International Business Machines Corporation

James L Ashton

Robert Thomas Uthe

James P Gray

Guy Platel

Jeffrey G Knauth

Lawrence Edward Troan

Keith E Karlsson

Michael F Gierlach

Robert T Gibbs

Karl David McCormick, Ii

Robert Davis Porter

Divakara K R Udupa

William Notley Maddox

Stuart W Pretzman

A network management system monitors and controls a frame relay network using management information transmitted directly or across the frame relay network itself in network management services vectors intended for the sole purpose of transmitting network management information to the network management system. Newly defined network management major vector formats are used to transmit detailed information concerning both the status of the various virtual circuit segments in the network and the configuration of the switched connections between those segments to form virtual circuits through the network for communication between users of the network. More particularly, status bits are defined to indicate that data links nodes are not supported by adjacent nodes of the network, and status bits to indicate likely physical failures in the hardware used to realize the data links, or logical faults involved in inconsistent indications from adjacent nodes. This status and configuration data is used, in turn, at the network management system to control the network, to diagnose problems, and to effect failure recovery procedures.

Management of packet transmission networks

Method and apparatus in a communications controller to transfer data between a host computer and the controller. The communications controller includes a channel adapter (CA) and a central control unit (CCU) for controlling the operation of the CA. In response to a request from the CCU, the channel adapter transfers data between the host computer and the channel adapter to or from a linked list of buffers until all messages contained in the linked list have been transferred. Only after all messages in the present transmission have been transferred, the CA interrupts the CCU to signal completion. In a preferred embodiment, the channel adapter includes a microprocessor and a read-only-memory containing programmed instructions for controlling the microprocessor. Together, the microprocessor under control of the read-only-memory instructions form an apparatus for carrying out the method.

Method and apparatus for buffer chaining in a communications controller

A method of operating a communication system which includes a number of host systems each communicating via sessions with other devices over different connections and in which the sessions assigned to a failed connection are suspended for a first and second time period and non-destructively moved to an alternate connection when a unique command is issued by one of the host systems and received by a control unit involved in the failed connection.

Non-disruptive session recovery

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Cary, NC, United States of America

James L Ashton