Abstract: A method and apparatus for switching messages from a primary message channel to a secondary message channel in a message queuing system in which messages are placed in a first transmission queue of a local system for transmission to a remote system via a primary message channel. A local queue manager continuously checks to see whether a high water mark has been reached in the first transmission queue, indicating an apparent failure in the primary message channel. On determining such an apparent failure in the primary message channel, the queue manager determines whether the secondary message channel is associated with the first transmission queue. If so, the queue manager activates the secondary message channel to serve said first transmission queue. If, on the other hand, the secondary message channel is associated with another transmission queue, the queue manager transfers messages already in the first queue to the other queue and redirects any new messages intended for the first queue to the other queue.

Abstract: A common shared queue is provided, which includes a plurality of local queues. Each local queue is resident on a storage medium coupled to a processor. The local queues are monitored, and when it is determined that a particular local queue is being inadequately serviced, then one or more messages are moved from that local queue to one or more other local queues of the common shared queue.

Abstract: Management of datastream construction prior to transmission of the datastream across a channel of a communications system by providing for data blocking while reducing movement or copying of the data improves the performance in a communications system. Multiple header segments received from a higher layer in the communications stack are copied into the datastream header area of a datastream such that the header segments are sequentially stored in the datastream header area. A datastream buffer list having entries referencing the datastream header area is generated. Buffer list entries referencing data segments received from higher layers in the communications stack are also stored in the datastream buffer list. The data segments are not physically moved or copied into the datastream during processing by the communications stack. Rather, a "virtual" datastream is generated by the communications stack for transmission without physically moving or copying the data segment.

Abstract: Management of the processing of relatively large data objects in a communications stack having multiple layers improves the performance in a communications system in preparing relatively large data objects for transmission across a communications network. This reduces or eliminates data movement and copying during segmentation of the relatively large data objects into relatively small data objects, and appendage of headers to the relatively small data object segments during processing in the communications stack. A shared storage manager creates and controls multiple tokens representing multiple images of portions of the relatively large data objects to enable separate scheduling of the multiple images from the same storage unit or buffer to be passed from one layer in a communications stack to the next lower layer in the communications stack. The large data object is segmented into a plurality of relatively small data object segments at one or more of the layers in the communications stack.