for the secondary node is set, based on the TOD of the primary node. Finally, the secondary node self-verifies its TOD.

Verifying a time-of-day counter

A method and program product for synchronizing operator commands with a failover process in a distributed system having a control workstation and a plurality of nodes. One of the nodes of the distributed system is designated a primary node and one of the nodes is designated a backup node. The backup node includes a backup daemon for performing a failover process if the primary node fails such that the backup node becomes the primary node. Shell scripts send a command string to be synchronized with the operation of the backup daemon from the control workstation to the backup node. The backup daemon is then checked to determine if the backup daemon is sleeping, and, in the event the backup daemon is sleeping, commands derived from the command string are enqueued in a work queue for processing by the backup daemon. The backup daemon is then awakened such that the derived commands in the work queue are processed. In the event that the backup daemon is busy, commands derived from the command string are failed, thereby synchronizing the derived commands with the processing of the backup daemon.

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Poughkeepsie, NY, United States of America

Nicholas P Rash